Challenges to mapping the health risk of hepatitis A virus infection

Abstract

BackgroundWorld maps are among the most effective ways to convey public health messages such as recommended vaccinations, but creating a useful and valid map requires careful deliberation. The changing epidemiology of hepatitis A virus (HAV) in many world regions heightens the need for up-to-date risk maps. HAV infection is usually asymptomatic in children, so low-income areas with high incidence rates usually have a low burden of disease. In higher-income areas, many adults remain susceptible to the virus and, if infected, often experience severe disease.ResultsSeveral challenges associated with presenting hepatitis A risk using maps were identified, including the need to decide whether prior infection or continued susceptibility more aptly indicates risk, whether to display incidence or prevalence, how to distinguish between different levels of risk, how to display changes in risk over time, how to present complex information to target audiences, and how to handle missing or obsolete data.ConclusionFor future maps to be comparable across place and time, we propose the use of the age at midpoint of population susceptibility as a standard indicator for the level of hepatitis A endemicity within a world region. We also call for the creation of an accessible active database for population-based age-specific HAV seroprevalence and incidence studies. Health risk maps for other conditions with rapidly changing epidemiology would benefit from similar strategies.

Hepatitis A virus in West Africa: Is an epidemiological transition beginning?

“…However, if lower incidence rates are maintained for the next decade or longer, a growing proportion of adolescents and young adults — especially those who live in relatively high income, urban areas — may remain susceptible to HAV. At that time, public health officials in West-African countries may wish to consider whether targeted hepatitis A vaccination would be beneficial to some populations within their countries 6. In the meanwhile, clinicians practicing medicine in West Africa should be aware of the growing possibility of acute hepatitis A among older children, adolescents and young adults.…”

Estimation of Hepatitis A Virus Infection Prevalence Among Eastern Mediterranean and Middle Eastern Countries: A Systematic Review and Pooled Analysis

“…We know that HAV is more sever in adults. Considering this issue, future research should focus on the change in epidemiological patterns of HAV and investigate it as an emerging threat (33). According to this study, Middle East and EMR region currently might be considered as an intermediate-endemic area for HAV infection.…”

Progress Toward Eliminating Hepatitis A Disease in the United States

“…These NHANES estimates suggest that a large proportion of the U.S. adult population is susceptible to acute HAV at ages when the risk for illness and death is greatest. HAV remains endemic in much of the world (9,12,13,57). International travel and the global food economy create conditions that could contribute to HAV infection among an increasingly susceptible U.S. adult population.…”

“…Some investigators suggest that a substantial proportion of cases without recognized exposure are related to contaminated food (55,56). Herd protection provides a barrier against spread of HAV in populations but will not protect susceptible persons when exposed (43,57).…”