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

Defining and reporting adverse events of special interest in comparative maternal vaccine studies: a systematic review

Introduction

The GAIA (Global Alignment on Immunisation Safety Assessment in Pregnancy) consortium was established in 2014 with the aim of creating a standardised, globally coordinated approach to monitoring the safety of vaccines administered in pregnancy. The consortium developed twenty-six standardised definitions for classifying obstetric and infant adverse events. This systematic review sought to evaluate the current state of adverse event reporting in maternal vaccine trials following the publication of the case definitions by GAIA, and the extent to which these case definitions have been adopted in maternal vaccine safety research.

Methods

A comprehensive search of published literature was undertaken to identify maternal vaccine research studies. PubMed, EMBASE, Web of Science, and Cochrane were searched using a combination of MeSH terms and keyword searches to identify observational or interventional studies that examined vaccine safety in pregnant women with a comparator group. A two-reviewer screening process was undertaken, and a narrative synthesis of the results presented.

Results

14,737 titles were identified from database searches, 435 titles were selected as potentially relevant, 256 were excluded, the remaining 116 papers were included. Influenza vaccine was the most studied (25.0%), followed by TDaP (20.7%) and SARS-CoV-2 (12.9%).Ninety-one studies (78.4%) were conducted in high-income settings. Forty-eight (41.4%) utilised electronic health-records. The majority focused on reporting adverse events of special interest (AESI) in pregnancy (65.0%) alone or in addition to reactogenicity (27.6%). The most frequently reported AESI were preterm birth, small for gestational age and hypertensive disorders. Fewer than 10 studies reported use of GAIA definitions. Gestational age assessment was poorly described; of 39 studies reporting stillbirths 30.8% provided no description of the gestational age threshold.

Conclusions

Low-income settings remain under-represented in comparative maternal vaccine safety research. There has been poor uptake of GAIA case definitions. A lack of harmonisation and standardisation persists limiting comparability of the generated safety data.

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.

Early exploration of COVID-19 vaccination safety and effectiveness during pregnancy: interim descriptive data from a prospective observational study

Objective

During December 2020, a massive vaccination program was introduced in our country. The Pfizer-BioNTech, BNT162b2 vaccine was first offered exclusively to high-risk population, such as medical personnel (including pregnant women). In this study we compare short term outcomes in vaccinated vs. non-vaccinated pregnant women.

Methods

In this prospective observational cohort study, vaccinated and non-vaccinated pregnant women were recruited using an online Google forms questionnaire targeting medical groups on Facebook and WhatsApp. A second questionnaire was sent one month after the first one for interim analysis. Our primary outcome was composite complications in vaccinated and non-vaccinated groups, considered any of the following: vaginal bleeding, pregnancy loss, hypertension, gestational diabetes, and preterm birth. Secondary outcomes included: vaccine side effects, diagnosis of COVID-19 since the last questionnaire, prevalence of vaccinated participants, and reasons for refusal to be vaccinated.

Results

Overall, 432 women answered the first questionnaire, of which 326 responses were received to the second questionnaire. Vaccination rate increased from 25.5% to 62% within a month. Maternal age, gestational age at enrollment, nulliparity and number of children were similar in both groups. The rate of composite pregnancy complications was similar between vaccinated and non-vaccinated group (15.8% vs 20.1%, p = 0.37), respectively. The risk for COVID-19 infection was significantly lower in the vaccinated group (1.5% vs 6.5%, p = 0.024, Odds Ratio: 4.5, 95% confidence interval 1.19–17.6).

Conclusions

mRNA vaccine during pregnancy does not seem to increase the rate of pregnancy complications and is effective in prevention of COVID-19 infection.

The impact of HPV vaccination beyond cancer prevention: effect on pregnancy outcomes

While the benefits of human papillomavirus (HPV) vaccination relating to cervical cancer prevention have been widely documented, recent published evidence is suggestive of an impact on adverse pregnancy outcomes (APOs) in vaccinated mothers and their infants, including a reduction in rates of preterm births and small for gestational age infants. In this review, we examine this evidence and the possible mechanisms by which HPV vaccination may prevent these APOs. Large-scale studies linking HPV vaccination status with birth registries are needed to confirm these results. Potential confounding factors to consider in future analyses include other risk factors for APOs, and historical changes in both the management of cervical precancerous lesions and prevention of APOs. If confirmed, these additional benefits of HPV vaccination in reducing APO rates will be of global significance, due to the substantial health, social and economic costs associated with APOs, strengthening the case for worldwide HPV immunization.

