Jury out on benefit of infant vaccine combo

It is unclear whether giving infants a combination vaccine for diphtheria-tetanus-pertussis, hepatitis B, and Haemophilus influenzae type B (DTP-HBV-HIB) protects them as effectively as separate DTP-HBV and HIB vaccines, a review of published studies indicates.

Based on the pooled results of 18 studies, “We could not conclude that the immune responses elicited by the combined vaccine were different from, or equivalent to, the separate vaccines,” the researchers wrote in The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research.

The World Health Organization recommends that routine infant vaccination programs use the combined DTP-HBV-HIB vaccine, yet the effectiveness and safety of adding the HIB vaccination to the DTP-HBV vaccine, compared with separate administrations, has yet to be systematically assessed, Dr. Edna Bar-On, of Rabin Medical Center in Petah-Tiqva, Israel and colleagues note in their report.

Combined vaccines, if they work well, have multiple advantages, the authors note, including fewer trips to the doctor, fewer painful shots, and perhaps increased compliance. There’s also a potential savings in supplies, syringes and office staff time.

Using data from 18 studies involving more than 10,000 children, Bar-On and her colleagues examined the use of the DTP-HBV-HIB vaccine and the separate DTP-HBV and HIB vaccine, administered to infants aged up to 2 years.

There was no difference between the combined vaccine and the separate vaccines regarding immune response, they report.

However, with the combined vaccine, there was some evidence of lower immune responses for HIB and HBV, and more minor side effects such as pain and redness at the injection site, although “these differences rely mostly on one study each,” the investigators caution.

“These results are therefore inconclusive,” they note.

Dr. Samir Shah, of Children’s Hospital of Pennsylvania, who was not involved in the study, told the Health Behavior News Service: “Since WHO has approved the regimen of a combination vaccine, it’s not unreasonable to use it if it facilitates administration and allows (doctors) to cover more people with the vaccine.”

“Ideally, what this study had hoped to address was whether the incidence of these diseases changes when using the combined vaccine. Unfortunately, none of the studies contained enough information to address that primary outcome,” Shah added.

SOURCE: The Cochrane Library, online July 8, 2009.