Hepatitis B Shot Shields Newborns
It protects them if mom carries the virus, studies show
FRIDAY, Jan. 27, 2006 (HealthDay News) -- Immunizing the newborns of mothers with hepatitis B prevents the babies from becoming infected with the virus as well, a new study confirms.
The American Academy of Pediatrics already recommends that babies of mothers with hepatitis B be vaccinated within 12 hours of birth, and babies of mothers without the infection be vaccinated before they are 2 months old.
"It's a nice study, but the result just confirms what a lot of us already know," said Dr. Charles Mitchell, professor of pediatrics at the University of Miami's Miller School of Medicine.
The findings appear in the Jan. 28 issue of the British Medical Journal.
Experts estimate that approximately 350 million people worldwide carry the hepatitis B virus. The pathogen attacks the liver and can cause lifelong infection, scarring of the liver, liver cancer, liver failure and death.
Mother-to-child transmission accounts for 35 percent to 50 percent of all infections; the virus can also be spread through sex and intravenous drug use.
If a mother tests positive for both hepatitis B surface antigen and a second antigen called "e" antigen, she is more likely to pass the virus on. Mothers who are positive for only the surface antigen, however, have a considerably lower chance of infecting their offspring. Antigens are substances that stimulate an immune response. Different antigen characteristics usually predict different courses the disease can take.
Currently, two types of vaccines for hepatitis B are licensed, a plasma-derived vaccine and a recombinant (DNA-derived) vaccine. Both vaccines require repeated injections over several months to work effectively.
Hepatitis B immunoglobulin, on the other hand, works immediately and seems to stay effective for several months. Immunoglobulin contains antibodies that fight the virus.
For this new "meta-analysis," the authors looked at 29 randomized clinical trials of hepatitis B vaccines and immunoglobulin in newborn infants of mothers who tested positive for hepatitis B surface antigen.
"Hepatitis B vaccine, hepatitis B immunoglobulin, or the combination of vaccine plus immunoglobulin given to the newborn infants of mothers positive for hepatitis B surface antigen prevents the occurrence of hepatitis B," concluded study co-author Dr. Yan Gong, research assistant at Copenhagen University Hospital in Denmark.
The combination of vaccine and immunoglobulin was more effective than vaccine alone. There was no difference between the two types of vaccine, the study found.
The practice of using hepatitis B vaccine, even in combination with immunoglobulin, is not new, Mitchell said.
The exact mode of delivery is not always the same, however.
"Since the World Health Organization called for an immunization program for hepatitis B, many countries and areas follows it but in different ways regarding the regimen, dose, and schedule of both hepatitis B vaccines and immunoglobulin," Gong said.
Randomized trials to determine these specifics are still needed, Gong added.
For more on hepatitis B infection, head to the U.S. Centers for Disease Control and Prevention.