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An epidemic of hepatitis A in an institution for young children
Insights
A hepatitis A outbreak in an Athenian institution saw a high attack rate despite immunoglobulin (IG) use. Diagnostic tests like anti-HAV IgM and IgG were crucial for identifying infections, highlighting the need for comprehensive testing during epidemics.
Area of Science:
- Epidemiology
- Virology
- Public Health
Background:
- A common-source hepatitis A outbreak occurred in an Athenian institution housing 38 children.
- The majority of children lacked prior immunity to hepatitis A virus (HAV).
Purpose of the Study:
- To investigate the epidemiology and clinical characteristics of a hepatitis A outbreak in a children's institution.
- To evaluate the effectiveness of immunoglobulin (IG) administration and diagnostic assays during the epidemic.
Main Methods:
- Clinical examinations and serial blood draws from 38 children over three months.
- Serological testing for anti-HAV IgM and anti-HAV IgG antibodies.
- Detection of hepatitis A virus antigen and RNA in fecal specimens.
Main Results:
- The attack rate for hepatitis A was 62.2%, with a high ratio of icteric to anicteric cases (1:1.3).
- Immunoglobulin administration did not prevent clinical cases in the late incubation period but may have altered clinical expression.
- Anti-HAV IgM and IgG assays identified 82.6% and 95.7% of infections, respectively; one case was detected solely by viral antigen/RNA detection.
Conclusions:
- Comprehensive diagnostic testing, including serology and viral detection, is essential for accurate hepatitis A epidemic assessment.
- Early immunoglobulin administration may reduce clinical severity but can complicate diagnosis.
- Understanding outbreak dynamics and diagnostic limitations is critical for public health interventions.
Abstract:
A common-source epidemic of hepatitis A occurred in an Athenian institution boarding 38 children (mean age 4.8 years). All children were examined, and blood was drawn from each at the onset of the study and repeatedly during the next three months. Only one child (2.6%) was initially immune to hepatitis A virus as a result of prior infection. The attack rate (62.2%) and the ratio of icteric to anicteric cases (1:1.3) were high despite the administration of immunoglobulin (IG). Assays for anti-HAV IgM and a rising titer of anti-HAV IgG identified 19 (82.6%) and 22 (95.7%) of the 23 hepatitis A infections, respectively. One case (4.3%) was detected only by the presence of hepatitis A virus antigen and hepatitis A virus RNA in a fecal specimen, but these assays were otherwise marginally useful in this study. Nevertheless, the use of all available tests for the detection of hepatitis A virus is mandatory for the most accurate estimation of an epidemic of hepatitis A. Prompt administration of immunoglobulin had no effect on the number of clinical cases that were in the late incubation period, but it may have diminished the clinical expression of the infection and thus made diagnosis of infection more difficult.