Acquisition, prevalence and clearance of type-specific human papillomavirus infections in young sexually active Indian women: A community-based multicentric cohort study.

In context of the ongoing multi-centric HPV vaccine study in India, unvaccinated married women (N = 1484) aged 18-23 years were recruited in 2012-2015 as age-matched controls to the vaccinated women and followed up yearly. We assess type-specific prevalence, natural history and potential determinants of human papillomavirus (HPV) infection in these unvaccinated women. Cervical samples were collected yearly for at least four consecutive years. A Multiplex Type-Specific E7-Based polymerase chain reaction assay was used to detect 21 HPV types. HPV prevalence was 36.4% during 6 years. Most common HPV types were 16 (6.5%) and 31 (6.1%). Highest persistence were observed for HPV 35 (62.5%) and 52 (25%). New HPV acquisition rate was 5.6/1000 person-months of observation (PMO), highest for HPV 16 (1.1/1000 PMO). Type-specific clearance rates ranged between 2.9-5.5/100 PMO. HPV 16 and/or 18 infections were 41% (95% CI 4-63%) lower among women with 2-<3 years between marriage and first cervical sample collection compared to those with <2 years. HPV prevalence and acquisition rates in young Indian women were lower than their Western counterparts. HPV 16 infections being most common shows the importance and potential impact of HPV vaccination in India. Women with 2-3 years exposure had reduced risk possibly due to higher infections clearance

Are two doses of human papillomavirus vaccine sufficient for girls aged 15–18 years? Results from a cohort study in India

Extending two-dose recommendations of HPV vaccine to girls between 15 and 18 years will reduce program cost and improve compliance. Immunogenicity and vaccine targeted HPV infection outcomes were compared between 1795 girls aged 15–18 years receiving two (1–180 days) and 1515 girls of same age receiving three (1–60–180 days) doses. Immunogenicity outcomes in 15–18 year old two-dose recipients were also compared with the 10–14 year old three-dose (N = 2833) and two-dose (N = 3184) recipients. The 15–18 year old two-dose recipients had non-inferior L1-binding antibody titres at seven months against vaccine-targeted HPV types compared to three-dose recipients at 15–18 years and three-dose recipients at 10–14 years of age. Neutralizing antibody titres at 18 months in 15–18 year old two-dose recipients were non-inferior to same age three-dose recipients for all except HPV 18. The titres were inferior to those in the 10–14 year old three-dose recipients for all targeted types. Frequency of incident infections from vaccine-targeted HPV types in the 15–18 year old two-dose recipients was similar to the three dose recipients. None of the girls receiving two or three doses had persistent infection from vaccine-targeted types. These findings support that two doses of HPV vaccine can be extended to girls aged 15–18 years. Keywords: Human papillomavirus, Quadrivalent vaccine, Two doses, age 15–18 years, Immunogenicity, Incident infections, Persistent infection

Impact of age at vaccination and cervical HPV infection status on binding and neutralizing antibody titers at 10 years after receiving single or higher doses of quadrivalent HPV vaccine

Long-term follow-up of a cohort of unmarried girls who received one, two, or three doses of quadrivalent HPV vaccine, between 10 and 18 years of age, in an Indian multi-centric study allowed us to compare antibody responses between the younger and older age cohorts at 10-years post-vaccination, and study the impact of initiation of sexual activity and cervical HPV infections on antibody levels. Among the younger (10–14 years) recipients of a single dose, 97.7% and 98.2% had detectable binding antibody titers against HPV 16 and HPV 18 respectively at ten years post-vaccination. The proportions among those receiving a single dose at age 15–18 years were 92.3% and 94.2% against HPV 16 and HPV 18 respectively. Mean HPV 16 binding antibody titers were 2.1 folds (95%CI 1.4 to 3.3) higher in those vaccinated at ages 10–14 years, and 1.9 folds (95%CI 1.2 to 3.0) higher in those vaccinated at 15–18 years compared to mean titers seen in the unvaccinated women. Compared to previous timepoints of 36 or 48 months, binding antibodies against HPV 16 and neutralizing antibodies against both HPV 16 and HPV 18 were significantly higher at 10 years. This rise was more pronounced in participants vaccinated at 15–18 years. No association of marital status or cervical HPV infections was observed with the rise in titer. Durability of antibody response in single dose recipients correlated well with the high efficacy of a single dose against persistent HPV 16/18 infections irrespective of age at vaccination, as we reported earlier.</p