August 6, 2009

Combined Or Separate – Which Vaccine Is Best?

It is uncertain if giving infants a combined vaccine for diphtheria-tetanus-pertussis, hepatitis B, and Haemophilus influenzae type B helps them as much as individual DTP-HBV and HIB vaccines, a new study says.

After combing the 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 said in The Cochrane Library.

The World Health Organization advises that scheduled infant vaccination programs utilize the pooled DTP-HBV-HIB vaccine, but the efficiency and protection of adding the HIB vaccination to the DTP-HBV vaccine has not been reviewed, Dr. Edna Bar-On and colleagues wrote in their report.

Combined vaccines, if they are effective, have several advantages, like less trips to the doctor, fewer shots, and more compliance.

Using statistics from 18 studies involving 10,000 children, Bar-On and her colleagues reviewed the DTP-HBV-HIB vaccine and the separate DTP-HBV and HIB vaccine, given to infants 2 years and older.

There was not a difference in the combined vaccine and the individual vaccines in regards to immune response.

On the other hand, with the combined vaccine, there was some indication of lower immunity for HIB and HBV, and side effects like pain, even though "these differences rely mostly on one study each," the investigators warn.

"These results are therefore inconclusive," they wrote.

Dr. Samir Shah, of Children's Hospital of Pennsylvania, who was not part of the study, said to 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.


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