Is the Immunization of Pregnant Women against COVID-19 Justified?

Abstract

Maternal immunization against some infectious diseases can offer significant advantages for women, preventing maternal morbidity and mortality, or for offspring, preventing fetal disease and conferring passive immunity to neonates. Recently, clinical trials specifically to evaluate the immunogenicity, safety, and tolerability of some of the available coronavirus disease 2019 (COVID-19) vaccines in pregnant and lactating women have been planned, initiated and, in some cases, completed. This paper discusses whether the immunization of pregnant women against COVID-19 is justified and presents knowledge about the immunogenicity and safety of mRNA COVID-19 vaccines for these subjects. The results of recent studies indicate that pregnant women are at increased risk of developing severe disease compared with nonpregnant women of the same age. Studies carried out with mRNA vaccines indicate that the immunogenicity, safety and tolerability of these preventive measures in pregnant women are not different from those in nonpregnant women of the same age. Moreover, antibodies are efficiently transferred through the placenta and can be detected in breastmilk, suggesting a potential prevention of infection in the child. All these findings authorize the use of mRNA vaccines in pregnant women to protect both the mother and the child. However, further studies with larger sample size and with follow-up of the pregnant women vaccinated during different periods of pregnancy and their children are needed to better characterize the immune response of pregnant women, to define when these vaccines should be administered to obtain the best protection, and to measure vaccine efficacy against virus variants in both mothers and infants. COVID-19 vaccines based on different technological platforms cannot presently be used, and their role in pregnant women should be clarified.

SARS-CoV-2 Vaccines during Pregnancy and Breastfeeding: A Systematic Review of Maternal and Neonatal Outcomes

“…Data from mRNA vaccine studies show that the vaccine safety, tolerability, and efficacy in immunization are similar in pregnant women and their nonpregnant peers [ 4 ]. Since mRNA vaccines appear to stimulate Toll-like receptor 3 and that such activation has been associated with negative gestational outcomes [ 5 ], Shanes et al examined the placentas of 84 women who got a SARS-CoV-2 vaccine during pregnancy and 116 unvaccinated women.…”

“…Given that the incidence of obstetrical complications, such as preterm birth, appears to be proportional to the severity of the infection, infants born to infected mothers with a more severe clinical course may have a worse outcome, mainly due to neonatal morbidity and mortality associated with prematurity. Therefore, the immunization of pregnant women against SARS-CoV-2 appears to be justified [ 4 ].…”

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

“…Pregnant women represent a population that was not included in the initial clinical trials for COVID-19 vaccine authorization due to safety concerns about the new mRNA vaccines [ 18 , 19 ]. However, it is historically proven that vaccination during pregnancy benefits both the mother and the newborn by avoiding the risk of severe disease.…”

Approach of Pregnant Women from Poland and the Ukraine to COVID-19 Vaccination—The Role of Medical Consultation

“…There are many existing arguments indicating the safety of vaccines for COVID-19. Studies on mRNA vaccines allow us to state that the immunogenicity, safety level, as well as tolerability of these precautionary measures taken among pregnant women do not differ from those applied in non-pregnant women at an analogous age [19]. COVID-19 vaccines comprise mRNAs encapsulated in a lipid nanoparticle, which are further transmitted to cells.…”