Disrupted Routine Medical Visits in Children and Adolescents During the COVID-19 Pandemic, January–June 2021

HIGHLIGHTS

• •Disruption of medical visits occurred among children during the first half of 2021.
• •COVID-19 affected non-White children and families with lower income.
• •COVID-19 affected children whose mother had less than a college education.
• •Efforts are needed by healthcare providers to make catch-up vaccination a priority.

Abstract

Introduction

Recent studies have indicated the COVID-19 pandemic has disrupted routine vaccinations. This study describes the prevalence and characteristics of children and adolescents experiencing disrupted routine vaccination and other medical visits in the U.S. between January and June 2021.

Methods

The National Immunization Surveys were the source of data for this cross-sectional analysis (n=86,893). Parents/guardians of children aged between 6 months and 17 years were identified through random-digit dialing of cellular phone numbers and interviewed. Disrupted visits were assessed by asking: In the last 2 months, was a medical checkup, well-child visit, or vaccination appointment for the child delayed, missed, or not scheduled for any reason? Respondents answering yes were asked: Was it because of COVID-19? Sociodemographic characteristics of children/adolescents with (1) COVID-19–related missed visits and (2) non-COVID-19–related missed visits were examined. Statistical differences within demographic subgroups were determined using t-tests, with p-values <0.05 considered statistically significant. Linear regression models were used to examine the trends in disrupted visits over time.

Results

An estimated 7.9% of children/adolescents had a missed visit attributed to COVID-19; 5.2% had a missed visit that was not COVID-19–related. Among children/adolescents with a COVID-19–related missed visit, a higher percentage were of minority race or ethnicity, lived below the poverty level, had a mother without a college degree, and lived in the western U.S. There was a significant decline in the COVID-19–related missed visits over time.

Conclusions

COVID-19 disrupted routine vaccination or other medical visits inequitably. Catch-up immunizations are essential for achieving adequate vaccination of all children/adolescents.

INTRODUCTION

The impact of vaccinations on the health of communities worldwide has been vast. Vaccination has been referred to as one of the 10 greatest public health achievements of the 20^th century.¹ This simple course of action effectively prevents an individual from acquiring harmful and potentially deadly diseases. Since the administration of vaccinations began, there has been a notable decline in vaccine-preventable diseases (VPD), with an estimated 100 million VPD cases being averted within the U.S. through this intervention² One analysis of data from the National Immunization Survey (NIS) of cohorts of children born between 1994 and 2013 estimated that vaccinations will prevent 322 million illnesses, 21 million hospitalizations, and 732,000 deaths over the course of their lifetimes.³

Lower vaccination coverage can result from barriers preventing families from accessing immunizations. These barriers include, among others, a poor understanding of the effectiveness of vaccinations, failure to comprehend the importance of following vaccination schedules, lack of transportation, difficulty taking time off work, and cost.⁴ Parents and guardians may face additional challenges, such as the need for child care, which places them at a disadvantage and decreases the chance of their family being fully vaccinated.⁵ There are also segments of the population that are not protected from VPDs because of their distrust of vaccines. These individuals tend to either delay or completely refuse to receive any vaccinations for themselves and their children.⁴ This hesitation often stems from a concern about the vaccine's safety and their potential side effects.⁶ With the emergence of coronavirus disease 2019 (COVID-19), there is now an additional barrier disrupting the vaccination process. Recent studies have indicated that the COVID-19 pandemic has disrupted routine vaccinations.7, 8, 9, 10

The purpose of this study was to use data from the NIS to examine missed, delayed, and not scheduled vaccination and other medical visits among children and adolescents in the U.S. from January to June 2021. We characterized these missed visits as either COVID-19–related or non-COVID-19–related. We also examined the trends in the missed visits over time.

METHODS

Study Population

The NIS are a family of random-digit-dialed telephone surveys to monitor vaccination coverage in children aged 19–35 months (NIS-Child), adolescents aged 13–17 years (NIS-Teen), and influenza vaccination coverage in children aged 6–18 months and 3–12 years; ages not eligible for either NIS-Child or NIS-Teen (NIS-CIM). Between January and June 2021, questions on delayed, missed, or not scheduled vaccination or other medical visits during the pandemic were added to these 3 surveys. The responses were combined to allow the examination of disrupted medical visits for children aged between 6 months and 17 years.

