Is administration of the HPV vaccine during pregnancy feasible in the future?

Association of periconceptional or pregnancy exposure of HPV vaccination and adverse pregnancy outcomes: a systematic review and meta-analysis with trial sequential analysis

Objective: To evaluate whether periconceptional or pregnancy exposure of human papillomavirus (HPV) vaccination would increase the risk of adverse pregnancy outcomes. Methods: The PubMed, Web of Science, Embase, the Cochrane Library of clinical trials were searched from inception to March 2023. We computed relative risk (RR) and 95% confidence intervals (CIs) and prediction intervals (PIs) regarding the association between HPV vaccination in periconceptional period or during pregnancy and the risks of adverse pregnancy outcomes by using R software Version 4.1.2 and STATA Version 12.0. A trial sequential analysis (TSA) was performed with TSA v0.9.5.10 Beta software. Results: Four randomized controlled trials (RCTs) and eight cohort studies were included in this meta-analysis. Analysis of RCTs showed that HPV vaccination in periconceptional period or during pregnancy did not increase the risks of spontaneous abortion (RR = 1.152, 95% CI: 0.909-1.460, 95% PI: 0.442-3.000), birth defects (RR = 1.171, 95% CI: 0.802-1.709, 95% PI: 0.320-4.342), stillbirth (RR = 1.053, 95% CI: 0.616-1.800, 95% PI: 0.318-3.540), preterm birth (RR = 0.940, 95% CI: 0.670-1.318) and ectopic pregnancy (RR = 0.807, 95% CI: 0.353-1.842, 95% PI: 0.128-5.335). In cohort studies, periconceptional or pregnancy exposures of HPV vaccine were not associated with the increased risk of spontaneous abortion (RR = 0.987, 95% CI: 0.854-1.140, 95% PI: 0.652-1.493), birth defects (RR = 0.960, 95% CI: 0.697-1.322, 95% PI: 0.371-2.480), stillbirth (RR = 1.033, 95% CI: 0.651-1.639, 95% PI: 0.052-21.064), small size for gestational age (SGA) (RR = 0.971, 95% CI: 0.873-1.081, 95% PI: 0.657-1.462) and preterm birth (RR = 0.977, 95% CI: 0.874-1.092, 95% PI: 0.651-1.444). Conclusion: HPV vaccine exposures in periconceptional period or during pregnancy did not increase the risks of adverse pregnancy outcomes, including spontaneous abortion, birth defects, stillbirth, SGA, preterm birth and ectopic pregnancy. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42023399777.

Maternal and infant outcomes following exposure to quadrivalent human papillomavirus vaccine during pregnancy

INTRODUCTION

The Department of Defense encourages service members ≤26 years of age to receive the human papillomavirus (HPV) vaccine. Although this vaccine is not recommended in pregnancy, inadvertent vaccination may occur. The objective of this study was to assess whether active duty US military women who received the quadrivalent HPV vaccine (4vHPV) during pregnancy were at increased risk for adverse maternal or infant outcomes.

METHODS

The study population included active duty US military women aged 17-28 years with at least one pregnancy between 2007 and 2014, and the infants resulting from those pregnancies. Pregnancies, live births, and outcomes were identified using medical codes in administrative medical records. Exposure to 4vHPV during pregnancy was ascertained from personnel immunization records. Multivariable regression models were used to calculate risk estimates and 95% confidence intervals for the maternal outcomes of spontaneous abortion, preeclampsia/eclampsia and preterm labor, and the infant outcomes of preterm birth, birth defects, growth problems in infancy or in utero, and infant sex.

RESULTS

Overall, 90,600 pregnancies and 75,670 singleton infants were identified. Approximately 2% of pregnancies and infants were exposed to 4vHPV during pregnancy. After adjustments, no positive associations were detected between inadvertent exposure to 4vHPV during pregnancy and any adverse pregnancy or infant outcomes.

DISCUSSION

Our findings add to an established body of literature demonstrating the safety of 4vHPV when inadvertently administered during pregnancy. Although 4vHPV is no longer administered in the US, its use continues overseas; therefore, safety studies remain important. Furthermore, such studies can provide reassurance to women inadvertently exposed to nonavalent HPV vaccine (9vHPV) in pregnancy, which protects against four of the same antigens as 4vHPV, since safety of 9vHPV has not yet been established in pregnant women.

The association between adverse pregnancy outcomes and maternal human papillomavirus infection: a systematic review protocol

BACKGROUND

Human papillomavirus (HPV) is the most prevalent genital infection, especially in young women of reproductive age. In vitro and animal model experiments provide compelling evidence of the harmful effect of HPV on pregnancy outcomes, but results from epidemiologic studies are inconclusive. We aim to determine the strength of the relationship between adverse pregnancy outcomes (APO) and HPV infection and assess its consistency across studies, by systematically reviewing the literature.

METHODS

The search strategy has been developed on the basis of the PICOS framework: Population (pregnant women); Exposure (HVP infection confirmed by HPV testing); Comparator (pregnant women without HPV infection); Outcomes (miscarriage, spontaneous preterm birth, low birth weight, preterm premature rupture of membranes, pregnancy-induced hypertensive disorders and intrauterine growth restriction) and Study design (observational studies). We will search three information sources: (1) electronic databases (MEDLINE, EMBASE, and EBM Reviews databases); (2) Grey literature (Google Scholar and Web of Science conference proceedings); and (3) citing and cited articles of included studies. Two reviewers (JN, NZ) will independently and in duplicate screen identified articles, select eligible studies, and extract data. Discrepancies will be resolved by consensus and otherwise by discussion with the other authors (MHM, HT). Quality of included studies will be assessed using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies. We will narratively synthesize extracted data whether meta-analysis is conducted or not. Meta-analysis of each outcome will be performed, and where appropriate, an average measure of association will be computed. We will use the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess and grade the strength of confidence in cumulative estimate.

DISCUSSION

Comprehensive and high-quality evidence of a negative effect of HPV on pregnancy outcomes might be an additional motivation for HPV vaccination. Absence of such relationship could dispel anxiety and reassure HPV-infected pregnant women and clinicians. Findings of a poor level of confidence will allow identification of current knowledge gaps on HPV-pregnancy outcome relationship that need further research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016033425.

Recent progress in vaccination against human papillomavirus-mediated cervical cancer

It has been more than 7 years since the commercial introduction of highly successful vaccines protecting against high-risk human papillomavirus (HPV) subtypes and the development of cervical cancer. From an immune standpoint, the dependence of cervical cancer on viral infection has meant that HPV proteins can be targeted as strong tumour antigens leading to clearance of the infection and the subsequent protection from cancer. Commercially available vaccines consisting of the L1 capsid protein assembled as virus-like particles (VLPs) induce neutralising antibodies that deny access of the virus to cervical epithelial cells. While greater than 90% efficacy has been demonstrated at the completion of large phase III trials in young women, vaccine developers are now addressing broader issues such as efficacy in boys, longevity of the protection and inducing cross-reactive antibody for oncogenic, non-vaccine HPV strains. For women with existing HPV infection, the prophylactic vaccines provide little protection, and consequently, the need for therapeutic vaccines will continue into the future. Therapeutic vaccines targeting HPVE6 and E7 proteins are actively being pursued with new adjuvants and delivery vectors, combined with an improved knowledge of the tumour microenvironment, showing great promise. This review will focus on recent progress in prophylactic and therapeutic vaccine development and implementation since the publication of end of study data from phase III clinical trials between 2010 and 2012.