The Hepatitis B Vaccine for Newborns

Q. If hepatitis B is a sexually transmitted disease, then why do newborns need to get the hepatitis B vaccine? Couldn't they wait until they were older? Connie, Texas

A. Hepatitis B is a viral infection that can lead to chronic liver infections and can lead to cirrhosis and hepatocellular carcinoma. In addition to blood, hepatitis B is transmitted by other body fluids, so it is technically a sexually transmitted disease. However, newborns are at big risk for getting hepatitis B from their mother who is already infected with the hepatitis B virus.

Although simply vaccinating those infants of mothers who are infected with hepatitis B and delaying the vaccine for other infants is one strategy for preventing hepatitis B in newborns, it is not as effective as universal immunization. In a universal immunization program, all newborn and infants are immunized with hepatitis B, even if their mother is negative for a hepatitis B infection.

The Birth Dose of Hepatitis B Vaccine

Giving this birth dose of hepatitis B vaccine helps prevent missing babies who have a mother that has an unknown hepatitis B infection, either because testing wasn't done or there is a testing mistake. It also avoids the situation in which the mother has a known hepatitis B infection, but the baby misses her hepatitis B shot anyway.

Another good reason to give all newborns the hepatitis B infection is that although most cases are known to be caused by exposure to blood and body fluids from somebody else with a hepatitis B infection, about 30% to 40% of infections are in people without any risk factors for infection.

According to the CDC, giving a birth dose of hepatitis B vaccine is a good idea because:

• it provides 'a "safety net" to prevent perinatal infection among infants born to HBsAg-positive mothers who are not identified because of errors in maternal HBsAg testing or failures in reporting of test results'
• the birth dose 'provides early protection to infants at risk for infection after the perinatal period'
• infants who get the birth dose of hepatitis B vaccine have 'higher rates of on-time completion of the hepatitis B vaccine series'
• it reduces the risk that a child could get hepatitis B later in childhood, even if he isn't at risk now from a mother with hepatitis B, since they could be exposed to another caregiver or family member with hepatitis B

Most importantly, although young children often have no symptoms when they develop a hepatitis B infection, they are very likely to go on to develop problems with chronic hepatitis. In fact, 90% of children who develop hepatitis before they are 12 months old will go on to develop chronic hepatitis B, for which there is no cure and few reliable treatments.

Targeting High Risk Groups

The alternative to universal immunization and giving the hepatitis B vaccine to all newborns would be to simply target high risk newborns and other people who are at high risk for getting hepatitis B infections. Unfortunately, health experts tried that when the hepatitis B vaccine first came out and it didn't work.

It wasn't until after the universal immunization program for the hepatitis B vaccine began that the rate of new hepatitis B infections in children began to drop.

_Sources:

Long: Principles and Practice of Pediatric Infectious Diseases, 2nd ed.

Gershon: Krugman's Infectious Diseases of Children, 11th ed.

MMWR. December 23, 2005 / Vol. 54 / No. RR-16. A Comprehensive Immunization Strategy to Eliminate Transmission of Hepatitis B Virus Infection in the United States.

Kliegman: Nelson Textbook of Pediatrics, 18th ed.

Hepatitis B. Weisberg SS - Dis Mon - September 2007; 53(9); 453-458.