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MEASURING HEPATITIS A

Tuesday, 6th of December 2011

• MEASURING HEPATITIS A

 

Background: World 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.

 

Results: Several 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.

 

Conclusion: For 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.

 

Also at http://www.bmj.com/content/343/bmj.d7157