Poor increase on HAV vaccination coverage among people living with HIV after an immunization-based intervention

OBJECTIVES

To assess HAV serologic and vaccination status among people who live with HIV (PLWH), and to evaluate the impact of a vaccination-based strategy on HAV-negative patients in Seville, Spain.

METHODS

Study with two time-overlapping phases: (i) cross-sectional study of HAV immunity prevalence among PLWH followed at a Spanish hospital between August 2019 and March 2020. (ii) Patients seronegative for HAV, reliably unvaccinated were included in a before-and-after quasi-experimental study, with an intervention focused on HAV vaccination according to national recommendations in force.

RESULTS

Six hundred and fifty-six patients were included, of which 111 [17%, 95% confidence interval (95% CI) 14-20%] were seronegative for HAV. Of these, 48 [43% (95% CI, 34-53%)] individuals were MSM. The absence of HAV immunity was attributed in 69 [62% (95% CI, 52-71%)] patients to non-referral to vaccination, followed by lack of achievement of a correct vaccination scheme [n=26; 23% (95% CI, 16-32%)]. After the program implementation, 96 [15% (95% CI, 12-18%)] individuals were seronegative (17% vs. 15%, p=0.256), of whom 42 [41% (95% CI, 32-51%)] were MSM. The absence of immunity after the intervention was mainly attributed to: adherence failure in 23 [24.0% (95% CI, 15.8-33.7%)] patients, on-course immunization scheme in 34 [33% (95% CI, 24-43%)] individuals and pending appointment at the vaccine delivery unit in 20 [20.8% (95% CI, 13.2-30.3%)] patients.

CONCLUSIONS

A sizeable proportion of PLWH remains susceptible for HAV infection in future outbreaks. A program based on referral to the vaccine delivery unit yields poor results, largely due to program adherence failures. New strategies are needed to increase HAV vaccination coverage.