dermatophyte infections

Pertussis Vaccination at Birth?

LARISSA HIRSCH, MD and CHARLES A. POHL, MD—Series Editor
Dr Hirsch is an instructor of pediatrics at New York Presbyterian Hospital, Weill Cornell Medical Center in New York City. She is also a medical editor for KidsHealth.org. Dr Pohl is professor of pediatrics and associate dean of student affairs and career counseling at Jefferson Medical College in Philadelphia.

Trading one dangerous scenario for another?

Pertussis has long been known to cause severe disease and death in infants, especially in those who are unvaccinated or who are too young to be immunized. With the number of pertussis cases in the United States increasing,1 those of us who care for susceptible infants are looking for solutions to this dangerous problem.

Some physicians consider immunizing women before pregnancy or immediately postpartum to reduce the risk of infant exposure and to potentially provide passive immunity to the child. Others encourage booster shots for close contacts of young infants. With the booster shot now included in the recommended schedule of routine immunizations of teenagers and adults, it is hoped that the amount of pertussis present in the community will decrease.

In a study recently published in the Journal of Pediatrics, Knuf and colleagues2 took a different approach to the pertussis situation by examining the effects of a dose of acellular pertussis vaccine given shortly after birth. In this double-blind controlled study performed in Germany, 121 healthy infants were randomized to receive either a dose of acellular pertussis vaccination or hepatitis B vaccination between days 2 and 5 of life. Both groups were then given DTaP-HBV-IPV/Hib at ages 2, 4, and 6 months. All vaccines given were manufactured by GlaxoSmithKline, which supported the study.

The researchers measured antibody concentrations in patients before the first vaccine dose, and then again at ages 3, 5, and 7 months. They also had parents record any signs and symptoms for 8 days after each vaccine to look for adverse reactions. Signs and symptoms were then graded for severity by the investigators.

Among infants given a birth dose of acellular pertussis vaccine, there was no decrease in immune responsiveness to pertussis after the primary vaccine course. In fact, there was an accelerated response that persisted against all 3 pertussis antigens until 5 months, and for 1 pertussis antigen until at least 7 months. When compared with infants given a birth dose of hepatitis B vaccine, however, those who received acellular pertussis had a decreased antibody response to hepatitis B virus. It is unclear whether this decrease was the result of having received 1 fewer hepatitis B vaccine dose or to a reduced response to the antigens presented. Among the acellular pertussis group, there was also a decrease in responsiveness to Haemophilus influenzae.

After the birth dose, no significant statistical difference in adverse reactions was seen between the acellular pertussis group and the hepatitis B group. Fever did not develop in infants in either group, although some in each group were irritable, drowsy, and had localized erythema. After the remaining 3 vaccine doses, there were similar rates and severity of adverse events between the 2 groups.

The Knuf study has many limitations—including the small study size, withdrawal of patients, and lack of a control group that did not receive any vaccines at birth. However, it does address an interesting method of reducing pertussis-related morbidity and mortality in infants.

By providing vulnerable newborns with an antibody response to a dangerous bacterium, we could potentially reduce the impact of this disease. The birth dose of acellular pertussis was well tolerated . . . but if it decreases immunity to H influenzae, are we only trading one dangerous scenario for another?

Until further studies are done, we will have to continue to encourage booster shots among adolescents and adults—especially in women of childbearing age and close contacts of babies—to protect young infants from pertussis.