COVID vaccination during pregnancy resulted in more lasting antibody levels in infants when compared to babies born unvaccinated, and COVID-infected mothers showed a study.

The study from Massachusetts General Hospital (MGH) showed titers -- or antibody levels -- were higher in vaccinated mothers and their umbilical cord blood at delivery than in those study participants infected with COVID. After two months, 98 per cent of the infants (48 of 49) born to vaccinated mothers had detectable levels of the protective Immunoglobulin G (IgG), the most common antibody found in the blood.

At six months, the researchers looked at 28 of the infants born to vaccinated mothers and found 57 per cent (16 of 28) still had detectable IgG. That was compared with just 8 per cent (1 of 12) born to infected mothers. "While it's still unclear just how high the titer needs to be to completely protect an infant from COVID, we know anti-spike IgG levels correlate with protection from serious illness," said Andrea Edlow, Maternal-Foetal Medicine specialist at MGH.

"The durability of the antibody response here shows vaccination not only provides lasting protection for mothers but also antibodies that persist in a majority of infants to at least six months of age," Edlow added. The study, published in The Journal of the American Medical Association (JAMA), included individuals vaccinated with two doses of an mRNA vaccine or infected at 20 to 32 weeks gestation when a transfer of antibodies through the life-giving placenta has shown to be at its peak.

Several studies have shown that pregnant women are at extremely high risk for serious complications from COVID. A recent study led by a University of Utah Health obstetrician showed that pregnant individuals infected with SARS-CoV-2 are about 40 per cent more likely to develop serious complications or die during pregnancy than those who aren't infected with the virus.

Another study led by the US National Institutes of Health showed that pregnant women with moderate to severe COVID infection were more likely to have a cesarean delivery, to deliver preterm, to die around the time of birth, or to experience serious illness from hypertensive disorders of pregnancy, postpartum haemorrhage, or from infection other than SARS-CoV-2.

According to Galit Alter, from the Ragon Institute of MGH, MIT and Harvard, "given the lag in the development of COVID-19 vaccines for infants, these data should motivate mothers to get vaccinated and even boosted during pregnancy to empower their babies' defences against COVID."