Researchers found that vaccination for HPV should be given in 2 doses, at least 6 months apart for routine vaccinations of young girls.1 These results support the guidelines recommended by the World Health Organization.
In a multicenter prospective cohort study, investigators in India sought to determine if the immunogenicity and frequency of persistent infection and cervical precancerous lesions caused by HPV following vaccination with 3 doses on days 1, 60, and 180 or later; 2 doses on days 1 and 180 or later, 2 doses on days 1 and 60 by default, and 1 dose by default.
A total of 17 729 girls aged 10 to 18 years were recruited for the study: 4348 (25%) received 3 doses, 4979 (28%) received 2 doses on days 1 and 180 or later, 3452 (19%) received 2 doses at days 1 and 60, and 4950 (28%) received 1 dose.
At 7-months follow-up, immune response was similar in the 2-dose HPV group and the 3-dose group (median fluorescence intensity ratio for HPV 16 1.12 [95% CI, 1.02 – 1.23] and for HPV 18 1.04 [95% CI, 0.92 – 1.19]). However, the 2-dose group was inferior to the 3-dose group at 18 months follow-up.
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Neutralizing antibodies against the 4 types of HPV were found in all groups, but at a lower concentration in girls who received 1 dose. Cervical samples were taken from 2649 participants and the frequency of incident HPV 16, 18, 6, and 11 was similar regardless of number of doses taken. There was no persistent HPV 16 or 18 infections in any study group at a median follow-up of 4.7 years.
The authors concluded that the short-term benefits of 1 dose of HPV vaccine is similar to the benefits provided by 2 or 3 doses of vaccine and that further study should be performed.
- Sankaranarayanan R, Prabhu, PR, Pawlita, M, et al. Immunogenicity and HPV infection after one, two, and three doses of quadrivalent HPV vaccine in girls in India: a multicentre prospective cohort study [published online ahead of print December 1, 2015]. Lancet Oncol. doi: 10.1016/S1470-2045(15)00414-3.