Measures

The main focus of this study was to assess vaccinations or other medical visits missed because of delayed, skipped, or not scheduled appointments. A not scheduled appointment is a medical visit that the child was due for, but the parent did not schedule. To examine the disruption in the rates of vaccination or other medical visits, respondents were asked the following: In the last 2 months, was a medical checkup, well-child visit, or vaccination appointment for the child delayed, missed, or not scheduled for any reason? Respondents answering yes were further asked: Was the child's visit or appointment delayed, missed, or not scheduled because of COVID-19? These 2 questions were combined to operationalize the outcome into 3 categories: those who had COVID-19–related missed visits, those who had non-COVID-19–related missed visits, and those who did not miss any visits in the previous 2 months. The interview completion month was used to examine the trends in missed, delayed, or not scheduled visits over time, from January 15 to June 30, 2021.

Disparities in disrupted routine visits were examined by age (6–23 months, 2–4 years, 5–8 years, 9–12 years, and 13–17 years), race/ethnicity (Hispanic, non-Hispanic White, non-Hispanic Black, non-Hispanic American Indian/Alaska Native, non-Hispanic Asian, non-Hispanic Native Hawaiian/other Pacific Islander, and non-Hispanic multiracial/other), sex of the child (male or female), and among those aged between 13–17 years, whether the adolescent had any chronic medical conditions, including lung conditions other than asthma, heart conditions, diabetes, kidney conditions, sickle cell anemia or other anemia, or weakened immune system caused by a chronic illness or by medicines taken for a chronic illness (yes or no). Household demographics included poverty status (income >$75,000 and at or above poverty level, income ≤$75,000 and at or above poverty level, income below poverty level, and unknown), mother's education level (less than high school, high school graduate, some college, and college graduate), and the language used to conduct the interview (English, Spanish, and other).

Geographic variables included metropolitan statistical area (MSA) status (MSA principal city, MSA nonprincipal city, and non-MSA), census region (Northeast, Midwest, South, and West), and the state of residence (all 50 states and Washington, DC). The authors also included some select analyses for U.S. territories (Guam, Puerto Rico, and the U.S. Virgin Islands), although these data were not included in the national estimates.

Statistical Analysis

The sample was weighted to be representative of the U.S. population, and all analyses were conducted using SAS-callable SUDAAN (version 11.0; RTI International). Linear regression models were used to examine the trends in disrupted visits over time. Statistical differences in the proportion of missed visits between demographic and geographic subgroups were determined through t-tests, with p-values <0.05 considered statistically significant. The NIS-Teen was reviewed by the Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Disease human subjects contact and determined to be surveillance, so IRB review was not required. However, CDC's NIS contractor, NORC at the University of Chicago, had their own IRB review.

RESULTS

A total of 101,806 parents or guardians with age-eligible children were interviewed from January to June 2021. Of these, 9,006 (8.8%) either did not know the answer to the questions regarding missed or delayed medical and vaccination visits, or refused to answer and hence were excluded from the analysis. The final sample incorporates data from 86,893 children and adolescents residing in the 50 states and Washington, DC, in the U.S. The authors also analyzed the data from an additional 5,907 children/adolescents living in Puerto Rico, Guam, and the U.S. Virgin Islands, although these data were not included in the national estimates.

Characteristics of the children and adolescents in the analysis are shown in Table 1. Approximately 13.1% were reported to have missed at least 1 medical checkup, well-child visit, or vaccination appointment within the previous 2 months, with 7.9% having missed visits because of COVID-19. Most of the children/adolescents were non-Hispanic White (50.5%); distribution by sex was nearly equal. The proportion of children/adolescents was 6.5% for ages 6–23 months, 17.1% for ages 2–4 years, 23.3% for ages 5–8 years, 23.0% for ages 9–12 years, and 30.1% for ages 13–17 years. Among adolescents aged 13–17 years, 22.3% had a chronic medical condition. Most children/adolescents (73.1%) had household incomes at or above the poverty level, and nearly half (47.5%) had mothers who were college graduates. Interviews were almost entirely conducted in English (93.3%). Most children/adolescents (62.8%) lived in MSA nonprincipal cities, and a substantial portion (39.0%) lived in the southern region of the U.S.

