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. Author manuscript; available in PMC: 2025 Aug 5.
Published in final edited form as: Am J Vet Res. 2025 Jul 2;86(9):1–12. doi: 10.2460/ajvr.25.01.0016

Self-reported dog vaccination practices in pet owners enrolled in the Dog Aging Project in the United States found most dogs were vaccinated according to veterinarians’ recommendations

John E Ekakoro 1,2,3, Audrey Ruple 4,*; Dog Aging Project Consortium, David Renter 1,2, Natalia Cernicchiaro 1,2
PMCID: PMC12324815  NIHMSID: NIHMS2101052  PMID: 40623437

Abstract

Objective

To assess the associations between pet owners’ demographic characteristics and vaccination status of dogs at the time of enrollment into the Dog Aging Project and describe the vaccination practices against core and noncore pathogens.

Methods

This cross-sectional study assessed responses of US dog owners to the Dog Aging Project Health and Life Experience Survey, administered at enrollment from 2019 through 2023, and the 2023 annual follow-up survey. A multivariable multinomial logistic regression model was built to investigate factors associated with dog vaccination status.

Results

Almost all owners (44,935 of 47,444 [94.7%]) reported that their dog was vaccinated against various diseases as recommended by their veterinarian. Dogs owned by respondents with a bachelor’s degree compared to those of respondents with less than a bachelor’s degree education level were significantly more likely (relative risk ratio, 3.58; 95% CI, 2.26 to 5.67) to be vaccinated per their veterinarian’s recommendations. Compared to dogs of respondents with an annual income less than $20,000, dogs of respondents with an annual income ranging from $40,000 to $59,999 were significantly more likely (relative risk ratio, 5.24; 95% CI, 2.32 to 11.85) to be vaccinated as recommended by their veterinarian.

Conclusions

This study found a high level of adherence to veterinarians’ recommendations for vaccinations. Dog vaccine uptake was higher among respondents with a bachelor’s degree or higher education level and among those with higher annual incomes.

Clinical Relevance

Vaccine literacy programs targeting and measures that aim to increase dog vaccine uptake among low-income pet owners may be necessary.

Keywords: vaccines, companion dog vaccination, veterinary recommendation, core vaccines, client communication

Dog vaccination is a key aspect of both infectious disease prevention and maintenance of health, longevity, and quality of life.1 Dog vaccination is also important for public health through the prevention and control of zoonotic diseases, such as rabies.2,3 Dog vaccines are classified into core vaccines, those that all dogs should receive regardless of circumstances, and noncore vaccines, those that are required by only those dogs whose circumstances, such as lifestyle, geographic region, or local environment, increase their risk of exposure to specific infections.4 Before canine vaccination guidelines were updated in 20245 to include Leptospira vaccines among core vaccines in the US, the recommended core vaccines for infectious diseases of dogs included rabies, canine distemper virus, canine adenovirus, and parvovirus, whereas noncore vaccines included Leptospira, Borrelia burgdorferi, Bordetella bronchiseptica, canine parainfluenza virus, and canine influenza virus.1 Canine Lyme disease may be considered core by veterinary practices in locations where these diseases are endemic.1

Variability in dog vaccination coverage has been reported in developed countries, including Germany,6 the United Kingdom (UK),7 and the United States (US).8 In the US, substantial variability was found in noncore vaccination of dogs and cats, and factors other than disease risk, such as the cost associated with vaccination, were suggested to be responsible for the variability.8 In Germany, dog vaccination status did not meet the guidelines for core vaccines, although veterinary recommendations strongly influenced vaccination practices.6 A study in the UK found that dogs were more frequently vaccinated against Leptospira when compared to core vaccines, and owner vaccination practices were influenced by factors such as dog breed, dog neuter status, dog health insurance status, and the socioeconomic status of the owner.7

Vaccine hesitancy may be another factor influencing dog vaccination practices. One study9 found that 52% of dog owners in the US were, to some degree, hesitant to vaccinate their dogs, and this hesitancy was associated with a lack of compliance with recommended rabies vaccination and opposition to evidence-based vaccination policies. In another US study,10 veterinarians reported that pet owners’ hesitancy or resistance to vaccines was due to the perceptions that their animals are at a low risk of exposure to infectious diseases or that vaccines were unnecessary, associated with adverse events, and costly. This study10 also reported that an increased number of dog owners were hesitant or resistant to vaccinating their dogs against rabies and other core vaccine–preventable diseases since the time COVID-19 vaccines became available. Vaccine-associated adverse events are perceived by pet owners and veterinarians to be associated with certain precipitating factors, such as general use of vaccines or certain vaccines.11

Understanding the factors influencing vaccination rates is important in order to optimize efforts made to increase vaccine uptake among dog owners. Currently, there is a scarcity of studies conducted in the US that examine dog vaccination practices and adherence of owners to recommended vaccination protocols. Additionally, there is a lack of comprehensive knowledge of the factors influencing the vaccination practices of US dog owners. This study, therefore, aimed to fill these knowledge gaps using data from the Dog Aging Project (DAP).12 The DAP is a long-term longitudinal study that combines both retrospective cross-sectional and prospective longitudinal data collected from owners of tens of thousands of companion dogs of all breeds, ages, sizes and sexes living in all geographic regions of the US.12 The objectives of the present study were to assess the associations between owner demographic characteristics and vaccination status of dogs at enrollment into the DAP in the US and describe the vaccination practices of dog owners against core and noncore pathogens.

Methods

Data sources

This study used electronic survey data from the DAP Health and Life Experience Survey (HLES) that was completed by dog owners at the time of enrollment from 2019 through 2023 and the annual follow-up survey (AFUS), which was completed annually thereafter. The DAP recruits dog owners through mainstream media, social media, and word of mouth,12 and any person who nominates a dog receives an invitation to complete the HLES. The HLES survey collects data on the state and region of primary residence (where the owner and the dog primarily reside/live for the majority of time); dog population characteristics (age, sex, breed, spay/neuter status, dog health insurance status, etc); owner’s age, education level, and annual pretax income level; medications, preventatives, and supplements used; and a comprehensive health history, among other information. The region of primary residence was classified according to US census designations as New England (division 1), Middle Atlantic (division 2), East North Central (division 3), West North Central (division 4), South Atlantic (division 5), East South Central (division 6), West South Central (division 7), Mountain (division 8), and Pacific (division 9).13 The HLES data used were cross-sectional in nature, similar to previous cross-sectional studies14,15 that utilized the DAP data. The datasets used in the present study were downloaded from the DAP 2023 curated data release housed on the Terra platform at the Broad Institute of the Massachusetts Institute of Technology and Harvard.16 Institutional review board approval was not required because secondary data were used. The HLES contained a question on whether the respondent’s dog had been vaccinated, and the responses were nominal and polytomous, captured as “yes, my dog is vaccinated against various diseases as recommended by my veterinarian,” “yes, my dog is vaccinated only against rabies virus,” “yes, my dog was vaccinated as a puppy but not as an adult,” “no, my dog is not vaccinated,” and “I don’t know.”

