Covid-19 Vaccination in Pregnancy: A Systematic Review

Abstract

Objective: Pregnancy is a risk factor for severe Covid-19. Looking for safe vaccines that evoke protective maternal and fetal antibody response is important. Methods: We searched from registries (ClinicalTrials.gov, the WHO Clinical Trial Registry, and the EU Clinical Trial Registry) and databases (MEDLINE, ScienceDirect, Cochrane Library, Proquest, and Springer) up until June 20, 2021. Articles were selected based on inclusion and exclusion criteria after duplicates were removed. Infection rate, maternal antibody response, placental antibody transfer, and adverse events were described. This systematic review was performed with quality assessment and semi-quantitative synthesis according to PRISMA guidelines. Results: Twelve observational studies with a total of 40.509 pregnant women included. The mRNA based vaccines (Pfizer-BioNTech and Moderna) can prevent future SARS-CoV-2 infections (p=0.0004). Both vaccines did not affect pregnancy, delivery, and neonatal outcomes. The most commonly encountered adverse reactions are injection-site pain, fatigue, and headache but only transient. Antibody responses were rapid after the prime dose of vaccines. After booster, antibody responses were higher and associated with better placental antibody transfer. Longer intervals between first vaccination dose and delivery were also associated with higher antibody fetal IgG and better antibody transfer ratio. Conclusions: The Pfizer-BioNTech and Moderna vaccines are efficacious for preventing future SARS-CoV-2 infections. These vaccines can be considered as a safe option for pregnancy and their fetus. Two doses of vaccines were recommended for more robust maternal and fetal antibody responses. Longer latency was associated with higher fetal antibody responses.

The Risk of Spontaneous Abortion Does Not Increase Following First Trimester mRNA COVID-19 Vaccination

“…A bigger study that took place in the US reviewed the safety of mRNA vaccination against SARS-CoV-2 during all trimesters of pregnancy, or just before conception [ 30 ]. They reported that the distribution of negative pregnancy and birth complications such as fetal loss, preterm birth, small size for gestational age, congenital abnormalities, and stillbirths among participants with completed pregnancies was comparable to previously published rates in pregnant populations studied prior to the COVID-19 pandemic [ 31 , 32 , 33 ]. The largest study to date included a review of almost fifty thousand pregnant women who received mRNA vaccines for COVID-19.…”

Systematic review of the safety, immunogenicity, and effectiveness of COVID‐19 vaccines in pregnant and lactating individuals and their infants

“…A systematic review on COVID‐19 vaccination in pregnancy was recently published on MedRxiv 38 . That review limited their analysis to pregnant populations and included 12 observational studies, two of which were not included here because they had less than 10 participants.…”

Vaccines for Covid‐19: An insight on their effectiveness and adverse effects

“…Following these vaccinations, most pregnant females showed injection‐site pain/soreness, headache, fatigue, chills, fever, myalgia, and nausea. 67 …”