Table 1.

Characteristics of Children and Adolescents—NIS, U.S., January–June 2021

Characteristic	n	Weighted % (95% CI)
Nationala	86,893	100
Missed visits in previous 2 months
Yes, COVID-19–related	6,906	7.9 (7.6, 8.3)
Yes, non-COVID-19–related	4,310	5.2 (4.9, 5.5)
No	75,677	86.8 (86.4, 87.3)
Race/ethnicity
Hispanicb	15,993	25.3 (24.7, 25.9)
Non-Hispanic White	49,460	50.5 (49.9, 51.2)
Non-Hispanic Black	9,302	13.6 (13.2, 14.1)
Non-Hispanic American Indian/Alaska Native	1,137	0.7 (0.6, 0.8)
Non-Hispanic Asian	4,461	4.9 (4.6, 5.2)
Non-Hispanic Native Hawaiian/other Pacific Islander	583	0.3 (0.3, 0.4)
Non-Hispanic multiracial/other	5,951	4.6 (4.3, 4.8)
Sex
Female	41,717	48.9 (48.3, 49.6)
Male	45,176	51.1 (50.4, 51.7)
Age group
6–23 months	8,321	6.5 (6.2, 6.8)
2–4 years	19,285	17.1 (16.6, 17.5)
5–8 years	16,897	23.3 (22.7, 23.9)
9–12 years	20,447	23.0 (22.5, 23.6)
13–17 years	21,943	30.1 (29.4, 30.7)
Chronic medical conditionc (n=20,981)
Yes	4,568	22.3 (21.2, 23.4)
No	16,413	77.7 (76.6, 78.8)
Poverty statusd
At or above poverty level, income >$75,000	42,449	46.4 (45.7, 47.0)
At or above poverty level, income ≤$75,000	23,570	26.7 (26.1, 27.2)
Below poverty level	10,436	13.6 (13.2, 14.1)
Unknown	10,438	13.3 (12.9, 13.8)
Mother's education level
<High school	5,104	7.1 (6.7, 7.4)
High school graduate	13,953	16.4 (15.9, 16.9)
Some college	20,748	23.7 (23.1, 24.2)
College graduate	42,727	47.5 (46.9, 48.1)
Unknown	4,361	5.3 (5.0, 5.6)
Language of interview
English	82,804	93.3 (92.9, 93.6)
Spanish	3,298	5.7 (5.4, 6.1)
Other language	791	1.0 (0.9, 1.2)
MSA statuse
MSA, principal city	23,074	26.0 (25.4, 26.6)
MSA, nonprincipal city	50,220	62.8 (62.2, 63.4)
Non-MSA	13,599	11.2 (10.8, 11.5)
Census region
Northeast	17,791	15.8 (15.4, 16.2)
Midwest	17,105	21.1 (20.6, 21.6)
South	31,983	39.0 (38.4, 39.7)
West	20,014	24.1 (23.5, 24.7)

^aExcludes respondents who did not provide data on missed visits (n=9,006) and those residing in the U.S. territories of Guam (n=1,423), Puerto Rico (n=3,423), and the U.S. Virgin Islands (n=1,061).

^bHispanic children/adolescents may be of any race.

^cChronic medical conditions were assessed only among adolescents aged 13–17 years. Conditions included: lung condition other than asthma, heart condition, diabetes, kidney condition, sickle cell anemia or other anemia, or weakened immune system caused by a chronic illness or by medicines taken for a chronic illness.