The AFUS is administered to all members of the DAP on the yearly anniversary of their completion of the HLES, and the data are provided in a different dataset separate from the HLES data. This survey included questions on how often the dog receives a rabies vaccine, canine distemper combination vaccine (which includes canine parvovirus and adenovirus 2), leptospirosis vaccine, kennel cough vaccine (which includes parainfluenza virus and/or B bronchiseptica), canine influenza vaccine (either or both strains), and B burgdorferi vaccine (Lyme disease vaccine). The responses to the AFUS vaccination questions were captured as “receives every year,” “receives more than once per year (eg, every 6 months),” “receives less frequently than annually (eg, every 3 years),” “receives occasionally but not on a formal schedule,” “received previously but not giving any longer,” “received as a puppy but not since,” “has received, but I am unsure about the schedule,” “has previously received but no longer being vaccinated,” “has never received,” and “I am unsure if they have received.”

Data management and analysis

Responses to the question on the respondent’s education level were categorized as previously described by a DAP study,17 with “less than bachelor’s degree” including respondents with no schooling completed; nursery school to 8th grade; some high school but no diploma; high school graduate; high school equivalent degree (such as GED); some college credit (no degree); trade, technical, or vocational training; and associate’s degree. Other educational levels were captured as bachelor’s degree, master’s degree, professional degree (such as DVM, MD, DDS, or JD), and doctorate degree (such as PhD, DrPH, or DPhil). The responses to the HLES question on whether the respondent’s dog had been vaccinated were modified into “vaccinated against various diseases as recommended by my veterinarian,” “vaccinated only against rabies virus,” “vaccinated as a puppy but not as an adult,” “not vaccinated,” and “didn’t know the dog’s vaccination status.” The responses to the AFUS vaccination questions were recategorized into 6 categories, which included “receives annually (every year),” “receives more than once per year (eg, every 6 months),” “receives less frequently than annually (eg, every 3 years),” “received previously, not since,” “has never received”, and “unsure.” The new category “received previously, not since” included “receives occasionally but not on a formal schedule,” “received previously but not giving any longer,” “received as a puppy but not since,” “has received, but I am unsure about the schedule,” and “has previously received but no longer being vaccinated.” All data management and statistical analyses were performed in Stata, version 18.0 (StataCorp).18 The questionnaires and the datasets analyzed are publicly available through Terra in the DAP 2023 Curated Workspace.16 The statistical code used can be obtained from the corresponding author upon reasonable request.

Statistical analysis

Frequencies and proportions were computed to summarize the data, and the distributions of the outcome variables based on the characteristics of the respondents are presented. The vaccination practices reported in the AFUS are presented only for the year 2023, the latest year of follow-up, based on the framing of the AFUS vaccination questions that yielded similar responses per respondent across follow-up years. A multinomial logistic regression model was used to estimate the associations between owner’s demographic characteristics (owner’s age, education level, annual pretax income, primary residence location, breed of dog owned, dog insurance status, and sex of dog owned) and the reported vaccination status of the dog in the HLES (at enrollment). Data for owners who did not know the vaccination status of their dogs were excluded from the multinomial model building due to the small number of participants in this category (n = 20). In the multinomial logistic regression, the response category “not vaccinated” was used as the baseline level, and relative risk ratio (RRR) estimates for “vaccinated as recommended by a veterinarian,” “vaccinated only against rabies virus,” “vaccinated as a puppy but not as an adult,” and “did not know the dog’s vaccination status” were computed and compared to the baseline.

A 2-step model-building process was used, where a univariable multinomial logistic regression model was first fitted to assess the association between each potential explanatory factor and the outcome. Potential explanatory variables with P values ≤ .2 were considered for inclusion in the multivariable multinomial logistic regression model. Potential explanatory variables that were ordinal and significant at P ≤ .2 were assessed for collinearity using the Spearman rank correlation coefficient (ρ > 0.8 was considered to be highly correlated),19 and no collinearity was found. In the second step, a manual backwards-selection approach was used to fit the multivariable model, and statistical significance was set at P < .05. The overall effect of an explanatory variable in the multivariable model was determined using the Stata test command. Potential confounding was assessed by comparing the change in the magnitude of the measure of association (RRR) with and without the suspected confounders. If a 20% or greater change in the RRR of another variable occurred upon removal of the suspected confounder, the suspected confounder would be retained in the final model regardless of its statistical significance.20 Based on biological plausibility, 2-way interactions between sex of dog owned and pedigree status of the dog were tested. Relative risk ratios and their 95% CIs were computed for all variables in the final model. Model goodness of fit was assessed using Akaike information criterion and Bayesian information criterion obtained using the fitstat command in Stata.

Results

Characteristics of the study population

Of the 47,444 respondents who completed the HLES at enrollment, 22 (0.1%) completed the HLES in 2019, 27,415 (57.8%) completed it in 2020, 5,653 (11.9%) completed it in 2021, 10,379 (21.9%) completed it in 2022, and 3,975 (8.3%) completed it in 2023. There were 40,831 responses to the AFUS, and 13,917 (34.1%) were completed in 2021, 13,008 (31.9%) were completed in 2022, and 13,906 (34.1%) were completed in 2023. Of the 47,444 respondents, 23,890 (50.4%) enrolled a male dog and 23,554 (49.6%) enrolled a female dog. Of the 23,890 male dogs, 20,520 (86%) were neutered, and 21,368 of 23,554 females (91%) were spayed. Regarding the primary role and/or activities the respondent’s dog was involved in, almost all of the respondents (45,036 of 46,227 [97.4%]) mentioned that their dog was primarily kept for companionship, 354 of 7,210 (4.9%) for obedience purposes, 96 of 1,724 (5.6%) for show purposes, 71 of 1,268 (5.6%) for breeding, 140 of 3,132 (4.5%) for agility, 65 of 1,075 (6.1%) for hunting purposes, 151 of 1,387 (10.9%) for work, 18 of 438 (4.1%) for field trials, 76 of 257 (29.6%) for search and rescue purposes, 462 of 1,142 (40.5%) for service, and 335 of 3,726 (9%) for assistance or therapy.

Health and Life Experience Survey of dog vaccination status

Most owners (44,935 of 47,444 [94.7%]) reported that their dog was vaccinated against various diseases as recommended by their veterinarian at the time of enrollment. Of those who did not follow their veterinarian’s recommendations, 1,283 of 47,444 (2.7%) reported that they vaccinated only against rabies virus, 1,096 of 47,444 (2.3%) reported that they vaccinated their dog as a puppy but not as an adult, 110 of 47,444 (0.2%) reported that they did not vaccinate their dog, and 20 of 47,444 (0.04%) did not know their dog’s vaccination status (Table 1).

Table 1—

Vaccination practices of dog owners reported in the Dog Aging Project’s Health and Life Experience Survey, US, categorized by vaccine status.

