Three or more maternal doses of COVID-19 vaccine enhance newborn protection – Healio

January 19, 2024

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Three or more doses of maternal COVID-19 vaccine significantly enhance antibody concentrations in preterm infants compared with two or fewer doses, according to study results published in JAMA Network Open.

The authors noted that COVID-19 vaccines have been instrumental in decreasing morbidity and mortality from SARS-CoV-2 infection during pregnancy.

COVID-19 vaccines induce anti-spike (anti-S) antibody production in pregnant individuals that, similarly to antibodies against other respiratory infections, such as influenza, are able to cross the placenta via active transplacental antibody transfer, they wrote.

They also noted that although COVID-19 vaccines given to pregnant people may project infants from severe illness through transplacental transfer of the maternal antibody IgG,

Few data exist on maternally derived SARS-CoV-2 antibody in infants born prematurely.

Our objective was to evaluate anti-S antibody among paired maternal samples and cord samples from preterm and full-term deliveries, they wrote.

They conducted a prospective cohort study of 220 pregnancies 36 infants born preterm and 184 born full-term and found that receipt of three or more doses of COVID-19 vaccine before delivery resulted in 10-fold higher cord anti-S antibody levels compared with receipt of two doses.

Before delivery, 121 pregnant people received two vaccine doses and 99 received three or more. The two-dose group had a geometric mean concentration of maternal anti-S antibodies amounting to 674 (95% CI, 577-787), whereas the three-dose group had a concentration of 8,159 (95% CI, 6,636-10,032).

Cord anti-S antibody geometric mean concentration was 1,000 (95% CI, 874-1,144) after two doses and 9,992 (95% CI, 8381-1,1914) after three or more doses. Following adjustment for vaccine timing and number of doses before delivery, the researchers found no association between preterm delivery and cord anti-S antibody levels (=0.44; 95% CI, 0.06 to 0.94).

Maternal antibody concentration appeared more important than delivery gestational age in determining cord anti-spike antibody levels, the authors wrote. The number of doses and timing considerations for COVID-19 vaccine in pregnancy should include individuals at risk for preterm delivery.

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Three or more maternal doses of COVID-19 vaccine enhance newborn protection - Healio