^dChildren/adolescents were classified as below the federal poverty level if their total family income was less than the poverty threshold specified for the applicable family size and number of children aged <18 years. Poverty level was based on 2017–2019 U.S. Census poverty thresholds (www.census.gov/data/tables/time-series/demo/income/poverty/historical-poverty-thresholds.html).

^eMSA status was determined based on household-reported county and city of residence and was grouped into 3 categories: MSA principal city, MSA nonprincipal city, and non-MSA. MSA and principal city were as defined by the U.S. Census Bureau (https://www.census.gov/programs-surveys/metro-micro.html). Non-MSA areas include urban populations not located within an MSA as well as completely rural areas.

MSA, Metropolitan statistical area; NIS, National Immunization Surveys.

Table 2 provides prevalence ratios describing the association between child/adolescent characteristics and COVID-19–related and non-COVID-19–related missed visits.

Table 2.

Association of Characteristics of Children/Adolescents With Missed Routine Visits, NIS, U.S., January–June 2021

	No missed visits		Missed visits COVID-19–related			Missed visits non-COVID-19–related
Characteristic	n	Weighted % (95% CIs)	n	Weighted % (95% CIs)	Prevalence ratio (95% CIs)	n	Weighted % (95% CIs)	Prevalence ratio (95% CIs)
National	75,677	86.8 (86.4, 87.3)	6,906	7.9 (7.6, 8.3)		4,310	5.2 (4.9, 5.5)
Race/ethnicity
Hispanica	13,619	84.9 (83.8, 86.0)	1,524	9.2 (8.4, 10.1)	1.43 (1.27, 1.59)	850	5.9 (5.2, 6.6)	1.23 (1.05, 1.41)
Non-Hispanic White	43,779	88.7 (88.2, 89.3)	3,382	6.5 (6.1, 6.9)	ref	2,299	4.8 (4.4, 5.2)	ref
Non-Hispanic Black	7,837	83.9 (82.3, 85.3)	918	10.2 (8.9, 11.5)	1.57 (1.35, 1.79)	547	6.0 (5.1, 7.0)	1.25 (1.04, 1.47)
Non-Hispanic American Indian/Alaska Native	941	85.6 (81.5, 88.9)	128	10.6 (7.6, 14.7)	1.64 (1.10, 2.18)	68	3.8 (2.6, 5.5)	0.79 (0.50, 1.09)
Non-Hispanic Asian	3,865	86.1 (84.0, 87.9)	403	9.3 (7.8, 11.1)	1.44 (1.17, 1.70)	199	4.6 (3.6, 6.0)	0.97 (0.71, 1.23)
Non-Hispanic Native Hawaiian/other Pacific Islander	505	87.4 (80.0, 92.3)	42	6.2 (3.5, 10.7)	0.95 (0.42, 1.49)	36	6.4 (2.8, 14.3)	1.35 (0.24, 2.45)
Non-Hispanic multiracial/other	5,131	86.2 (84.2, 88.0)	509	8.3 (6.9, 10.0)	1.29 (1.03, 1.54)	311	5.5 (4.3, 6.9)	1.14 (0.87, 1.42)
Sex
Female	36,303	86.8 (86.1, 87.4)	3,341	7.9 (7.4, 8.4)	ref	2,073	5.3 (4.9, 5.8)	ref
Male	39,374	86.9 (86.3, 87.5)	3,565	8.0 (7.5, 8.5)	1.01 (0.92, 1.10)	2,237	5.1 (4.7, 5.6)	0.96 (0.85, 1.07)
Age group of child
6–23 months	7,119	84.9 (82.7, 86.8)	720	9.1 (7.5, 11.0)	1.42 (1.12, 1.72)	482	6.0 (4.9, 7.4)	1.16 (0.89, 1.44)
2–4 years	16,584	85.9 (84.9, 86.9)	1,745	8.9 (8.0, 9.8)	1.38 (1.19, 1.57)	956	5.2 (4.6, 5.9)	1.00 (0.84, 1.17)
