A study published in The BMJ showed two doses of the mRNA COVID-19 vaccine given to pregnant women were 95% successful in preventing infant infection from the delta variation and 45% effective in preventing infant infection from the omicron variant.

8,809 children under the age of six months who were born between May 7, 2021, and March 31, 2022, and were tested for COVID-19 between May 7, 2021, and September 5, 2022, were evaluated in the study.

Further more specifically 99 instances of COVID-19 with the delta variation (with 4,365 controls) and 1,501 cases of omicron variant infection (with 4,847 controls) were included in the study. The primary outcome was infection due to delta or omicron variants or hospitalization.

Results showed maternal vaccination reduced hospitalization by 97% and 53% in delta and omicron types, respectively. Three doses prevented 80% of hospitalization against omicron-related and 73% of hospitalization due to omicron infection among infants. The effectiveness of three dosages against the delta variation was not available.

The vaccines effectiveness against newborn omicron infection was at its best when pregnant women received the second dose of the vaccination during the third trimester of pregnancy as opposed to the first or second trimesters of pregnancy.

The effectiveness of the two-dose vaccine against infant infection with omicron peaked in the first eight weeks of life (57%), then fell to 40% in infants older than 16 weeks.

Experts stated that the current study confirms the benefits of immunization during pregnancy. The maternal vaccinations efficacy against other COVID-19 strains, including BQ.1, BQ.1.1, BF.7, XBB, and XBB.1 is still unknown. More studies are required to evaluate the effectiveness of the bivalent mRNA vaccines protective effects (as opposed to the primary monovalent vaccine in the current trial) and the possible advantages of future boosters.

(Source: https://www.medscape.com/viewarticle/988117?src=#vp_1)