Immunity to hepatitis A when outbreaks of infection in men who have sex with men (MSM) are rare

Background

Epidemics of hepatitis A among men who have sex with men (MSM) have decreased significantly in recent years although the level of immunity that is required to prevent epidemics has not been studied. Our aim was to determine the level of immunity to hepatitis A among MSM.

Methods

This was a retrospective study conducted using notifications of Hepatitis A in Victoria from 1991 to 2010, serological testing for hepatitis A among MSM attending Melbourne Sexual Health Centre (MSHC), and vaccination records among MSM attending MSHC.

Results

Hepatitis A notifications declined from 370 to 47 and the male to female ratio declined from 4.2 to 0.9 in Victoria between1991 to 2010. Between 2002 and 2011, there were 12,064 individuals MSM seen at MSHC of whom 3055 (25%) were tested for hepatitis A antibodies and 1180 (39%) had antibodies. The proportion of MSM who were tested for hepatitis A rose significantly over time (P < 0.01), but the proportion of these with hepatitis A antibodies did not (P = 0.28). Hepatitis A antibodies were more common in MSM over 30 (54%) compared to those 30 or less (32%), (Crude Odds Ratio 2.5 (95% confidence interval 2.1–2.9)) and were uncommon in MSM under 20 (19%). Vaccination against hepatitis A was recorded in 49% of 660 clinical files of MSM who attended the centre between 2003 and 2011 and did not change over time (P = 0.42) but was significantly more common in those over 30 years of age (P < 0.005).

Conclusion

Hepatitis A is rare in MSM in Victoria where levels of immunity are about 40–50%. As outbreaks have occurred when levels of immunity were around 30%, maintaining vaccination levels over 40–50% is important if outbreaks are to be prevented. The lower levels of immunity in younger MSM create the potential for outbreaks in this sub-group.     

Effect of age and frequency of injections on immune response to hepatitis B vaccination in drug users

Despite the high immunogenicity of the hepatitis B vaccine, evidence suggests that immunological response in drug users is impaired compared to the general population.A sample of not-in-treatment adult drug users from two communities in Houston, TX, USA, susceptible to hepatitis B virus (HBV), was sampled via outreach workers and referral methodology. Participants were randomized to either the standard multi-dose hepatitis B vaccine schedule (0, 1, and 6 months) or to an accelerated (0, 1, and 2 months) schedule. The participants were followed for 1 year. Antibody levels were measured at 2, 6 and 12 months after enrollment in order to determine the immune responses.At 12 months, cumulative adequate protective response was achieved in 65% of the HBV susceptible subgroup using both the standard and accelerated schedules. The standard group had a higher mean antibody titer (184.6 mIU/mL vs 57.6 mIU/mL). But at 6 months, seroconversion at the adequate protective response was reached by a higher proportion of participants and the mean antibody titer was also higher in the accelerated schedule group (104.8 mIU/mL vs. 64.3 mIU/mL). Multivariate analyses indicated a 63% increased risk of non-response for participants 40 years or older (p = 0.046). Injecting drugs more than once a day was also highly associated with the risk of non-response (p = 0.016).Conclusions from this research will guide the development of future vaccination programs that anticipate other prevalent chronic conditions, susceptibilities, and risk-taking behaviors of hard-to-reach populations.     

Barriers to uptake of hepatitis C virus (HCV) health intervention among men who have sex with men in Southwest China: A qualitative study

Men who have sex with men (MSM) are at risk of contracting the hepatitis C virus (HCV). Previous studies have documented low uptake of sexually transmitted disease (STD) prevention and health services among Chinese MSM. We carried out qualitative research among MSM in Southwest China. By taking the Health Brief Model (HBM) as a framework, we aimed to determine the underlying factors related to use of HCV health intervention services among MSM. From May to July 2018, we conducted in-depth interviews in Southwest China with 20 participants. Our research revealed that a lack of knowledge about HCV prevention was the main reason why MSM failed to perceive their susceptibility to HCV and had low motivation to seek preventive services. Poor service accessibility and unpleasant experiences seeing doctors also exerted negative influences on health care-seeking behaviour in MSM. More trust and understanding needs to be built between health providers and MSM. Protection of privacy for MSM should be guaranteed in the delivery of health interventions. In addition, the interviewees showed refusal to engage with health interventions being specifically targeted at MSM, which would create a sense of being ‘labelled’. Tailored health interventions may overemphasise their sexuality, segregate them from heterosexuals, and make them feel alienated. Therefore, we speculate that differential treatment may be an obstacle for MSM to become involved in health interventions.     