5–8 years	14,667	86.3 (85.2, 87.2)	1,405	8.6 (7.8, 9.4)	1.34 (1.16, 1.51)	825	5.2 (4.6, 5.8)	1.00 (0.83, 1.16)
9–12 years	17,858	86.6 (85.6, 87.5)	1,601	8.2 (7.5, 9.0)	1.28 (1.11, 1.45)	988	5.2 (4.6, 5.8)	1.00 (0.84, 1.16)
13–17 years	19,449	88.4 (87.5, 89.2)	1,435	6.4 (5.8, 7.1)	ref	1,059	5.2 (4.6, 5.8)	ref
Chronic medical conditionb  (n=20,981)
Yes	4,005	87.7 (85.8, 89.3)	345	7.8 (6.4, 9.5)	1.30 (1.01, 1.59)	218	4.5 (3.6, 5.6)	0.84 (0.63, 1.05)
No	14,589	88.6 (87.6, 89.5)	1,025	6.0 (5.3, 6.7)	ref	799	5.4 (4.7, 6.1)	ref
Poverty statusc
At or above poverty level, income >$75,000	37,923	89.3 (88.7, 89.9)	2,752	6.3 (5.9, 6.8)	ref	1,774	4.4 (4.0, 4.8)	ref
At or above poverty level, income ≤$75,000	20,026	84.4 (83.5, 85.4)	2,215	9.3 (8.5, 10.0)	1.47 (1.31, 1.63)	1,329	6.3 (5.7, 7.0)	1.43 (1.24, 1.62)
Below poverty level	8,622	82.3 (80.7, 83.8)	1,144	11.3 (10.1, 12.6)	1.79 (1.55, 2.04)	670	6.4 (5.4, 7.4)	1.45 (1.19, 1.71)
Unknown	9,106	87.7 (86.4, 88.9)	793	7.5 (6.5, 8.6)	1.19 (1.01, 1.37)	537	4.8 (4.1, 5.6)	1.09 (0.89, 1.29)
Mother's education level
<High school	4,307	84.0 (81.9, 85.8)	479	9.8 (8.3, 11.5)	1.41 (1.16, 1.66)	313	6.2 (5.1, 7.6)	1.51 (1.17, 1.84)
High school graduate	11,804	84.4 (83.0, 85.6)	1,260	8.9 (7.9, 9.9)	1.27 (1.11, 1.44)	889	6.8 (5.9, 7.8)	1.64 (1.38, 1.91)
Some college	17,756	85.3 (84.2, 86.3)	1,799	8.7 (7.9, 9.5)	1.24 (1.10, 1.39)	1,193	6.1 (5.4, 6.7)	1.47 (1.26, 1.67)
College graduate	38,018	88.9 (88.3, 89.5)	3,020	7.0 (6.5, 7.5)	ref	1,689	4.1 (3.8, 4.5)	ref
Unknown	3,792	86.8 (84.6, 88.8)	348	7.8 (6.3, 9.7)	1.13 (0.88, 1.37)	221	5.3 (4.1, 6.9)	1.29 (0.93, 1.64)
Language of interview
English	72,172	86.9 (86.5, 87.4)	6,512	7.8 (7.4, 8.2)	ref	4,120	5.3 (5.0, 5.6)	ref
Spanish	2,828	84.9 (82.2, 87.2)	321	10.1 (8.2, 12.3)	1.29 (1.03, 1.56)	149	5.1 (3.6, 7.1)	0.96 (0.63, 1.29)
Other language	677	87.6 (83.2, 91.0)	73	7.5 (4.8, 11.4)	0.96 (0.54, 1.37)	41	4.9 (3.1, 7.8)	0.93 (0.50, 1.37)
Metropolitan statistical  area (MSA) statusd
MSA, principal city	19,919	86.0 (85.0, 86.9)	2,059	8.9 (8.1, 9.8)	ref	1,096	5.1 (4.5, 5.8)	ref
MSA, nonprincipal City	43,834	86.9 (86.3, 87.5)	3,918	7.8 (7.4, 8.3)	0.87 (0.78, 0.97)	2,468	5.3 (4.9, 5.7)	1.04 (0.89, 1.19)
Non-MSA	11,924	88.4 (87.3, 89.4)	929	6.3 (5.5, 7.1)	0.70 (0.59, 0.81)	746	5.3 (4.6, 6.1)	1.04 (0.85, 1.23)
Census region
Northeast	15,621	87.7 (86.7, 88.7)	1,437	8.2 (7.4, 9.1)	1.14 (0.99, 1.29)	733	4.1 (3.6, 4.7)	0.73 (0.61, 0.85)
Midwest	15,007	87.9 (86.9, 88.9)	1,190	6.7 (6.0, 7.5)	0.93 (0.81, 1.05)	908	5.4 (4.7, 6.1)	0.96 (0.81, 1.10)
South	27,845	87.2 (86.5, 87.9)	2,509	7.2 (6.7, 7.7)	ref	1,629	5.6 (5.2, 6.2)	ref
West	17,204	84.7 (83.6, 85.8)	1,770	10.1 (9.2, 11.0)	1.40 (1.24, 1.56)	1,040	5.2 (4.6, 5.9)	0.92 (0.78, 1.06)

