Recent outbreaks of hepatitis A virus (HAV) infection among men who have sex with men (MSM) have occurred globally, nationally, and in New York City (NYC). An estimated critical immunity threshold against HAV is ≥ 70% to prevent outbreaks in MSM populations. National HIV Pre-exposure prophylaxis (PrEP) and post exposure prophylaxis (PEP) guidelines do not recommend HAV serology testing (ST) among MSM for PrEP/PEP initiation. At NYC sexual health clinics (SHC), all patients initiating PrEP or PEP receive HAVST. This analysis aims to determine the prevalence of HAV immunity among MSM initiating PrEP/PEP at SHC and determine subsequent HAV vaccine uptake.
Electronic medical record (EMR) data was extracted for HIV-negative MSM PrEP/PrEP patients who had HAVST for the first time at SHC from September 2016 to March 2019, with a follow up through July 2019. We examined demographics, immunization history and EMR administered vaccines. Patients reactive for HAV IgG were considered immune. Patients were considered vaccinated against HAV if they received at least one dose of HAV vaccine (Havrix™) or two doses of hepatitis A/B combination vaccine (Twinrix™) at SHC (or self-reported vaccination at other clinics).
Overall, 4233 MSM initiated PrEP/PEP and had HAVST. Median age was 28 years (IQR 25-33); 32% were Hispanic, 31% were non-Hispanic (NH) white, and 21% were NH Black. Foreign-born were 37% (n=1574). At time of PrEP/PEP initiation, 26% were diagnosed with bacterial STI’s. Sixty five percent were HAV immune (n=2733). Of 1500 patients not immune, 50% (n=743) received ≥1 dose of Havrix™ (n= 453) or Twinrix™ (n=290) within a year after HAVST. A total of 2437 (58%) patients self-reported receiving hepatitis A vaccination at non-NYC SHC settings; 37% (n=897) were not immune.
HAV immunity among this NYC MSM cohort was below the critical immunity threshold against HAV. Subsequent vaccination of this cohort likely increased their immunity to ≥ 70%. HAVST identified a significant number of HAV non-immune patients, despite self-reported hepatitis A vaccination. HAVST for MSM initiating PrEP/PEP and subsequent hepatitis A vaccination of non-immune patients is an effective intervention to prevent future HAV outbreaks.