Characteristic Vaccinated [n (%)] Rabies only [n (%)] Vaccinated as a puppy [n (%)] Unvaccinated [n (%)] Unknown [n (%)]
Total 44,935 1,283 1,096 110 20
Age of owner (y)
 18–24 973 (2.2) 10 (0.8) 12 (1.1) 2 (1.8) 2 (10.0)
 25–34 6,561 (14.6) 111 (8.7) 105 (9.6) 7 (6.4) 0 (0.0)
 35–44 7,206 (16.0) 152 (11.9) 176 (16.1) 16 (14.6) 5 (25.0)
 45–54 7,989 (17.8) 238 (18.6) 201 (18.3) 17 (15.5) 1 (5.0)
 55–64 10,792 (24.0) 364 (28.4) 314 (28.7) 35 (31.8) 3 (15.0)
 > 65 11,414 (25.4) 408 (31.8) 288 (26.3) 33 (30.1) 9 (45.0)
Education level
 Less than bachelor’s degree 9,004 (20.0) 397 (30.9) 406 (37.0) 56 (50.9) 9 (45.0)
 Bachelor’s degree 15,534 (34.6) 468 (36.5) 381 (34.8) 27 (24.6) 7 (35.0)
 Master’s degree 12,640 (28.1) 297 (23.2) 215 (19.6) 21 (19.1) 4 (20.0)
 Professional degree or Doctorate 7,757 (17.3) 121 (9.4) 94 (8.6) 6 (5.4) 0 (0)
Owner annual pretax income
 < $20,000 791 (1.8) 54 (4.2) 38 (3.5) 12 (10.9) 3 (15.0)
 $20,000–$39,999 2,550 (5.7) 128 (10) 97 (8.9) 20 (18.2) 3 (15.0)
 $40,000–$59,999 4,134 (9.2) 136 (10.6) 132 (12) 12 (10.9) 3 (15.0)
 $60,000–$79,999 4,853 (10.8) 150 (11.7) 143 (13.1) 9 (8.2) 0 (0)
 $80,000–$99,999 4,713 (10.5) 150 (11.7) 119 (10.9) 14 (12.7) 4 (20)
 $100,000–$119,999 4,932 (11) 125 (9.7) 103 (9.4) 8 (7.3) 2 (10)
 $120,000–$139,999 3,565 (7.9) 92 (7.2) 79 (7.2) 3 (2.7) 0 (0)
 $140,000–$159,999 2,945 (6.6) 72 (5.6) 68 (6.2) 5 (4.6) 0 (0)
 $160,000–$179,999 2,065 (4.6) 35 (2.7) 29 (2.7) 2 (1.8) 0 (0)
 $180,000 or more 8,964 (19.9) 153 (11.9) 144 (13.1) 13 (11.8) 1 (5)
 Preferred not to answer 5,423 (12.1) 188 (14.7) 144 (13.1) 12 (12.9) 4 (20)
Sex and neuter status of dog
 Male, intact 3,032 (6.8) 115 (9) 204 (18.6) 18 (16.4) 1 (5)
 Male, neutered 19,640 (43.7) 515 (40.1) 333 (30.4) 23 (20.9) 9 (45)
 Female, intact 1,923 (4.3) 65 (5.1) 170 (15.5) 27 (24.6) 1 (5)
 Female, spayed 20,340 (45.3) 588 (45.8) 389 (35.5) 42 (38.2) 9 (45)
Pedigree status of dog owned
 Single breed 22,351 (49.7) 691 (53.9) 754 (68.8) 58 (52.7) 3 (15)
 Multiple (mixed) breed 22,584 (50.3) 592 (46.1) 342 (31.2) 52 (47.3) 17 (85)
Dog insurance status
 Not insured 35,270 (78.5) 1,083 (84.4) 844 (77) 100 (90.9) 20 (100)
 Insured 9,665 (21.5) 200 (15.6) 252 (23) 10 (9.1) 0 (0)
Primary residence location
 New England 2,747 (6.1) 84 (6.6) 55 (5) 3 (2.7) 1 (5)
 Middle Atlantic 4,525 (10.1) 131 (10.2) 130 (11.9) 10 (9.1) 3 (15)
 East North Central 6,056 (13.5) 154 (12) 128 (11.7) 13 (11.8) 0 (0)
 West North Central 2,742 (6.1) 65 (5.1) 52 (4.7) 6 (5.5) 3 (15)
 South Atlantic 8,169 (18.2) 251 (19.6) 168 (15.3) 20 (18.2) 2 (10)
 East South Central 1,482 (3.3) 51 (4) 40 (3.7) 4 (3.6) 0 (0)
 West South Central 3,732 (8.3) 99 (7.7) 85 (7.8) 13 (11.8) 0 (0)
 Mountain 4,329 (9.6) 150 (11.7) 140 (12.8) 16 (14.5) 4 (20)
 Pacific 11,153 (24.8) 298 (23.2) 298 (27.2) 25 (22.7) 7 (35)
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Vaccination practices for core vaccines

Of the 13,906 respondents to the AFUS in 2023, 3,112 (22.4%) reported that their dog received rabies vaccines annually, 26 (0.2%) received rabies vaccines more than once per year, 9,711 (69.8%) received rabies vaccines less frequently than annually, 989 (7.1%) received a rabies vaccine previously but not since, 51 (0.4%) had never received a rabies vaccine, and 17 (0.1%) were unsure if their dog had received a rabies vaccine (Table 2). For distemper combination vaccine, 6,985 of 13,906 (50.2%) received it annually, 92 of 13,906 (0.6%) received it more than once per year, 3,644 of 13,906 (26.2%) received it less frequently than annually, 2,899 of 13,906 (20.9%) received it previously but not since, 67 of 13,906 (0.5%) had never received it, and 219 of 13,906 (1.6%) were unsure if their dog had received it.

Table 2—

Distribution of responses of dog owners participating in the Dog Aging Project to the 2023 annual follow-up survey of vaccination practices against core pathogens distributed by geographic region within the US (n = 13,906).