Note: Boldface indicates statistical significance (p<0.05).

^aHispanic children/adolescents may be of any race.

^bChronic medical conditions were assessed only among adolescents aged 13–17 years. Conditions include lung condition other than asthma, heart condition, diabetes, kidney condition, sickle cell anemia or other anemia, or weakened immune system caused by a chronic illness or by medicines taken for a chronic illness.

^cChildren/adolescents were classified as below the federal poverty level if their total family income was less than the poverty threshold specified for the applicable family size and number of children aged <18 years. Poverty level was based on 2017–2019 U.S. Census poverty thresholds.

www.census.gov/data/tables/time-series/demo/income-poverty/historical-poverty-thresholds.html.

^dMSA status was determined based on household-reported county and city of residence and was grouped into 3 categories: MSA principal city, MSA nonprincipal city, and non-MSA. MSA and principal city were as defined by the U.S. Census Bureau (https://www.census.gov/programs-surveys/metro-micro.html). Non-MSA areas include urban populations not located within an MSA as well as completely rural areas.

MSA, Metropolitan statistical area; NIS, National Immunization Survey.

COVID-19–Related Missed Visits

Children/adolescents who were Hispanic, Black, American Indian/Alaska Native, Asian, or multiracial were more likely to have COVID-19–related missed visits than White children/adolescents. A larger proportion of children aged <13 years had COVID-19–related missed visits than adolescents aged 13–17 years. Among adolescents, the presence of a chronic medical condition was associated with a higher proportion of missed visits related to COVID-19. Missed visits because of COVID-19 were more common among children/adolescents living below poverty and those at or above the poverty level but with household income of ≤$75,000 than those from higher income households. Children/adolescents with mothers who were not college graduates were more likely to experience COVID-19–related missed visits than those of college-educated mothers. Interviews conducted in Spanish rather than English were associated with a higher prevalence of COVID-19–related missed visits. Subjects living in non-MSA areas or MSA nonprincipal cities were less likely to have experienced COVID-19–related missed visits than those living in MSA principal cities. Children and adolescents living in the western U.S. had a higher prevalence of missed visits because of COVID-19 than those living in the southern part of the country. The prevalence of COVID-19–related missed visits varied by jurisdiction, ranging from 3.2% in Nebraska to 12.1% in California. (Figure 1, Appendix Table 1).

Figure 1.

Distribution of COVID-19–related missed visits by state/territory of residence, NIS, U.S., January–June 2021.

Non-COVID-19–Related Missed Visits

Fewer associations were noted between child/adolescent characteristics and non-COVID-19–related missed vaccination or other medical visits. Hispanic and Black children/adolescents had a higher proportion of non-COVID-19–related missed visits than White children/adolescents. Children and adolescents living in households below the poverty level and those in households with an income at or above the poverty level but ≤$75,000 per year were more likely to have a non-COVID-19–related missed visits than those in households with a higher annual income. Non-COVID-19–related missed visits were more common among children and adolescents whose mothers had less than a college education. Children and adolescents living in the northeastern U.S. were less likely to have experienced missed visits not related to COVID-19 than those living in the southern part of the country. The prevalence of non-COVID-19–related missed visits varied by jurisdiction, ranging from 2.3% in Connecticut to 7.5% in Hawaii (Appendix Table 1). No associations were seen based on sex, age group, chronic medical conditions, language of interview, or MSA.

