Immunogenicity of 2-Dose HPV Vaccine Series for Postpartum Women

Abstract

ImportancePostpartum human papillomavirus (HPV) vaccination is a promising strategy to increase HPV vaccination uptake in the US, particularly for reaching vaccine-naive women and those who lack health insurance beyond the pregnancy period. However, completion of the 3-dose vaccine regimen is challenging.ObjectiveTo evaluate the immunogenicity of a 2-dose postpartum HPV vaccination regimen (0 and 6 months) and assess whether it is noninferior to a 3-dose postpartum HPV vaccination regimen (0, 1-2, and 6 months) administered to historical controls.Design, Setting, and ParticipantsA noninferiority, open-label, nonrandomized immunogenicity trial was conducted from August 4, 2020, to June 23, 2022, of postpartum patients aged 15 to 45 years who delivered at 2 hospitals in Baltimore, Maryland. Historical controls were adolescents and young women aged 16 to 26 years.InterventionTwo doses of the nonavalent HPV vaccine administered 6 months apart.Main Outcomes and MeasuresThe primary outcome was noninferiority (90% CI, lower bound >0.67) of the geometric mean titer (GMT) ratio for HPV-16 among postpartum women compared with historical controls. Secondary outcomes were noninferiority of GMT ratios for the other 8 HPV types and percentage seroconversion for each HPV type. As a noninferiority trial, the primary analysis used the per-protocol analysis.ResultsOf 225 enrolled participants, the mean (SD) age at baseline was 29.9 (6.8) years, and 171 (76.0%) were HPV-16 seronegative at baseline. Of these 171 participants, 129 (75.4%) received a second vaccine dose and completed the subsequent 4-week serologic measurements. Relative to historical controls, the HPV-16 GMT ratio was 2.29 (90% CI, 2.03-2.58). At month 7, HPV-16 GMT was higher after the 2-dose regimen (7213.1 mMU/mL [90% CI, 6245.0-8331.4 mMU/mL]) than among historic controls after the 3-dose regimen (3154.0 mMU/mL [90% CI, 2860.2-3478.0 mMU/mL]). Similarly, the lower bound of the 90% CI of the GMT ratio was above 1 for the 8 HPV types 6, 11, 18, 31, 33, 45, 52, and 58. A total of 118 of 134 women (88.1%) seroconverted for HPV-16 after the first dose; 4 weeks after the second dose, the seroconversion rate was 99% or greater for all HPV types.Conclusions and RelevanceThis study suggests that immunogenicity of a 2-dose HPV vaccination regimen given 6 months apart among postpartum women was noninferior to a 3-dose regimen among young historical controls. Most women seroconverted after the first dose of the 2-dose regimen. These results demonstrate that postpartum vaccination using a reduced schedule may be a promising strategy to increase HPV vaccine series completion.Trial RegistrationClinicalTrials.gov Identifier: NCT04274153

Updates on Human Papillomavirus Vaccination and Impact on Prevention of Invasive Cervical Cancer

“…Further, data in 2024 have demonstrated that the 2-dose vaccine schedule was noninferior to the 3-dose vaccine in postpartum patients aged 15 to 46 years, although this recommendation is not officially endorsed. 23 At this time, the WHO recommends a 3-dose vaccination schedule in persons 15 years or older, or those younger than 15 years known to be immunocompromised by disease such as HIV. 24 Currently, there is no established evidence to support a booster vaccination.…”

Updates on Human Papillomavirus Vaccination and Impact on Prevention of Invasive Cervical Cancer

“…Further, data in 2024 have demonstrated that the 2-dose vaccine schedule was noninferior to the 3-dose vaccine in postpartum patients aged 15 to 46 years, although this recommendation is not officially endorsed. 23 At this time, the WHO recommends a 3-dose vaccination schedule in persons 15 years or older, or those younger than 15 years known to be immunocompromised by disease such as HIV. 24 Currently, there is no established evidence to support a booster vaccination.…”