Table 2.
Summary of COVID-19 vaccines and evidence of safety and recommendations for use in pregnancy
| Vaccine platform | Commercial developer (candidate name) | Mechanism of action | Assessment of safety in pregnancy | Recommendations for use during pregnancy |
|---|---|---|---|---|
| mRNA | Pfizer/BioNTech (BNT162b2) | Nucleoside-modified mRNA expressed in lipid nanoparticles that encodes the spike protein for the SARS-COV-2 virus | Pfizer/BioNTech commenced a global Phase 3 study recruiting pregnant women in early 2021 | Initial safety data supports the safe use of mRNA vaccines in pregnant women |
| Moderna (mRNA-1237) | Nucleoside-modified mRNA encoding the pre-fusion stabilized spike (S) protein and the S1–S2 cleavage site encapsulated within a lipid nanoparticle | Real-world data from >90,000 women have not identified any safety signals22 | ||
| Nonreplicating viral vector | Oxford-AstraZeneca (AZD1222) | Modified chimpanzee adenovirus (replication deficient) containing the gene encoding the spike (S) protein | Pregnancies that occurred in clinical trials were recorded and followed up until 3 months after birth. Compared with women who received the control vaccine, there was no increased risk of miscarriage and no instances of stillbirth.23 | No previous studies among pregnant women. However, adenovirus-vectored Zika vaccine studies in pregnant mice did not identify any safety signals |
| Janssen (Ad26.COV2.S) | Recombinant, replication-incompetent human adenovirus type 26 that encodes the full length of the stabilized conformation of the spike (S) protein | |||
| Sputnik V (Gam-COVID-Vac) | Combined recombinant adenovirus-based vaccine (rAd5 and rAd26), both containing the gene encoding the full-length spike (S) protein | |||
| Protein subunit | Novavax (NVX-Cov2373) | Full length recombinant spike (S) protein nanoparticle administered with a saponin-based adjuvant (Matrix-M) | No direct safety data available | Recombinant vaccines are generally considered safe for use during pregnancy Safety of saponin-based adjuvant in pregnancy unknown |
| Inactivated whole virus | Sinovac (CoronaVac) | Inactivated whole virus particle containing aluminum hydroxide adjuvant | No direct safety data available | Inactivated vaccines generally considered safe for use during pregnancy. |
| Sinopharm (BBIBP-CorV) | Inactivated whole virus particle containing aluminum hydroxide adjuvant | Aluminum hydroxide (used in human papillomavirus vaccine) and CpG 1018 (used in hepatitis B virus vaccine adjuvants) both considered safe for use during pregnancy | ||
| Valneva (VLA2001) | Inactivated whole virus particle containing aluminum hydroxide and CpG 1018 adjuvants | Safety of the Alhydroxiquim-II adjuvant unknown in pregnancy | ||
| Bharat Biotech (BBV152) | Inactivated whole virus particle containing Alhydroxyquim-II adjuvant |
Adapted from Kalafat et al.21
mRNA, messenger RNA.
Etti. Maternal vaccination. Am J Obstet Gynecol 2022.