2-Dose HPV Vaccine Postpartum Equally Effective as 3-Dose

A 2-dose regimen of vaccination against human papillomavirus (HPV) in postpartum individuals is equally effective compared to a 3-dose regimen, according to a recent study published in JAMA Network Open.1

Approximately 330,000 cases of precancerous cervical dysplasia and 12,000 cases of cervical cancer in the United States per year are attributed to HPV. Vaccination against HPV is recommended in individuals aged 11 to 12 years by the Centers for Disease Control and Prevention (CDC).

Only 49% of adolescents have received HPV vaccination. However, delayed vaccination remains effective in sexually active women. Therefore, the CDC recommends potential discussion about HPV vaccination in patients aged up to 45 years.

To ensure the greatest efficacy from HPV vaccination regimens, the immunogenicity should be evaluated. To compare the immunogenicity of a 2-dose regimen vs a 3-dose regimen among postpartum women, investigators conducted an open-label, nonrandomized, noninferiority clinical trial.

As optimal antibodies develop within 4 to 6 months, regimens had patients receive the second dose 6 months after the first. Historical controls included patients aged 16 to 26 years, while postpartum participants were aged 15 to 49 years.

Exclusion criteria included severe allergy related to vaccination, any prior HPV vaccination, latex or yeast allergy, fetal demise or stillbirth, moderate or severe peripartum acute illness, concurrent COVID-19 vaccine administration, and immunosuppression.

Enrollment occurred in the third trimester or immediate postpartum period. Demographic information, including self-reported race and ethnicity, was collected during a counseling and content session with a research coordinator.

During the first visit at baseline, the first vaccine dose was administered. After 6 weeks, the second visit occurred, and patients received the second dose. The third visit occurred at least 4 weeks after the second, during which vaccination was not administered.

The final vaccination dose was administered during the fourth visit, occurring 1 to 5 months after the third visit. Whole blood was drawn at each of the first 3 visits.

The geometric mean titer(GMT) ratio for HPV type 16 was the primary outcome of the analysis, measured before the first vaccine dose and 4 weeks after the second dose. GMT ratios for other HPV types in the vaccine were measured as secondary outcomes.

There were 225 patients included in the final analysis, aged a mean 29.9 years. Two received vaccine doses were reported by 77.3% of participants and 3 doses by 39.6%.

Negative results for HPV-16 were reported in 76% of participants at baseline, 75.4% of whom received 2 doses and underwent serologic measurements. An HPT-16 GMT of 7213.1mMU/mL was reported among these women.

In comparison, historic controls who had 3 doses had an HPT-16 GMT of 3154.0mMU/mL, indicating a GMT ratio of 2.29. Additionally, all HPV types had higher GMTs at month 7 from a 2-dose regimen compared to a 3-dose regimen. At the 7-month follow-up, seroconversion was reported in all participants with 2 doses and who were seronegative for HPV-16 at baseline.

These results indicated efficacy from a 2-dose vaccine regimen in protecting patients from HPC. Investigators recommended further research to replicate these findings.

This article originally appeared on Contemporary OB/GYN.

Reference

1. Moss CF, Wang R, Sao S, et al. Immunogenicity of 2-Dose HPV vaccine series for postpartum women: An open-label, nonrandomized, noninferiority trial. JAMA Netw Open. 2024;7(1):e2352996. doi:10.1001/jamanetworkopen.2023.52996