An Hasidic Jewish community has experienced recurrent hepatitis A
outbreaks since 1980. To
assess risk factors for illness during a 1985–6 outbreak, the authors
reviewed case records and
randomly selected 93 households for an interview and serologic survey. In
the outbreak, 117
cases of hepatitis A were identified, with the highest attack rate
(4·2%) among 3–5 year olds.
Among the survey households, the presence of 3–5 year olds was the only
risk factor that
increased a household's risk of hepatitis A (indeterminant relative
risk, P=0·02). Furthermore,
case households from the outbreak were more likely to have 3–5 year
olds than were control
households from the survey (odds ratio=16·4, P<0·001).
Children 3–5 years old were more
likely to have hepatitis A and may have been the most frequent transmitters
of hepatitis A in
this community. Hepatitis A vaccination of 3–5 year olds can protect
this age group and might prevent future outbreaks in this community.