Annually More than annually Less than annually Previously Never Unsure
Vaccine No. of participants (%)
Rabies
 New England 101 (3.3) 1 (3.9) 679 (7) 44 (4.5) 1 (2) 0 (0)
 Middle Atlantic 256 (8.2) 3 (11.5) 1,030 (10.6) 80 (8.1) 1 (2) 1 (5.9)
 East North Central 427 (13.7) 3 (11.5) 1,288 (13.3) 120 (12.1) 5 (9.8) 1 (5.9)
 West North Central 211 (6.8) 1 (3.9) 559 (5.8) 50 (5.1) 0 (0) 3 (17.7)
 South Atlantic 613 (19.7) 7 (26.9) 1,835 (18.9) 126 (12.7) 2 (3.9) 1 (5.9)
 East South Central 214 (6.9) 2 (7.7) 197 (2) 25 (2.5) 0 (0) 1 (5.9)
 West South Central 360 (11.6) 1 (3.9) 624 (6.4) 63 (6.4) 4 (7.8) 1 (5.9)
 Mountain 250 (8) 2 (7.7) 1,072 (11) 117 (11.8) 4 (7.8) 2 (11.8)
 Pacific 680 (21.9) 6 (23) 2,427 (25) 364 (36.8) 34 (66.7) 7 (41.2)
 Overall 3,112 (22.4) 26 (0.2) 9,711 (69.8) 989 (7.1) 51 (0.4) 17 (0.1)
Distemper combination
 New England 349 (5) 4 (4.4) 255 (7) 197 (6.8) 5 (7.5) 16 (7.3)
 Middle Atlantic 655 (9.4) 5 (5.4) 417 (11.4) 267 (9.2) 7 (10.4) 20 (9.1)
 East North Central 1,018 (14.6) 12 (13) 441 (12.1) 345 (11.9) 6 (9) 22 (10.1)
 West North Central 438 (6.3) 3 (3.3) 214 (5.9) 156 (5.4) 4 (6) 9 (4.1)
 South Atlantic 1,410 (20.1) 22 (23.9) 608 (16.7) 498 (17.2) 6 (9) 40 (18.3)
 East South Central 313 (4.5) 4 (4.4) 50 (1.4) 66 (2.3) 0 (0) 6 (2.7)
 West South Central 631 (9) 17 (18.5) 202 (5.5) 185 (6.4) 7 (10.4) 11 (5)
 Mountain 651 (9.3) 7 (7.6) 450 (12.4) 296 (10.2) 12 (17.9) 31 (14.2)
 Pacific 1,520 (21.8) 18 (19.6) 1,007 (27.6) 889 (30.6) 20 (29.8) 64 (29.2)
 Overall 6,985 (50.2) 92 (0.6) 3,644 (26.2) 2,899 (20.9) 67 (0.5) 219 (1.6)
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Vaccination practices for noncore vaccines

Of the 13,906 respondents to the AFUS in 2023, 7,597 (54.6%) reported that their dog received Leptospira vaccines annually, 95 (0.7%) received Leptospira vaccines more than once per year, 776 (5.6%) received Leptospira vaccines less frequently than annually, 2,317 (16.6%) received a Leptospira vaccine previously but not since, 1,301 (9.4%) had never received a Leptospira vaccine, and 1,820 (13.1%) were unsure if their dog had received a Leptospira vaccine (Table 3). For the kennel cough vaccine, 7,414 of 13,906 (53.2%) received it annually, 1,014 of 13,906 (7.3%) received it more than once per year, 575 of 13,906 (4.1%) received it less frequently than annually, 3,271 of 13,906 (23.5%) received it previously but not since, 1,061 of 13,906 (7.6%) had never received it, and 571 of 13,906 (4.1%) were unsure if their dog had received it. For the canine influenza vaccine, 4,006 of 13,906 (28.8%) received it annually, 85 of 13,906 (0.6%) received it more than once per year, 382 of 13,906 (2.7%) received it less frequently than annually, 2,113 of 13,906 (15.2%) received it previously but not since, 4,438 of 13,906 (31.9%) had never received it, and 2,882 of 13,906 (20.7%) were unsure if their dog had received it. Regarding the Lyme disease vaccine, 3,491 of 13,906 (25.1%) received it annually, 47 of 13,906 (0.3%) received it more than once per year, 268 of 13,906 (1.9%) received it less frequently than annually, 1,479 of 13,906 (10.6%) received it previously but not since, 5,577 of 13,906 (40.1%) had never received it, and 3,044 of 13,906 (21.9%) were unsure if their dog had received it.

Table 3—

Distribution of responses of dog owners participating in the Dog Aging Project to the 2023 annual follow-up survey of vaccination practices against noncore pathogens distributed by geographic region within the US (n = 13,906).

Annually More than annually Less than annually Previously Never Unsure
Vaccine No. of participants (%)
Leptospira a
 New England 486 (6.4) 9 (9.5) 50 (6.4) 144 (6.2) 70 (5.4) 67 (3.7)
 Middle Atlantic 801 (10.5) 4 (4.2) 75 (9.6) 212 (9.2) 140 (10.8) 139 (7.6)
 East North Central 1,156 (15.2) 5 (5.3) 83 (10.7) 269 (11.6) 138 (10.6) 193 (10.6)
 West North Central 458 (6) 5 (5.3) 43 (5.5) 120 (5.2) 83 (6.4) 115 (6.3)
 South Atlantic 1,409 (18.5) 17 (17.9) 125 (16.1) 422 (18.2) 232 (17.8) 379 (20.8)
 East South Central 237 (3.1) 6 (6.3) 14 (1.8) 62 (2.7) 39 (3) 81 (4.4)
 West South Central 607 (8) 23 (24.2) 50 (6.4) 155 (6.7) 74 (5.7) 144 (7.9)
 Mountain 648 (8.5) 5 (5.3) 96 (12.4) 239 (10.3) 198 (15.2) 261 (14.3)
 Pacific 1,795 (23.6) 21 (22.1) 240 (30.9) 694 (29.9) 327 (25.1) 441 (24.2)
 Overall (n = 13,906) 7,597 (54.6) 95 (0.7) 776 (5.6) 2,317 (16.6) 1,301 (9.4) 1,820 (13.1)
Kennel cough
 New England 418 (5.6) 34 (3.4) 28 (4.9) 225 (6.9) 87 (8.2) 34 (5.9)
 Middle Atlantic 675 (9.1) 78 (7.7) 53 (9.2) 341 (10.4) 163 (15.4) 61 (10.7)
 East North Central 1,075 (14.5) 99 (9.8) 63 (11) 401 (12.3) 138 (13) 68 (11.9)
 West North Central 497 (6.7) 40 (3.9) 30 (5.2) 161 (4.9) 63 (5.9) 33 (5.8)
 South Atlantic 1,379 (18.6) 241 (23.8) 84 (14.6) 599 (18.3) 196 (18.5) 85 (14.9)
 East South Central 249 (3.4) 61 (6) 10 (1.7) 83 (2.5) 13 (1.2) 23 (4)
 West South Central 556 (7.5) 167 (16.5) 39 (6.8) 196 (6) 47 (4.4) 48 (8.4)
 Mountain 716 (9.7) 108 (10.6) 76 (13.2) 353 (10.8) 122 (11.5) 72 (12.6)
 Pacific 1,849 (24.9) 186 (18.3) 192 (33.4) 912 (27.9) 232 (21.9) 147 (25.7)
 Overall (n = 13,906) 7,414 (53.2) 1,014 (7.3) 575 (4.1) 3,271 (23.5) 1,061 (7.6) 571 (4.1)
Canine influenza
 New England 200 (5) 1 (1.2) 17 (4.4) 129 (6.1) 285 (6.4) 194 (6.7)
 Middle Atlantic 368 (9.2) 2 (2.4) 45 (11.8) 202 (9.6) 504 (11.4) 250 (8.7)
 East North Central 628 (15.7) 16 (18.8) 49 (12.8) 286 (13.4) 545 (12.3) 320 (11.1)
 West North Central 201 (5) 4 (4.7) 17 (4.4) 93 (4.4) 319 (7.2) 190 (6.6)
 South Atlantic 850 (21.2) 18 (21.2) 53 (13.9) 455 (21.5) 770 (17.4) 438 (15.2)
 East South Central 178 (4.4) 9 (10.6) 8 (2.1) 59 (2.8) 107 (2.4) 78 (2.7)
 West South Central 347 (8.6) 15 (17.6) 34 (8.9) 176 (8.3) 282 (6.4) 199 (6.9)
 Mountain 295 (7.4) 5 (5.9) 39 (10.2) 186 (8.8) 555 (12.5) 367 (12.7)
 Pacific 939 (23.4) 15 (17.6) 120 (31.4) 527 (24.9) 1,071 (24.1) 846 (29.4)
 Overall (n =13,906) 4,006 (28.8) 85 (0.6) 382 (2.7) 2,113 (15.2) 4,438 (31.9) 2,882 (20.7)
Borrelia burgdorferi
 New England 459 (13.2) 2 (4.3) 24 (9) 162 (11) 128 (2.3) 51 (1.7)
 Middle Atlantic 702 (20.1) 3 (6.4) 40 (14.9) 186 (12.6) 323 (5.8) 117 (3.8)
 East North Central 624 (17.9) 11 (23.4) 44 (16.4) 197 (13.3) 623 (11.2) 345 (11.3)
 West North Central 252 (7.2) 1 (2.1) 14 (5.2) 82 (5.5) 300 (5.4) 175 (5.8)
 South Atlantic 734 (21) 11 (23.4) 43 (16) 311 (21) 926 (16.6) 559 (18.4)
 East South Central 91 (2.6) 4 (8.5) 2 (0.8) 45 (3) 166 (3) 131 (4.3)
 West South Central 156 (4.5) 6 (12.8) 22 (8.2) 88 (6) 476 (8.5) 305 (10)
 Mountain 115 (3.3) 1 (2.1) 25 (9.3) 99 (6.7) 844 (15.1) 363 (11.9)
 Pacific 358 (10.3) 8 (17) 54 (20.2) 309 (20.9) 1,791 (50.9) 998 (32.8)
 Overall (n = 13,906) 3,491 (25.1) 47 (0.3) 268 (1.9) 1,479 (10.6) 5,577 (40.1) 3,044 (21.9)
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a

