Hepatitis A vaccine administered to persons after exposure to the hepatitis A virus has not been compared directly with immune globulin.
Immune globulin is known to be highly effective in preventing Hepatitis A when given within 2 weeks after exposure to the virus.
|Symptomatic infection with Hep A occurred in 4% receiving vaccine|
|New England Journal of Medicine|
Dr John Victor and colleagues from Michigan randomly assigned household and day-care contacts, 2 to 40 years of age, in Kazakhstan.
The participants received 1 standard age-appropriate dose of Hepatitis A vaccine or immune globulin within 14 days after exposure to patients with Hepatitis A.
Symptomatic Hepatitis A infection occurring between 15 and 56 days after exposure were then assessed during active follow-up of all susceptible contacts.
The researchers found of 4,524 contacts who underwent randomization, 1,414 were susceptible to Hepatitis A virus, and 1090 were eligible for the per-protocol analysis.
Among these contacts, 568 received Hepatitis A vaccine, and 522 received immune globulin.
The research team found that most contacts were children, and most received prophylaxis during the second week after exposure.
The baseline characteristics of the contacts were similar in the 2 groups.
The researchers confirmed symptomatic infection with Hepatitis A virus in 4% receiving vaccine, and 3% receiving immune globulin.
Dr Victor's team concluded, "Low rates of Hepatitis A in both groups indicate that Hepatitis A vaccine and immune globulin provided good protection after exposure."
"Although the study's prespecified criterion for noninferiority was met, the slightly higher rates of Hepatitis A among vaccine recipients may indicate a true modest difference in efficacy and might be clinically meaningful in some settings."
"Vaccine has other advantages, including long-term protection, and it may be a reasonable alternative to immune globulin for postexposure prophylaxis in many situations."