Visit types and linkage to HIV prevention among individuals seeking mpox vaccination in an urban specialized sexual health clinic

Abstract

Individuals attending mpox vaccine-only visits at an STI clinic were more likely to be new patients with high socioeconomic status and identify as White than those vaccinated during non-mpox related visits. A small number received HIV PrEP or testing following vaccination; this may represent a missed opportunity for HIV prevention.

Summary:

A study of mpox vaccination at an STI clinic found significant demographic differences between individuals vaccinated during vaccine-only visits vs routine clinic visits. Some patients received HIV prevention following vaccination.

Introduction

The US response to the global outbreak of Mpox disease included rapid distribution of vaccination to individuals at increased risk, primarily men who have sex with men (MSM)¹. However, delivery of mpox interventions, including vaccination, was inequitable. In Massachusetts (MA), vaccine administration data reveal that while Black and Hispanic populations comprise nearly half of mpox cases, these groups constitute just 20% of those vaccinated for mpox².

Similar racial-ethnic disparities have been noted in access to and use of HIV pre-exposure prophylaxis (PrEP)³. The mechanisms by which inequities in mpox vaccination delivery mirror those in HIV prevention access are not well understood. Further, it is unclear if these public health interventions primarily targeting MSM were used together, and whether disparities in PrEP access may have been perpetuated in the mpox vaccination effort.

Conversely, vaccination efforts may have improved overall uptake of HIV preventative care by increasing care engagement. We aim to understand patterns of mpox vaccine access and subsequent linkage to HIV prevention in a sexual health clinic that offered mpox vaccine-only appointments.

Methods

We used electronic medical record data to identify individuals aged ≥18years who received at least one dose (first or second) of mpox vaccine (JYNNEOS; modified vaccinia Ankara-Bavarian Nordic) at the Massachusetts General Hospital Sexual Health Clinic (SHC) between July 2022-July 2024. The SHC offers comprehensive sexual health services to adult patients including STI testing, treatment, and prevention regardless of insurance status in Boston, MA. Individuals were divided into two cohorts according to the visit type of their first mpox vaccine-related encounter: cohort 1 included patients receiving mpox vaccine only (vaccine-only visit); cohort 2 included patients vaccinated during regular (routine or urgent) clinic visits scheduled for another reason.

Demographic variables included age, gender identity, race, ethnicity, and zip code. Clinical variables included mpox vaccine data, HIV tests and results, and PrEP prescriptions. We determined socioeconomic status using 2022 social vulnerability index (SVI) data from the Centers for Disease Control and Prevention. The SVI score determines relative social vulnerability using U.S. Census tract data and provides a score between 0 and 1, with a higher score indicating greater vulnerability⁴. When a zip code spanned multiple census tracts, we calculated the weighted average SVI score using the ratio of total addresses within a tract over total addresses in the zip code⁵.

We compared demographics between the SHC vaccine population and all individuals vaccinated in MA using MA Department of Public Health mpox vaccine administration data, which concluded reporting on 9/1/2023². We subtracted the number of people vaccinated at the SHC before 9/1/2023 from the number recorded by the state per demographic category, as the SHC reported mpox vaccinations to MA, and compared this population to those vaccinated at the SHC before 9/1/2023.

The primary outcome was HIV testing or new PrEP prescription recorded within 90 days of first mpox vaccination encounter. We selected this window based on previous studies assessing PrEP uptake within 90 days following an intervention^6,7. Demographic analysis included all patients vaccinated at the SHC, but the linkage to HIV prevention analysis excluded those on HIV PrEP or living with HIV at the time of vaccination.

Statistical analysis

Categorical variables were summarized as proportions and compared using the chi-square test. Continuous variables were summarized as median with interquartile range (IQR) and compared using the Wilcoxon Rank-Sum test. Statistical significance was set at alpha<0.05. Statistical analyses were performed using STATA (version 18.0; StataCorp).

Patient consent statement

The study was approved by the Mass General Brigham Institutional Review Board. Individual patient consent was not required for this health records study.

Results

Demographic characteristics

3291 individuals received at least one mpox vaccine at the SHC between July 2022 and July 2024 (Table 1). The median age was 34 years (IQR 28, 45); 197 (6.7%) identified as Black; 436 (15.5%) reported Hispanic ethnicity; and 2985 (91.4%) identified as male gender. Slightly over half (1699, 51.7%) had an SVI score in the first quintile, corresponding to highest socioeconomic status.

Table 1:

Characteristics of individuals receiving mpox vaccination at a specialized sexual health clinic stratified by vaccine visit type.

	Total (n = 3291)	Vaccine-only visit (n = 2768)	Vaccine during regular clinic visit (n = 523)	p-value
n(%) or median [IQR]
New patient at clinic	2736 (83.1%)	2464 (89.0%)	272 (52.0%)	<0.0001
Age
	34 [28, 45]	34 [28, 47]	30 [25, 38]	<0.0001
Race, n=2951				<0.0001
White	2102 (71.2%)	1810 (72.6%)	292 (62.8%)
Asian	301 (10.2%)	241 (9.7%)	60 (12.9%)
Black	197 (6.7%)	164 (6.5%)	33 (7.1%)
Other	351 (11.9%)	279 (11.2%)	80 (17.2%)
Hispanic ethnicity, n=2821	436 (15.5%)	315 (13.4%)	121 (25.9%)	<0.0001
Gender Identity, n=3264				0.037
Cisgender Male	2,985 (91.4%)	2504 (91.3%)	481 (92.3%)
Cisgender Female	163 (5.0%)	147 (5.3%)	16 (3.1%)
Transgender/Nonbinary/Other	116 (3.6%)	92 (3.4%)	24 (4.6%)
Social Vulnerability Index in First Quintile*, n=3286	1699 (51.7%)	1464 (53.0%)	235 (45.1%)	0.001