Leptospira vaccine is reported here as noncore because these data reflect the vaccination practices against leptospirosis based on the canine vaccination guidelines that existed before the American Animal Hospital Association updated those guidelines in 2024 to include Leptospira vaccine as core.

Simple associations between explanatory variables and vaccination status at enrollment into the DAP

There was a statistically significant association between owner’s age (P < .001), education level (P < .001), annual pretax income (P < .001), breed of dog (P < .001), dog insurance status (P < .001), primary residence location (P < .001), and sex of dog owned (P < .024) with dog’s vaccination status (Table 4). These variables were therefore considered for inclusion in the multivariable model.

Table 4—

Associations between explanatory variables with vaccination status at the time of enrollment into the Dog Aging Project from univariable multinomial logistic regression models.

Vaccinated as recommended Rabies only Vaccinated as a puppy
Characteristic RRR (95% CI) P value RRR (95% CI) P value RRR (95% CI) P value
Age of owner (y)
 > 75 0.71 (0.14–3.51) .673 2.87 (0.51–16.15) .233 1 (0.18–5.63) 1
 65–74 0.71 (0.17–2.99) .643 2.38 (0.5–11.44) .277 1.56 (0.33–7.32) .576
 55–64 0.63 (0.15–2.64) .531 2.08 (0.44–9.87) .357 1.5 (0.32–6.95) .608
 45–54 0.97 (0.22–4.19) .963 2.8 (0.57–13.81) .206 1.97 (0.41–9.53) .399
 35–44 0.93 (0.21–4.03) .918 1.9 (0.38–9.44) .433 1.83 (0.38–8.92) .453
 25–34 1.93 (0.4–9.29) .414 3.17 (0.58–17.35) .183 2.5 (0.47–13.43) .285
 18–24 Referent
Education level
 Doctorate 11.22 (2.74–45.99) .001 3.88 (0.92–16.35) .065 2.9 (0.68–12.3) .149
 Professional 6.45 (2.34–17.8) < .001 2.33 (0.82–6.63) .114 1.79 (0.62–5.15) .278
 Master’s degree 3.74 (2.26–6.18) < .001 1.99 (1.18–3.37) .01 1.41 (0.83–2.39) .2
 Bachelor’s degree 3.58 (2.26–5.67) < .001 2.44 (1.52–3.94) < .001 1.95 (1.2–3.14) .007
 Less than bachelor’s degree Referent
Owner’s annual pretax income
 Preferred not to answer 6.86 (3.07–15.31) < .001 3.49 (1.48–8.19) .004 3.79 (1.58–9.1) .003
 $180,000 or more 10.46 (4.76–23) < .001 2.62 (1.12–6.08) .026 3.5 (1.48–8.28) .004
 $160,000–$179,999 15.66 (3.5–70.14) < .001 3.89 (0.82–18.43) .087 4.58 (0.95–22.07) .058
 $140,000–$159,999 8.94 (3.14–25.44) < .001 3.2 (1.06–9.63) .038 4.29 (1.41–13.11) .01
 $120,000–$139,999 18.03 (5.08–64.03) < .001 6.81 (1.84–25.23) .004 8.31 (2.21–31.22) .002
 $100,000–$119,999 9.35 (3.81–22.95) < .001 3.47 (1.34–8.98) .01 4.07 (1.54–10.71) .005
 $80,000–$99,999 5.11 (2.35–11.08) < .001 2.38 (1.04–5.47) .041 2.68 (1.14–6.3) .023
 $60,000–$79,999 8.18 (3.44–19.48) < .001 3.7 (1.48–9.28) .005 5.02 (1.97–12.79) .001
 $40,000–$59,999 5.23 (2.34–11.68) < .001 2.52 (1.07–5.95) .035 3.47 (1.44–8.36) .005
 $20,000–$39,999 1.93 (0.94–3.97) .073 1.42 (0.65–3.11) .378 1.53 (0.68–3.44) .301
 < $20,000 Referent
Sex of dog owned
 Female 0.58 (0.4–0.86) .006 0.62 (0.41–0.92) .018 0.62 (0.41–0.93) .02
 Male Referent
Pedigree status of dog owned
 Multiple (mixed) breed 1.13 (0.77–1.64) .532 0.96 (0.65–1.41) .819 0.51 (0.34–0.75) .001
 Single breed Referent
Dog insurance status
 Insured 2.74 (1.43–5.25) .002 1.85 (0.95–3.6) .072 2.99 (1.54–5.81) .001
 Not insured Referent
Primary residence location
 Pacific 0.49 (0.15–1.61) .24 0.43 (0.13–1.44) .171 0.65 (0.19 −2.23) .493
 Mountain 0.3 (0.09–1.02) .053 0.33 (0.09–1.18) .089 0.48 (0.13–1.7) .254
 West South Central 0.31 (0.09–1.1) .07 0.27 (0.07–0.99) .048 0.36 (0.1–1.31) .12
 East South Central 0.4 (0.09–1.81) .237 0.46 (0.1–2.12) .316 0.55 (0.12–2.57) .444
 South Central 0.45 (0.13–1.5) .193 0.45 (0.13–1.55) .204 0.46 (0.13–1.6) .221
 West North Central 0.5 (0.12–2) .326 0.39 (0.09–1.61) .191 0.47 (0.11–1.99) .307
 East North Central 0.51 (0.14–1.79) .292 0.42 (0.12–1.53) .189 0.54 (0.15–1.96) .347
 Middle Atlantic 0.49 (0.14–1.8) .285 0.47 (0.13–1.75) .259 0.71 (0.19–2.68) .612
 New England Referent
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RRR = Relative risk ratio.