Mandatory HPV Vaccination; Opportunity to Save Lives, Improve Readiness and Cut Costs

Human papillomavirus (HPV) is the most common sexually transmitted infection (STI) in the U.S. military and accounts for more healthcare visits than the next two most common STIs combined. Human papillomavirus is preventable with a safe, effective, prophylactic vaccine that has been available since 2006, yet vaccination rates remain low. The vaccine is approved for females and males aged 9-45 years for prevention of HPV-related dysplasia and cancers. Although it is recommended by the Centers for Disease Control and Prevention (CDC)'s Advisory Committee on Immunization Practices (ACIP), it is not part of the U.S. military's mandatory vaccine list. Human papillomavirus does not just affect female service members-male service members have a higher reported seropositive rate than their civilian counterparts and can develop oropharyngeal, anal, or penile cancers as sequelae of HPV. Oropharyngeal cancer, more common in males, is the fastest growing and most prevalent HPV-related cancer in the USA. Several countries, such as Australia and Sweden, have successfully implemented mandatory vaccine programs and have seen rates of HPV-related diseases, including cancer, decline significantly. Some models project that cervical cancer, which is the fifth-most common cancer in active duty women, will be eliminated in the next 20 years as a result of mandatory vaccination programs. Between higher seropositive rates and lack of widespread vaccination, HPV dysplasia and cancer result in lost work time, decreased force readiness, negative monetary implications, and even separation from service. With more than half of the 1.3 million service members in the catch-up vaccination age range of less than 26 years of age, we are poised to have a profound impact through mandatory active duty service member vaccination. Although multiple strategies for improving vaccination rates have been proposed, mandatory vaccination would be in line with current joint service policy that requires all ACIP-recommended vaccines. It is time to update the joint service guidelines and add HPV vaccine to the list of mandatory vaccines.

Has the human papillomavirus (HPV) immunization programme improved obstetric outcomes in spontaneous delivery? An ecological study

OBJECTIVE

To measure the rates of adverse obstetric outcomes in spontaneous delivery in a population of young women with high uptake of the bivalent human papillomavirus (HPV) vaccine.

STUDY DESIGN

This was a population-based ecological study with data from the Aberdeen Maternity and Neonatal Databank, UK. All women born between 1986-1996 with spontaneous singleton live birth at age 20-30 years were included for analysis. Exposure was defined according to maternal year of birth and HPV immunisation eligibility: pre-immunisation cohort (1986-1990), catch-up immunisation cohort (1991-1994) and routine immunisation cohort (1995-1996). Outcomes were defined as spontaneous preterm birth (PTB), low birth weight (LBW) and pre-labour preterm rupture of membranes (pPROM). Generalized estimating equation models were applied, adjusted for deprivation, smoking status, marital status, body mass index, parity, maternal age and year of infant delivery.

RESULTS

A total of 6515 spontaneous singleton live births were included in final analysis, with 5134 births included in the pre-immunisation cohort, 1250 in the catch-up immunisation cohort and 131 in the routine immunisation cohort. Compared with the pre-immunisation cohort, no statistically significant reduction on PTB, LBW or pPROM were observed in either immunised cohorts. The adjusted odds ratio (aOR) on PTB was 0.64 (95 % confidence interval, 0.40-1.03) in the catch-up cohort and 0.71 (0.28-1.77) in the routine cohort. The corresponding aOR were 0.88 (0.54-1.45) and 0.51 (0.16-1.62) for LBW and 1.62 (0.58-4.54) and 1.51 (0.21-11.01) for pPROM.

CONCLUSIONS

We did not observe a significant reduction on PTB, LBW or pPROM among spontaneous singleton live birth in either HPV immunised cohorts, although the additional benefit in improving obstetric outcomes cannot be excluded because of the limits of the sample size and the study design. Further demonstration is warranted when more women in the fully HPV immunised cohorts embark on pregnancy.