The majority of US adults at risk of hepatitis B remain unvaccinated against the potentially life-threatening infection of hepatitis, according to research published in advance of print in the online edition of Infection.
The research highlighted missed opportunities for vaccination, especially for individuals who had received health care while in prison. The authors express concern that hepatitis vaccination programmes targeted at adults are seriously underfunded.
“In 2005, a total of only 4.5% of the $234,897,000 funds appropriated for the purchase of vaccines was used for adult populations, yielding a funding shortfall of approximately $160 million. This translates into a substantial proportion of uninsured adults being unable to access recommended immunization services through federally funded vaccination programs.”
Separate research conducted in Barcelona and published in BMC Infectious Diseases showed that hepatitis A vaccination efforts were not preventing periodic outbreaks of the infection among gay men.
A highly effective vaccine against hepatitis B has been available since the early 1980s. Nevertheless, incidence of the infection in the US remains high, with approximately 80,000 new diagnoses each year.
Approximately 75% of newly reported hepatitis B infections are in specific high-risk groups. These include injecting drug users, gay and other men who have sex with men, people with a history of sexually transmitted infections or high numbers of sex partners, and healthcare workers. With the exception of the latter, vaccination rates in these high-risk groups are low.
US investigators used results from the 2007 Behavioral Risk Factor Surveillance Survey (BRFSS) to assess rates of hepatitis B vaccination in high-risk groups and to see if opportunities for vaccination had been missed.
The BRFSS is a telephone survey which includes a representative sample of the US population. A total of 15,432 high-risk individuals were included in the present analysis.
Over half (56%) reported that they had not been vaccinated against hepatitis B.
Higher rates of vaccination were seen in those aged under 33 years than in individuals aged over 33 (61 vs 33%). A smaller proportion of individuals who were in a relationship were vaccinated compared to those who reported not being in a relationship (44 vs 51%).
Use of healthcare was also associated with the likelihood of hepatitis B vaccination. Higher rates were seen in individuals who had been vaccinated against influenza and pneumonia than in patients who had not been immunised against these infections (57 and 61% vs 45 and 44%).
Rates of vaccination were also related to healthcare provider. Two-thirds of individuals who reported being tested for HIV by a private doctor had been vaccinated against hepatitis B, as had 60% of individuals who were tested for HIV at a hospital, 51% tested at a clinic, and 50% at a counselling and testing site.
In contrast, 71% of individuals who had had an HIV test in prison remained unvaccinated against hepatitis B, as did 66% of individuals screened for HIV at a drug treatment facility.
Multivariate analysis confirmed the association between the receipt of immunisations against pneumonia (OR = 2.27; 95% CI, 1.80-2.87) and influenza (OR = 1.68; 95% CI, 1.39-2.03) and an increased likelihood of hepatitis B vaccination.
“One could posit that patient who reported receiving the influenza and/or pneumonia vaccine have a heightened awareness of the utility and importance of vaccines in disease prevention and therefore were more likely to accept or request a vaccine against hepatitis B,” suggest the authors.
Patients who reported being unable to see a doctor because of concerns about cost were 33% less likely to be vaccinated against hepatitis B (OR = 0.77; 95% CI, 0.60-0.98).
“High costs associated with this vaccine may discourage uptake in this population,” write the investigators.
HIV testing location was also confirmed as a predictor of vaccination. Individuals tested in the correctional facility had their chances of being vaccinated reduced by 40%.
“Missed opportunities for hepatitis B vaccination continue to occur in vaccine delivery settings frequented by high-risk adults, such as prisons and jails and drug treatment centres,” note the reseachers
They conclude, “the results of this study…underscore the inadequacy of vaccination coverage in high-risk individuals and highlight areas of opportunity to bridge gaps in vaccination coverage.”
A separate study showed that current vaccination efforts are failing to prevent outbreaks of hepatitis A in gay men in Barcelona.
Gay and other men who have sex with men are a known risk group for hepatitis A.
A vaccine that provides a high level of protection against hepatitis A is available. Since 1994 health authorities in Barcelona have recommended that all gay men should receive this immunisation. Starting in 1998, a combined hepatitis A and hepatitis B vaccine has been provided to all twelve year-olds in the city. In 2004 an outreach programme was launched offering the vaccine and other sexual health services at gay saunas in the city.
Investigators wished to see if vaccination efforts were having an impact of on incidence of hepatitis A in Barcelona generally and in gay men specifically.
Incidence of the infection between 1989 and 2010 was analysed.
This showed that the median annual incidence of hepatitis A was 4.7 per 100,000 females and 11.7 per 100,000 males. Over the period of the study, incidence of hepatitis A fell significantly in females (p = 0.002) but remained steady in men.
Three large outbreaks of hepatitis A were identified in gay men. These occurred between January and December 2002, from mid 2003 to mid 2004, and from September 2008 to June 2009.
The mean age of individuals diagnosed with the infection was between 31 and 33 years. A significant and unchanging proportion of men were HIV-positive (21 to 28%).
In 2002 outbreak, 44% of cases were in men who reported using saunas. This had fallen to 19% in the 2008-2009 outbreak (p = 0.0001). The investigators believe this shows that their vaccination outreach programme in saunas was successful.
The proportion of cases involving sex workers also fell from 7 to 0%.
Almost a fifth of patients reported recent travel to another industrialised country in the six weeks before their diagnosis with hepatitis A. Circulating genotypes of the infection were similar to those seen in London and other European cities.
“MSM present consistently high incidence without appearing to decrease,” conclude the investigators. “Prevention interventions which effectively reach the whole MSM community are needed.”
Ladak F et al. Hepatitis B in the United States: ongoing missed opportunities for hepatitis B vaccination, evidence from the Behavioral Risk Factor Surveillance Survey, 2007. Infection, online edition. DOI: 10.1007/s15010-011-0241-2, 2012 (click here for a pdf of the article).
Tortajada C et al. Hepatitis A among men who have sex with men in Barcelona, 1989-2010: insufficient control and need for new approaches. BMC Infectious Diseases, 21:11, 2012 (click here for the open access article).