A new pediatric dose and vaccination schedule for Havrix has been approved as treatment for hepatitis A. The additional licensure from the Food and Drug Administration will enable vaccination of children and adolescents, two through 18 years of age, on the same schedule as is already available for adults.
The new schedule for children and adolescents will require one less injection with Havrix than the initially licensed schedule, and thus one less trip to the doctor's office. The new schedule starts with a primary dose of 720 EL.U./0.5 ml, which affords protection for up to one year. A booster dose, also 720 EL.U./0.5 ml, administered six to 12 months after the primary dose, is recommended to extend protection. Previously, children and adolescents required two primary doses of 360 EL.U./0.5 ml each, at a one-month interval, followed by a booster dose of 360 EL.U./0.5 ml, six to 12 months after the first primary dose (this regimen will continue to be available for those who have already started with the primary injection).
Children and adolescents who have been started on the 360 EL.U./0.5ml dose of Havrix should complete the three-dose schedule at that dose. Those who have not yet received any doses of Havrix can begin vaccination with the 720 EL.U./0.5 ml dose on the two-dose schedule.
Havrix, initially licensed in the United States in February 1995, demonstrated high efficacy in clinical trials. Vaccination induced production of antibodies in up to 98% of adults and in up to 96% of children and adolescents within 15 days of the primary injection.
The most common adverse events in clinical trials were injection site soreness (56% of adults and 21% of children) and headache (14% of adults and 9% of children). As with all vaccines, expanded commercial use could reveal rare adverse events not observed in clinical trials.
Hepatitis A is a highly contagious disease spread by the fecal-oral route through close person-to-person contact or ingestion of contaminated food or water. Among people two through 18 years old, symptoms tend to vary with age, ranging from generally flu-like symptoms in young children to debilitating, adult-like symptoms and possibly acute liver injury in adolescents. The more serious symptoms include jaundice, fever, vomiting, diarrhea, rash, and joint pain. On average, adults with hepatitis A miss 30 days of work or routine daily activity.
Additionally, because children may not have symptoms recognizable as hepatitis A, infection of children may serve to initiate or perpetuate community-wide outbreaks. Several such outbreaks are ongoing in the United States.
In the United States, there are an estimated 143,000 cases of hepatitis A each year.
Children and adolescents at risk of hepatitis A include those residing in communities experiencing outbreaks, belonging to populations that experience cyclic hepatitis A epidemics, such as native people of Alaska and the Americas, or traveling to areas where the disease is endemic.