Monthly estimates of the percentage of children and adolescents with COVID-19–related and non-COVID-19–related missed visits from January to June of 2021 are shown in Figure 2. The proportion of missed visits because of COVID-19 decreased over the study period from a high of 10.2% to a low of 5.8 % (p-value <0.001). For non-COVID–related missed visits, the proportions did not change much over time (p-value=0.93) and were smaller than those for COVID-19–related missed visits at all points except for June 2021, when they were equal at 5.8%.

Figure 2.

COVID-19–related and non-COVID-19–related missed vaccination and other medical visits among children and adolescents, January–June 2021, NIS, U.S.

*Linear relationship between data collection month and percentage of children/adolescents with missed visits was estimated with weighted linear regression analysis using the inverse of the estimated variance of each point estimate to construct the weights. The p-values evaluate whether the slope of the linear regression lines differ from zero.

DISCUSSION

This study used a large nationally representative sample to examine the disparities in missed, delayed, and not scheduled vaccination and other medical visits among children and adolescents nationwide, and it examined the trends in these disrupted visits over time. These medical visits provide an opportunity for children and adolescents to remain healthy and up to date on immunizations. Physicians conducting these routine medical visits typically perform physical exams, track growth and developmental behavior, and discuss any necessary preventive health measures.

The findings of this study regarding disrupted visits revealed that during the first half of 2021, the COVID-19 pandemic disproportionately affected non-White children and adolescents as well as those from families with lower income. In addition, children aged <13 years and children/adolescents whose mothers had less than a college education were disproportionately impacted with COVID-19–related delayed, missed, or not scheduled visits. Although children and adolescents did miss some of their medical appointments owing to COVID-19, there was a significant decline in COVID-19–related disrupted visits from January to June 2021.

Several studies have sought to evaluate the impact of the COVID-19 pandemic on routine vaccinations in children and adolescents. The Michigan Care Improvement Registry reported a decline in vaccination coverage in most age groups.⁷ For example, the up to date status of children aged 5 months declined from two thirds in the years 2016–2019 to under half (49.7%) in May 2020. CDC reported a significant decrease in administered vaccine doses in children between the months of March and April 2020 compared with the same period during the years 2018 and 2019. Administered doses rebounded somewhat from June to September 2020 but did not reach the prepandemic levels.⁸ Another study projected the coverage of measles vaccine under various assumptions regarding the length of stay-at-home orders and catch-up vaccination efforts, and it suggested that a 15% catch-up rate might be needed to maintain coverage at prepandemic levels.⁹ An additional analysis used data from 8 health systems included in the Vaccine Safety Datalink and concluded that the proportion of children and adolescents that were up to date with their childhood vaccinations was lower in 2020 than the up to date rates during the comparable months in 2019.¹⁰ In terms of non-COVID-19–related missed visits, a prior study conducted a cross-sectional online survey of 2,074 U.S. parents with children aged ≤12 years, in an effort to determine the number of missed routine medical visits within the first 12 months of the COVID-19 pandemic. The study concluded with 41.3% of the participating parents reporting that their youngest child missed a routine medical visit during the first year of the COVID-19 pandemic.¹¹ However, these studies were conducted at an earlier stage of the pandemic when access to vaccine services was growing increasingly difficult because of stay-at-home orders and local health departments temporarily not offering routine vaccinations.¹² At this time, the pandemic was also still new to the public. It had been a century since a pandemic of this scale has occurred, and most of the public was unsure about how to proceed. This uncertainty impacted all the aspects of daily life, including routine vaccinations. In such an unusual time, some parents were either delaying or canceling their children's immunization visits altogether.¹² In just a year, social distancing and wearing masks became a part of daily life. This allowed some of the initial fear to subside and prompted many families to attempt to return to normal. The larger decrease in routine vaccination rates found in other studies is understandable, given the earlier timeframe of those studies.

