Immune Response of Two Against Three Doses of Human Papillomavirus Vaccine Studied

Diseases related to the human papillomavirus impose a substantial health care burden on both the developing and developed world.In a study published online by JAMA, Ole-Erik Iversen, of the University of Bergen, Norway, and colleagues examined whether human papillomavirus (HPV) type-specific antibody responses would be noninferior (not worse than) among girls and boys ages nine to 14 years after receiving two doses of the 9-valent HPV vaccine compared with adolescent girls and young women ages 16 to 26 years who received the standard three doses.

For this study, conducted at 52 ambulatory care sites in 15 countries, five groups were enrolled:
(1) girls ages nine to 14 years to receive two doses six months apart (n = 301);
(2) boys ages nine to 14 years to receive two doses six months apart (n = 301);
(3) girls and boys ages nine to 14 years to receive two doses 12 months apart (n = 301);
(4) girls ages nine to 14 years to receive three doses over six months (n = 301); and
(5) a control group of adolescent girls and young women ages 16 to 26 years to receive three doses over six months (n = 314).

Of the 1,518 participants (753 girls [average age, 11.4 years]; 451 boys [average age, 11.5 years]; and 314 adolescent girls and young women [average age, 21 years]), 1,474 completed the study and data from 1,377 were analyzed.

At four weeks after the last dose, the researchers found that HPV antibody responses in girls and boys given two doses were noninferior to HPV antibody responses in adolescent girls and young women given three doses.

The authors write, "In many countries, HPV vaccination rates remain suboptimal. Using an effective two-dose regimen entailing fewer visits could improve adherence to HPV vaccination programs. Co-administration of the 9-valent HPV vaccine with diphtheria, tetanus, pertussis, polio, and meningococcal vaccines could also be completed at the same visit, which has been demonstrated in clinical studies. Based on health economics modeling, use of a 2-dose vaccination schedule could potentially reduce the total costs of HPV vaccination."

Further research is needed to assess persistence of antibody responses and effects on clinical outcomes.

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Source-Eurekalert