2-dose HPV vaccine schedule provides sufficient protection for over 2 years: Study
Israel: After the last dose of a 2-dose 9vHPV vaccine regimen in boys and girls, antibody response persists through 2 to 2.5 years, finds a recent study in the journal Pediatrics.
The findings suggests that antibody response generated by administering 2 doses administered 6 to 12 months apart may be sufficient to induce high-level protective efficacy at least for 2 years after the second dose.
A recent international, randomized, open-label trial found human papillomavirus (HPV) antibody responses to the 9-valent human papillomavirus (9vHPV) vaccine among girls and boys (aged 9–14 years) receiving 2-dose regimens (months 0, 6 or 0, 12) to be non inferior to a 3-dose regimen (months 0, 2, 6) in young women (aged 16–26 years) 4 weeks after last vaccination. Jacob Bornstein, Galilee Medical Center and Azrieli Faculty of Medicine, Bar-Ilan University, Nahariya, Israel, and colleagues assessed response durability through month 36.
Girls received 2 (months 0 and 6 [0, 6]: n = 301; months 0 and 12 [0, 12]: n = 151) or 2 doses (months 0,2, and 6 [0, 2, 6]: n = 301). boys received 2 doses ([0, 6]: n = 301; [0, 12]: n = 150); and young women received 3 doses ([0, 2, 6]: n = 314) of 9vHPV vaccine. Using competitive Luminex immunoassay (cLIA) and immunoglobulin G-Luminex immunoassay (IgG-LIA) through month 36, the researchers assessed anti-HPV geometric mean titers (GMTs).
Key findings of the study include:
- Anti-HPV GMTs were highest 1 month after the last 9vHPV vaccine regimen dose, decreased sharply during the subsequent 12 months, and then decreased more slowly. GMTs 2 to 2.5 years after the last regimen dose in girls and boys given 2 doses were generally similar to or greater than GMTs in young women given 3 doses.
- Across HPV types, most boys and girls who received 2 doses (cLIA: 81%–100%; IgG-LIA: 91%–100%) and young women who received 3 doses (cLIA: 78%–98%; IgG-LIA: 91%–100%) remained seropositive 2 to 2.5 years after the last regimen dose.
"In girls and boys, antibody responses generated by 2 doses administered 6 to 12 months apart may be sufficient to induce high-level protective efficacy through at least 2 years after the second dose," wrote the authors.
The study titled, "Three-Year Follow-up of 2-Dose Versus 3-Dose HPV Vaccine," is published in the journal Pediatrics.