2768 individuals were in the vaccine-only group (cohort 1), and 523 in the regular clinic visit group (cohort 2). In cohort 1, 2464 (89%) were new patients to the SHC, while 272 (52%) of cohort 2 were new patients (p<0.0001). Those in cohort 2 were younger than those in cohort 1 (median age 30y vs 34y; p<0.0001), more likely to identify as Hispanic (25.9% vs 13.4%; p<0.0001), and less likely to have an SVI score in the first quintile (45.1% vs 53.0%; p=0.001). There were significant differences in the racial (p<0.0001) and gender identity (p=0.037) composition between cohorts. A greater proportion of cohort 2 identified as Black (7.1% vs 6.5%), Asian (12.9% vs 9.7%), or another racial identity (17.2% vs 11.2%), and fewer as White (62.8% vs 72.6%)

The SHC vaccine population differed significantly from the total vaccinated population in Massachusetts (MA) in age (p<0.0001) and race-ethnicity (p<0.001) (Supplemental Table 1). Relative to MA, a greater proportion of the SHC population were age 20–39 (63.3% vs 54.5%) and identified as Asian, non-Hispanic (9.6% vs 6.4%) or Black or African American, non-Hispanic (6.0% vs 5.3%). Although individuals under 18 were vaccinated in MA, no minors were vaccinated at the SHC.

Finally, 153 (3.9%) individuals in the study population received only the second dose of the vaccine series at the SHC. Of the 3138 who received the first dose, 2046 (73.9%) in cohort 1 and 331 (63.3%) in cohort 2 returned for the second dose.

HIV prevention

Between both cohorts, 2818 people were not known to be on PrEP at the time of vaccination: 2540 (92%) in cohort 1, 278 (53%) in cohort 2 (Figure 1). 355 individuals received an HIV test either during the vaccine visit or within 90 days following: 107 (4.2%) in cohort 1, 248 (89%) in cohort 2. In cohort 2, 160 of the 248 (65%) received an HIV test during the first mpox vaccine encounter only, 12 (5%) received an HIV test only in the 90 days following the vaccine visit, and 76 (31%) received an HIV test during the vaccine encounter and within 90 days following. All HIV tests in cohort 1 occurred following the vaccine visit. There were no positive HIV tests during the study period. Overall, 223 people were prescribed PrEP either during the vaccine visit or within 90 days following: 34 (1.3%) in cohort 1, 189 (68%) in cohort 2. In cohort 2, 170 were prescribed PrEP during the vaccine visit, and 19 within 90 days following. In cohort 1, all new PrEP prescriptions were provided after the vaccine visit.

Figure 1:

Proportion of vaccine cohort that received PrEP or HIV testing concurrently with mpox vaccination or within 90 days of first vaccine-related encounter.

Discussion

In our analysis of mpox vaccination in a sexual health clinic, we observed that vaccine-only appointments were more often attended by new patients with higher socioeconomic status and who identify as White. A small number of vaccinated individuals returned within 90 days for HIV prevention services. A significant proportion of regular clinic visits included concurrent mpox vaccination and HIV prevention.

During the 2022 mpox outbreak, high-volume vaccination protocols provided mpox vaccines to a significant proportion of eligible individuals in MA. However, relatively few clinics in MA were equipped with vaccines. Our data suggest that individuals with higher socioeconomic status may have been more aware of and able to seek vaccination. In contrast, individuals vaccinated during regular clinic visits were more likely to identify with populations disproportionately represented among mpox cases, particularly Black and Hispanic groups². Targeted dissemination of information about vaccines and providing vaccine doses to clinics located in areas serving highly impacted populations may have been needed to reduce disparities in mpox vaccination and outcomes.

Vaccination encounters can further promote sexual health^8,9. Indeed, a large proportion of individuals vaccinated during regular clinic visits received concurrent HIV testing or PrEP and returned for these services within 90 days. While a greater proportion of cohort 1 returned for the second mpox dose, a smaller proportion received subsequent HIV prevention services. The decreased engagement in care seen in cohort 1 may be due to previously established sexual healthcare at other clinics not offering mpox vaccines. However, 52% of individuals with indications for PrEP in Massachusetts received a prescription in 2023, and the unmet need for PrEP among MSM is high, suggesting that the PrEP need in this cohort is likely greater than the 1.3% who received a prescription^10,11. Mpox vaccination can therefore serve as an entry into sexual healthcare for some individuals, and sexual health clinics are uniquely positioned to address these public health priorities if equipped with sufficient resources¹².

This study may be underestimating the true uptake of HIV prevention following vaccine-only appointments. Given the limited collection of HIV status and PrEP use information during vaccine-only appointments, individuals in cohort 1 may be engaged in this care externally. Screening for PrEP use and HIV/STI history, as well as providing information and referrals for sexual health services during vaccine-only encounters, could improve access to critical HIV prevention services in future vaccination efforts.

In conclusion, mpox vaccine-only visits were more likely attended by new patients with high socioeconomic status. A small number of vaccine visits resulted in an HIV test or PrEP prescription within 90 days. Future vaccination efforts can involve improving patient awareness of and access to vaccination and HIV and STI prevention.