Final multivariable multinomial logistic regression model

All the 7 explanatory variables were retained in the final model, and these included respondent’s age (P < .001), education level (P < .001), annual pretax income (P < .001), pedigree status (single breed vs mixed breed) of dog owned (P < .001), dog insurance status (P < .001), primary residence location (P < .001), and sex of dog owned (P < .035; Table 5). No confounders were identified during the modeling process, and no significant interactions were found. In this multinomial model, the outcome variable categories “vaccinated as recommended by a veterinarian,” “vaccinated only against rabies,” “vaccinated as a puppy but not as an adult,” and “did not know vaccination status” are each compared to the referent level “not vaccinated.”

Table 5—

Associations between explanatory variables with vaccination status at the time of enrollment into the Dog Aging Project from the final multivariable multinomial logistic regression model.

Vaccinated as recommended Rabies only Vaccinated as a puppy
Characteristic RRR (95% CI) P value RRR (95% CI) P value RRR (95% CI) P value
Age of owner (y)
 > 75 0.28 (0.06–1.45) .13 1.76 (0.30–10.19) .529 0.56 (0.10–3.28) .524
 65–74 0.28 (0.06–1.20) .086 1.44 (0.29–7.10) .653 0.87 (0.18–4.21) .863
 55–64 0.23 (0.05–1.00) .05 1.24 (0.26–6.05) .788 0.83 (0.17–3.97) .816
 45–54 0.3 (0.07–1.33) .113 1.55 (0.31–7.90) .595 1.03 (0.21–5.14) .971
 35–44 0.29 (0.06–1.29) .103 1.07 (0.21–5.44) .936 0.99 (0.20–4.95) .993
 25–34 0.73 (0.15–3.59) .702 1.93 (0.35–10.75) .451 1.47 (0.27–8.12) .6476
 18–24 Referent
Education level
 Doctorate 7.89 (1.89–32.88) .005 3.29 (0.77–14.08) .109 2.48 (0.57–10.69) .224
 Professional 4.49 (1.58–12.76) .005 2.01 (0.69–5.91) .202 1.48 (0.5–4.39) .476
 Master’s degree 2.78 (1.65–4.70) < .001 1.70 (0.99–2.93) .056 1.22 (0.70–2.11) .487
 Bachelor’s degree 2.77 (1.73–4.44) < .001 2.19 (1.34–3.57) .002 1.71 (1.05–2.79) .033
 Less than bachelor’s degree Referent
Owner annual pretax income
 Preferred not to answer 6.20 (2.71–14.22) < .001 2.73 (1.13–6.58) .026 3.22 (1.31–7.94) .011
 $180,000 or more 6.74 (2.9–15.60) < .001 1.78 (0.73– 4.35) .207 2.38 (0.95–5.93) .063
 $160,000–$179,999 11.35 (2.49–51.86) .002 2.84 (0.59–13.75) .194 3.41 (0.69–16.77) .131
 $140,000–$159,999 6.79 (2.32–19.78) < .001 2.41 (0.78–7.41) .126 3.29 (1.05–10.28) .041
 $120,000–$139,999 13.87 (3.84–50.12) < .001 5.15 (1.37–19.41) .015 6.43 (1.68–24.56) .007
 $100,000–$119,999 7.62 (3.03–1907) < .001 2.71 (1.03–7.15) .044 3.28 (1.22–8.81) .019
 $80,000–$99,999 4.48 (2.02–9.91) < .001 1.94 (0.83–4.55) .125 2.27 (0.95–5.44) .065
 $60,000–$79,999 7.75 (3.2–18.70) < .001 3.19 (1.23–8.11) .014 4.53 (1.75–11.694) .002
 $40,000–$59,999 5.24 (2.32–11.85) < .001 2.25 (0.94–5.39) .067 3.22 (1.32–7.83) .01
 $20,000–$39,999 2.03 (0.98–4.22) .057 1.34 (0.61–2.97) .61 1.49 (0.66–3.39) .333
 < $20,000 Referent
Sex of dog owned
 Female 0.59 (0.4–0.89) .009 0.62 (0.41–0.92) .019 0.64 (0.43–0.96) .031
 Male Referent
Pedigree status of dog owned
 Multiple (mixed) breed 1.17 (0.79–1.71) .423 1.01 (0.68–1.49) .969 0.53 (0.35–0.79) .002
 Single breed Referent
Dog insurance status
 Insured 2.15 (1.12–4.16) .022 1.64 (0.83–3.22) .152 2.48 (1.26–4.85) .008
 Not insured Referent
Primary residence location
 Pacific 0.52 (0.16–1.72) .283 0.44 (0.13–1.50) .192 0.69 (0.20–2.36) .551
 Mountain 0.36 (0.11–1.26) .11 0.37 (0.11–1.32) .128 0.56 (0.16–2.00) .371
 West South Central 0.37 (0.11–1.31) .124 0.31 (0.085–1.12) .075 0.42 (0.11–1.54) .189
 East South Central 0.52 (0.12–2.34) .393 0.55 (0.12–2.57) .446 0.69 (0.14–3.25) .634
 South Central 0.48 (0.14–1.62) .237 0.47 (0.13–1.61) .227 0.49 (0.14–1.71) .262
 West North Central 0.61 (0.15–2.44) .482 0.43 (0.10–1.81) .252 0.53 (0.13–2.23) .386
 East North Central 0.64 (0.18–2.25) .484 0.48 (0.13–1.75) .268 0.62 (0.17–2.28) .475
 Middle Atlantic 0.53 (0.14–1.92) .33 0.49 (0.13–1.83) .287 073 (0.19–2.75) .639
 New England Referent
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Compared to dogs of respondents with an education level less than a bachelor’s degree, dogs of respondents with a doctorate were 7.89 times (95% CI, 1.89 to 32.88) more likely to be vaccinated as recommended by the veterinarian rather than to be not vaccinated, controlling for other factors. Similarly, dogs of respondents with a professional degree compared to those of respondents with less than a bachelor’s education level were significantly more likely (RRR, 4.49; 95% CI, 1.58 to 12.76) to be vaccinated per the veterinarian’s recommendation rather than to be not vaccinated (Table 5). When compared with those of less than a bachelor’s level of education, dogs of respondents with a master’s degree were more likely (RRR, 2.78; 95% CI, 1.65 to 4.70) to be vaccinated as recommended by the veterinarian rather than not to be vaccinated. Dogs of respondents with a bachelor’s degree compared to those of respondents with less than a bachelor’s education level were more likely (RRR, 2.77; 95% CI, 1.73 to 4.44) to be vaccinated per the veterinarian’s recommendations rather than not to be vaccinated.