The impact of the COVID-19 pandemic on hepatitis B virus vaccination and transmission among men who have sex with men: A mathematical modelling study

BackgroundDuring the COVID-19 pandemic, the number of hepatitis B virus (HBV) vaccinations among men who have sex with men (MSM) has been considerably lower than before the pandemic. Moreover, less frequent HBV testing and a reduction in numbers of sex partners have been reported. We assessed the impact of these COVID-19-related changes on HBV transmission among MSM in the Netherlands.MethodsWe estimated the changes in sexual activity, HBV testing, and HBV vaccination among MSM during the pandemic from Dutch data. We used a deterministic compartmental model and investigated scenarios with small or large declines in sexual activity, testing, and vaccination for the current phase of the pandemic (without available data). We examined the increase in HBV vaccinations needed to prevent further increase in HBV incidence.ResultsWith a decrease in numbers of sex partners of 15–25% during the first lockdown and 5% during the second lockdown, we found a decline of 6.6% in HBV incidence in 2020, despite a >70% reduction in HBV testing and vaccination during the first lockdown. With numbers of sex partners rebounding close to pre-pandemic level in 2021, and a reduction of 15% in testing and 30% in vaccination in 2021, we found an increase of 1.4% in incidence in 2021 and 3.1% in 2026. With these changes, an increase of ≥60% in HBV vaccinations in 2022 would be needed to bring the HBV incidence in 2023 back to the level that it would have had if the COVID-19-related changes had not occurred.ConclusionsDespite reductions in sexual activity during the COVID-19 pandemic, the decrease in HBV vaccinations may result in a small increase in HBV incidence after 2021, which may persist for years. It is important to restore the vaccination level and limit further increase in HBV transmission among MSM.     

Targeted outreach hepatitis B vaccination program in high-risk adults: The fundamental challenge of the last mile

BackgroundThe aim of this study was to evaluate the cost-effectiveness of the on-going decentralised targeted hepatitis B vaccination program for behavioural high-risk groups operated by regional public health services in the Netherlands since 1-November-2002. Target groups for free vaccination are men having sex with men (MSM), commercial sex workers (CSW) and hard drug users (HDU). Heterosexuals with a high partner change rate (HRP) were included until 1-November-2007.MethodsBased on participant, vaccination and serology data collected up to 31-December-2012, the number of participants and program costs were estimated. Observed anti-HBc prevalence was used to estimate the probability of susceptible individuals per risk-group to become infected with hepatitis B virus (HBV) in their remaining life. We distinguished two time-periods: 2002–2006 and 2007–2012, representing different recruitment strategies and target groups. Correcting for observed vaccination compliance, the number of future HBV-infections avoided was estimated per risk-group. By combining these numbers with estimates of life-years lost, quality-of-life losses and healthcare costs of HBV-infections - as obtained from a Markov model-, the benefit of the program was estimated for each risk-group separately.ResultsThe overall incremental cost-effectiveness ratio of the program was €30,400/QALY gained, with effects and costs discounted at 1.5% and 4%, respectively. The program was more cost-effective in the first period (€24,200/QALY) than in the second period (€42,400/QALY). In particular, the cost-effectiveness for MSM decreased from €20,700/QALY to €47,700/QALY.Discussion and conclusionThis decentralised targeted HBV-vaccination program is a cost-effective intervention in certain unvaccinated high-risk adults. Saturation within the risk-groups, participation of individuals with less risky behaviour, and increased recruitment investments in the second period made the program less cost-effective over time. The project should therefore discus how to reduce costs per risk-group, increase effects or when to integrate the vaccination in regular healthcare.