However, this study indicates continued disruption of preventive care visits among children during the first half of 2021. The pandemic's ability to amplify disparities in vaccination or other medical visits of minority groups and vulnerable populations has been attributed to a more general inequitable access to high-quality health care.¹³ Having knowledge of this information allows for effective interventions to be developed to promote catch-up vaccination and ultimately diminish the impact COVID-19 may have on routine vaccinations.

The variation in COVID-19–related missed visits by state may reflect the differences in COVID-19 case rates and state-level policies being implemented in response to COVID-19–related morbidity and mortality. The severity of COVID-19 varied by state,¹⁴ and this may contribute to the variation observed in the missed COVID-19–related visits. Other reasons for the variation may be related to access and opportunity for telehealth visits¹⁵ and state policies such as mask mandates,16, 17, 18 stay-at-home orders,¹⁶ and restaurant COVID-19 operating guidance.^17,18

Limitations

This analysis has several limitations. First, the outcome of this study was based on parental self-report, and thus it is subject to recall bias. However, the questions asked to the respondents were in reference to the last 2 months, which would minimize recall error. Second, it is unknown if vaccinations were planned for the missed visits, so the impact of these missed visits on routine vaccination coverage could be overestimated. Third, a telehealth visit would not be classified as a missed visit, but it does not provide the opportunity for a vaccination. The impact of the variation in access to a telehealth visit is uncertain. Fourth, the question on disrupted visits was not asked before the pandemic, so the baseline rate of missed visits is unknown. Fifth, this analysis is descriptive and examines sociodemographic characteristics individually. Sixth, the data were weighted, but bias may remain after weighting adjustments to mitigate against incomplete sample frame (landline only or phone-less households) and nonresponse bias.

CONCLUSIONS

The American Academy of Pediatrics recommends a series of well-child visits at designated ages from infancy to adolescence.¹⁹ The schedule includes 5 well-child visits for children aged 6–23 months (at 6, 9, 12, 15, and 18 months) followed by annual visits for children aged 2–17 years. Recommended visits are more frequent for children aged <2 years, providing more opportunities for them to remain up to date on immunizations. Depending on age, high-risk status, and possible need for catch-up immunizations, a child may be eligible to receive ≥1 vaccines at any of these visits. A missed or skipped well-child visit at any age is a missed opportunity to ensure that the child or adolescent is up to date with age-appropriate immunizations.

The American Academy of Pediatrics comprehensive health guidelines for well-child/adolescent encounters also emphasize on tracking growth and physical as well as social development, addressing health or behavioral concerns raised by parents/guardians, and providing educational materials designed to optimize the physical, mental, and social health of the children and adolescents. Missing medical visits could therefore lead to delayed diagnosis of developmental and other health-related conditions, potentially interfering with implementing early interventions that are often associated with improved outcomes. A study conducted on more than 50,000 healthcare providers examined visit volume from the start of the COVID-19 pandemic to the end of 2020.²⁰ In-person visits dropped dramatically from early March until early April and began to rebound in mid to late April; although visits to most physicians, including pediatricians, remained well below baseline. The observed rebound coincided with a dramatic increase in telemedicine visits, which is considered one of the most important adaptations by medical professionals to the challenges posed by the pandemic. Telemedicine visits could be useful in accomplishing some, but not all, of the goals of well-child visits, with immunizations representing one of the major activities that cannot be achieved in the absence of an in-person provider visit.

The NIS and other data sources will be used in future analyses to assess the full impact of COVID-19 on routine vaccination of children. This study indicates that disruptions in health care continued in early 2021, and they disproportionately affected children from racial and ethnic minority groups, those living below poverty, and those living in certain states. Efforts are needed by healthcare providers to build trust with the parents and children they serve, remind them of upcoming or overdue vaccinations, discuss the protocols taken to ensure the safety of patients, and make catch-up vaccination efforts a priority.¹⁰