Compared to dogs of respondents with an annual income less than $20,000, dogs of respondents with an annual income of $40,000 or more were significantly more likely to be vaccinated as recommended by the veterinarian rather than not to be vaccinated, controlling for other factors. Controlling for other factors, insured dogs compared to uninsured dogs were significantly more likely (RRR, 2.15; 95% CI, 1.12 to 4.16) to be vaccinated as recommended by the veterinarian rather than not to be vaccinated (Table 5).

Discussion

This study found that most dogs enrolled in the DAP were vaccinated in accordance with the veterinarian’s recommendations. It is possible that the small population that had not vaccinated per the veterinarian’s recommendations or did not vaccinate their dogs assumed that vaccinations are no longer necessary or are unnecessary10 since the impacts of infectious diseases in well-vaccinated populations have been mitigated through herd immunity.1 It is also possible that the population that did not vaccinate as recommended or had not vaccinated their dogs were vaccine hesitant as has been reported elsewhere.9

Despite the high self-reported adherence to the veterinarian’s recommendations, it is important that pet owners who do not adhere to recommended vaccinations are educated on the benefits of routine vaccination of dogs for patient protection and public health. It is also important that owners are continuously educated about vaccine safety and efficacy. A study21 conducted in the UK found that veterinarians are the most important source of information on vaccination for dog owners. Given the high level of adherence to veterinarian’s vaccine recommendations in this population, it is important that US veterinarians in clinical practice are aware of their significant influence on the dog owner’s decision to vaccinate. This knowledge could be used to increase dog vaccine uptake via enhanced client education.21

In the present study, age of the respondent, education level, annual pretax income, pedigree status of dog owned, dog insurance status, and primary residence location were identified as significant factors associated with the dog’s vaccination status. Similar to ours, a UK study7 found that insurance status and pedigree status of dogs were associated with variations in vaccine uptake and that vaccination rates were higher for insured and purebred dogs. Our study found that dogs of respondents with a bachelor’s degree or higher level of education were more likely to be vaccinated as recommended by the veterinarian when compared to those with less than a bachelor’s degree level of education. Respondents with a bachelor’s degree or more level of education are, perhaps, more scientifically literate and may understand the role of vaccinations in pet health, quality of life, and preventing zoonotic diseases. This key finding suggests that vaccine literacy programs targeting dog owners with lower than a bachelor’s level of education may be necessary. Vaccine literacy programs aimed at providing vaccine information, building communication, and increasing people’s engagement about vaccines22 have been shown to play an important role in increasing vaccine uptake.23

Our study found that dogs of respondents with an annual income of $40,000 or more were significantly more likely to be vaccinated as recommended by the veterinarian rather than not to be vaccinated, controlling for other factors. This finding may indicate that uptake of dog vaccinations in the US may depend upon the socioeconomic status of the owners. However, there is a need for more studies evaluating this association in the wider population of US dog owners because the present study was largely representative of respondents with higher annual pretax income and may not be generalizable to the rest of the US dog-owning population. Measures that aim to increase dog vaccine uptake among low-income pet owners may be necessary for addressing disparities in dog vaccine uptake between low-income and higher-income owners.

In the US, canine rabies vaccination, including the age at initial vaccination and timing of booster doses, is mandated by law in many jurisdictions due to the public health risk.1 The age at primary vaccination is a minimum of 3 months, with a booster vaccination annually (for vaccines whose duration of immunity lasts 1 year) or a second dose after 1 year and then boosted triennially (for vaccines with a duration of immunity lasting 3 years) depending on the licensed and marketed vaccine product.24 In the present study, most (92.2%) respondents vaccinated their dogs against rabies either annually (22.4% of overall) or less frequently than annually (69.8% of overall). The answer option for less frequently than annually was framed as “receives less frequently than annually (eg, every 3 years).” The large number of respondents choosing these 2 options across the different census regions suggests that there is a high level of adherence to the recommended rabies vaccination schedules. Similar to ours, a 2023 study25 that assessed vaccine hesitancy and support for vaccination requirements for pets in the US found that most dogs were vaccinated, with 93.8% of owners indicating their dogs were vaccinated against rabies. In the present study, the small number that chose the option “more than twice annually” could have done so out of recall bias since rabies vaccines are boosted either annually or triennially after the second dose. The small number of respondents who vaccinated previously but not since or never vaccinated could be either vaccine hesitant, unaware of the mandatory requirement to vaccinate/boost dogs against rabies, or constrained by other factors. The recommended vaccination schedules for canine distemper, adenovirus, and parvovirus are at least 3 doses of the combination vaccine between 6 and 16 weeks of age administered 2 to 4 weeks apart if the dog is aged ≤ 16 weeks of age or 2 doses of a combination vaccine administered 2 to 4 weeks apart for older dogs, followed by a single dose of a combination vaccine within 1 year after the last dose in the initial series and subsequent boosters administered triennially.1 In the present study, 50% of all the 2023 AFUS respondents used the distemper combination vaccine annually, 26% less frequently than annually (eg, every 3 years), 21% previously but not since, 0.5% never received, and 1.6% were unsure. These findings suggest that about 20% of the dogs in this cohort may not be up to date for distemper, adenovirus, and parvovirus vaccines, which are considered core vaccines that all dogs, irrespective of lifestyle, geographic location, and risk of exposure, should receive. Perhaps the costs associated with these vaccines were prohibitive.

Before 2024, the American Animal Hospital Association recommended that, depending on lifestyle, geographic region, and risk of exposure, 2 doses of Leptospira vaccine should be given to dogs ≤ 16 weeks of age 2 to 4 weeks apart starting at 12 weeks of age, and dogs aged > 16 weeks should receive 2 doses 2 to 4 weeks apart and then a single dose 1 year after the last dose, followed by annual boosters.1 In the present study, 55% of the respondents mentioned that Leptospira vaccines were given annually, and Middle Atlantic, East North Central, and South Atlantic regions had more than 10% of the respondents indicate annual vaccination against leptospirosis when compared to other census regions. This showed that Leptospira vaccination levels varied by US census region at the time these data were collected. Variation in canine Leptospira vaccine uptake was also found across the 12 regions of the UK.26 In the present study, some dogs were also not up to date for Leptospira vaccines given that at least 10% or more respondents from East North Central, South Atlantic, Mountain, and Pacific census regions mentioned that their dogs previously received a Leptospira vaccine but not since. In all census regions, some dogs had never received Leptospira vaccines, perhaps due to vaccine hesitancy and concerns about vaccine adverse events,27 yet canine leptospirosis was found to be widespread in the US,28 with a wide geographic variation in the predicted risk.29 Now that Leptospira vaccines are currently considered core,5 veterinarians and other public health professionals should step up education of owners on the need to vaccinate dogs against this zoonotic pathogen. In the present study, 40% of all respondents mentioned that their dogs had never received the Lyme disease (B burgdorferi) vaccine, and the majority of the respondents whose dogs never received Lyme disease vaccine were from the Pacific census region. Perceived lower risk might be the reason that this high proportion of respondents had never vaccinated against Lyme disease. Our study found higher proportions of annual Lyme disease vaccination in the New England area, Middle Atlantic, and East North Central US, likely due the perceived high risk of exposure resulting from the endemic nature of this disease in these regions. Canine Lyme disease is prominently clustered in the Northeastern US (which includes New England and Middle Atlantic) and Upper Midwest,30 and increases in its prevalence were found in both endemic and nonendemic regions of the US.31

