New hepatitis recommendations issued

July 2006

This spring – perhaps lost among the announcement of new vaccines – was the Morbidity and Mortality Weekly Report (MMWR. 2006;55[RR07]:1-23) with expanded indications for the use of hepatitis A vaccine.

The last recommendations in 1999 called for the immunization of children 24 months of age in states with an incidence of hepatitis A infection at least twice the national rate with an option for immunization in other places with a somewhat increased risk.

In 2005, use of the vaccine in those as young as 12 months of age was approved. This and the realization that the incidence in the targeted states was equal to or lower than the other states led to new recommendations, ie, that all children should receive hepatitis A vaccine at 1 year of age. It also stated that the programs already in place for immunizing up to age 18 should not be stopped, but that the new recommendations should be phased in. Other communities may want to consider programs for immunizing those up to age 18. The ultimate goal is universal immunization against hepatitis A and elimination of the disease. The recommendations for high-risk groups, eg, travelers, those with chronic liver disease, etc., are reiterated.

Foreign travel

What is of particular interest is the number of cases in children who have traveled abroad. More than one-quarter of hepatitis cases in children can be attributed to foreign travel, mostly to Latin America. It is important to remember when families are traveling to countries where hepatitis A is endemic to include them among those who should receive prophylaxis. If it is more than four weeks before the start of travel, they should receive vaccine if they were not previously vaccinated. If not, they should receive vaccine and get immune globulin (IG), 0.02 mL/kg for travel less than three months and 0.06 mL/kgm for longer travel. If there is time for only a single dose of vaccine before onset of travel, a second dose should be given later. IG will interfere with the administration of live vaccines. This should be considered when immunizing children for foreign travel. The countries where prophylaxis is indicated can be found in this MMWR reference.

Children are frequently the source of cases in adult household members in whom the disease is likely to be much more serious. Seventy percent of cases in children younger than 7 are subclinical, yet they are quite capable of infecting others. Infection can be detected by testing for serum IgM. Prophylaxis with IG in day care centers is triggered in instances where cases in multiple families of attendees occur even in the absence of cases in the children themselves; those in diapers are more likely to spread infections as the virus is spread from feces. The greatest danger of transmission is in the two weeks prior to the onset of jaundice in those who become icteric. There are no special recommendations for immunization of day care attendees or personnel at this time.

Vaccines in children

There are two vaccines licensed for children in the United States, and they are interchangeable. The units differ for these two vaccines, Havrix (GlaxoSmithKline) and Vaqta (Merck). In addition, there are different preparations for those older and younger than 18 years of age.

“Vaqta for those aged 12 months to 18 years should receive 25 U per dose in a two-dose schedule; persons aged older than 18 years should receive 50 U per dose in a two-dose schedule. Havrix for those 12 months to 18 years, should receive 720 EL.U. per dose in a two-dose schedule; and for persons aged older than 18 years, 1,440 EL.U. per dose in a two-dose schedule,” according to the recommendations. Serologic screening of children is not recommended, as the yield of seropositives is not likely to be high enough to offset the cost of these rather expensive vaccines. It is not recommended for routine immunization of health care workers but hand washing between patients is.

Another document on hepatitis B in infants, children and adolescents (MMWR. 2005;Vol. 54:RR-16) recently has been issued by the Advisory Committee on Immunization Practices.

The salient points of this document are to ensure that infants are vaccinated at birth with single antigen hepatitis B vaccine — combination vaccine is not approved before 6 weeks of age — and that maternal hepatitis B surface antigen (HBsAg) testing or lack of it is employed in the management of newborns.

It is estimated that about half of women who are HBsAg-positive are not identified prenatally. Immunization at birth would substantially reduce the risk to these infants. The past suspension of newborn immunization due to the thimerosal-containing vaccines still is having an effect on administration of a birth dose.

The second issue is emphasis on the need to review the immunization records of children aged 11 and 12 years and children and adolescents below 19 years who were born in countries with intermediate or high levels of HBV endemicity. These countries are defined in the document. This is particularly important in light of the finding of a significant number of infected people in the New York area. It is important that these individuals be protected prior to their sexual debut.

Of particular concern are infants for whom the maternal record of testing is not available at the time of delivery. They should be given a birth dose of vaccine and maternal testing should be performed immediately. Infants of mothers who are found to be HbsAg-positive should receive hepatitis B IG as soon as possible and preferably before seven days post partum. Infants who are born to mothers known to be HbsAg-positive should receive vaccine and hepatitis B IG within 12 hours post partum. The infants should be tested for HbsAg and anti-HBs no sooner than 9 months of age. It is optimal to immunize infants who weigh greater than 2,000 gm. However, infants whose mothers are not known to be HbsAg-negative should receive vaccine and this dose should not counted in the number to complete the series.

There has been great progress in the control of both hepatitis A and B in the United States. The reduction in hepatocellular carcinoma in areas where hepatitis B has been endemic is a most impressive accomplishment. It also reminds those of us who care for the young and do not see the long-term consequences of failure to prevent maternal-infant transmission of its importance. Acquisition of infection at birth leads to chronic infection in about 90% of individuals and has a very high risk of progressing to cirrhosis or cancer.