Public Health

Hepatitis A: close contacts at risk, despite immune globulin

Last Updated: 2004-09-15 12:10:38 -0400 (Reuters Health)

NEW YORK (Reuters Health) - The results of a study conducted in the Netherlands demonstrate that immune globulin does not always protect household contacts from hepatitis A virus (HAV) infection.

"However, it attenuates symptoms and effectively reduces further HAV transmission," Dr. Gerard J. B. Sonder from the Municipal Health Services in Amsterdam and colleagues report in the September issue of the American Journal of Public Health.

They designed the study to evaluate the current policy for prevention of secondary transmission of HAV, the hallmarks of which are hygienic precautions and passive immunization with immune globulin for susceptible household contacts.

They analyzed serological outcomes of 1242 household contacts of 569 patients with confirmed HAV infection. They discovered that more than half of the household contacts (n = 672) demonstrated HAV immunity.

Among the 570 nonimmune contacts, 161 (28.2%) were IgM positive at their first blood test and were considered to have coprimary infections and 86 (53%) were symptomatic.

The remaining 409 "susceptible" contacts received immune globulin and 186 (45%) returned for a second blood test 6 weeks later. At that time, 64 of 186 (34%) were infected with HAV, but only 12 (19%) had symptomatic infection.

"We found a high secondary seroconversion rate (34%) among susceptible contacts" despite timely immune globulin treatment, the authors note.

In this study, the interval between disease onset in the index patient and administration of immune globulin in the contact was not associated with the seroconversion rate in contacts or the likelihood of developing symptomatic HAV infection.

In Amsterdam, HAV infection is seen largely in two groups of people: travelers to HAV-endemic areas and homosexual men. Current guidelines in the Netherlands recommend HAV vaccination for both groups.

Am J Public Health 2004;94:1620-1626.