Canine infectious respiratory disease complex, commonly known as kennel cough,32,33 is a contagious respiratory disease of dogs with multiple etiologies, including B bronchiseptica, which may act as the primary pathogen.34 Vaccines against kennel cough agents are recommended to be administered to dogs at risk of exposure as a single dose with subsequent annual boosters if the B bronchiseptica and canine parainfluenza virus combination vaccine is used and 2 doses 2 to 4 weeks apart followed by a single dose within 1 year of the initial series with subsequent annual boosters if the B bronchiseptica–only vaccine is used.1 In this study, annual vaccination against at least some kennel cough agents was reported by 53% of all the respondents, with 7.6% indicating that their dogs never received the kennel cough vaccine. Comparing these findings to those of others, a previous US study8 found that 64.6% of dogs in the study population from across the country were current for B bronchiseptica vaccination, with a median clinic vaccination rate of 68.7%. Canine influenza is a viral respiratory disease of dogs that emerged in the US in early 2015,35 and several outbreaks were reported between 2015 and 2017 based on positive samples from across the US.36 The American Animal Hospital Association1 currently recommends that, based on lifestyle, geographic location, and risk of exposure, 2 doses of the canine influenza vaccine should be administered to dogs 16 weeks or older 2 to 4 weeks apart, followed by a single dose 1 year after the initial dose series and subsequent boosters annually. In the present study, a relatively smaller proportion (29% of overall) reported vaccinating against canine influenza virus annually, 32% never vaccinated, and 21% were unsure. These results are possibly due to the noncore nature of this vaccine since noncore vaccines may be perceived to be optional.8 Similar to this present study, a previous study8 in the US that investigated noncore vaccination rates in dogs and cats found a median clinic vaccination proportion of only 4.5% for canine influenza. A previous US study suggested that other than disease risk, several factors, like the inherent challenges associated with individual patient risk assessment, may contribute to the variability in noncore vaccine uptake in dogs.8

Despite the large size of the DAP dataset, our results may still have limitations. First, selection bias could be an issue in this study because participants self-selected and volunteered to enroll in the study. Given the nature of this study, it is possible that people who sign up for DAP are more likely to pursue health-promoting behaviors, like vaccinations, for their pets, hence biasing the results away from the null. The majority of participants in this study generally had more years of education and higher incomes compared to the US as a whole.17 The results of this study may therefore not be generalize to the entire US population of dog owners. Second, the survey was electronic, requiring access to the internet, and this could have led to selection bias as well. Third, it is possible that the respondents provided socially desirable answers to the questions regarding their vaccination practices. However, despite these potential limitations, the findings of this study provide useful insights into the level of adherence of US pet owners to vaccination recommendations for dogs.

This study found a high level of compliance with veterinarian-recommended vaccinations among study participants. Dog vaccine uptake was higher among respondents with a bachelor’s degree or higher education level and among those with higher annual incomes. Vaccine literacy programs targeting dog owners with lower than a bachelor’s level of education and measures that aim to increase dog vaccine uptake among low-income pet owners may be necessary. Further research into the factors influencing the nonadherence and lack of uptake is needed to inform efforts that aim to increase vaccine uptake in dog populations.

Acknowledgments

The Dog Aging Project Consortium comprises Dr. Ruple and the following authors of this report: Joshua M. Akey, PhD (Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ); Brooke Benton, MPH (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA); Elhanan Borenstein, PhD (Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel; and Santa Fe Institute, Santa Fe, NM); Marta G. Castelhano, DVM, MVSc (Cornell Veterinary Biobank, College of Veterinary Medicine, Cornell University, Ithaca, NY); Amanda E. Coleman, DVM, DACVIM (Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA); Kate E. Creevy, MS, DVM, DACVIM (Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX); Matthew D. Dunbar, PhD (Center for Studies in Demography and Ecology, University of Washington, Seattle, WA); Virginia R. Fajt, PhD, DVM, DACVCP (Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX); Annette L. Fitzpatrick, PhD (Department of Family Medicine, University of Washington, Seattle, WA; Department of Epidemiology, University of Washington, Seattle, WA; and Department of Global Health, University of Washington, Seattle, WA); Erica C. Jonlin, PhD (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA; and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA); Matt Kaeberlein, PhD (Optispan, Inc., Seattle, WA); Elinor K. Karlsson, PhD (Bioinformatics and Integrative Biology, Chan Medical School, University of Massachusetts, Worcester, MA; and Broad Institute of MIT and Harvard, Cambridge, MA); Kathleen F. Kerr, PhD (Department of Biostatistics, University of Washington, Seattle, WA);Jing Ma, PhD (Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA); Evan L. MacLean, PhD (College of Veterinary Medicine, University of Arizona, Tucson, AZ); Daniel E. L. Promislow, PhD (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA; and Department of Biology, University of Washington, Seattle, WA); Stephen M. Schwartz, PhD (Department of Epidemiology, University of Washington, Seattle, WA; and Epidemiology Program, Fred Hutchinson Cancer Research Center, Seattle, WA); Sandi Shrager, MSW (Department of Biostatistics, Collaborative Health Studies Coordinating Center, University of Washington, Seattle, WA); Noah Snyder-Mackler, PhD (School of Life Sciences, Arizona State University, Tempe, AZ; Center for Evolution and Medicine, Arizona State University, Tempe, AZ; and School for Human Evolution and Social Change, Arizona State University, Tempe, AZ); M. Katherine Tolbert, PhD, DVM, DACVIM (Department of Small Animal Clinical Sciences, Texas A&M University School of Veterinary Medicine & Biomedical Sciences, College Station, TX); and Silvan R. Urfer, DMV (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA).

Funding

The Dog Aging Project was supported by U19 grant No. AG057377 from the National Institute on Aging, a part of the NIH, and by private donations. The preparation of this manuscript was funded by the Center for Outcomes Research and Epidemiology and the Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Footnotes

Disclosures

The authors have nothing to disclose. No AI-assisted technologies were used in the composition of this manuscript.

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