Study shows HPV vaccine can be delayed with minimal loss of effectiveness

A recent study conducted by Kathleen M. Neuzil has found that delaying doses of the vaccine against human papilloma virus until months later than recommended does not make the vaccine less safe or effective.

Neuzil, the clinical associate professor of allergy and infectious disease in the department of global health at the University of Washington in Seattle, enrolled 903 girls between the ages of 11 and 13 at 21 different schools in Vietnam for the study, WebMD Health News reports.

“This study should be very reassuring,” Neuzil, who is also the senior advisor for immunizations at the Seattle-based international nonprofit organization PATH, said, WebMD Health News. “Certainly, clinicians and parents can be reassured that if there are delays, as we know occur, this vaccine still works very well.”

Over 800 of the girls in the study completed all doses of the treatment on one of four different dosing schedules. Girls who were on nine and 12 month dosing schedules as opposed to the recommended six month timetable only had slight dips in their antibody levels.

Those who received the shots over two years had significantly lower antibody levels than the six month gap, but those levels were still higher than seen in studies of older teens and college-aged women.

This lower level of antibodies may still offer protection, but Neuzil said that there is no specific number of antibodies that protects against HPV, WebMD Health News reports.

The study was published in The Journal of the American Medical Association.