Study Finds Vaccinated Pregnant People Pass COVID Antibodies to Newborns

Another great reason to get the shot if you’re expecting.

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redscale edit of a pregnant person holding their baby bump while wearing a mask

COVID vaccines won’t be available for kids under age 5 for several more weeks, if not months. Even then, infants will have to wait until they’re 6 months old to get the shot. But that doesn’t mean babies are forever doomed to be vulnerable to the COVID-19 pandemic. Vaccinated pregnant people naturally transfer high levels of antibodies to their newborns, according to a new study.

Researchers tested 36 babies born to a parent who was vaccinated with either the Pfizer or Moderna vaccine. They found that a whopping 100 percent of those newborns had high levels of antibodies from the vaccine. “We didn’t anticipate that. We expected to see more variability,” Ashley Roman, MD, an obstetrician at NYU Langone Health System and co-author of the study, told Bloomberg.

Roman’s team tested umbilical cord blood for two types of antibodies at birth. One of those antibodies, to the spike protein on the coronavirus, is generated after both COVID infection and vaccination. But the other antibodies, to the so-called nucleocapsid protein, only show up after infection. Tests for the latter in all 31 of the newborns came back negative. This proves that the pregnant parents passed protection from COVID to their babies due to their vaccination — and not because they had developed natural immunity after being infected by the virus.

The new study was small, but Roman’s team is continuing their research in a larger sample. “We pushed this data out relatively early because it’s a unique finding and it has important implications for care,” she said. It’s unclear how long immunity lasts in the newborns — a question that further research will hopefully answer.

“Studies continue to reinforce the importance of vaccines during pregnancy and their power to protect two lives at once by preventing severe illness in both mothers and babies,” Roman said in a statement. “If babies could be born with antibodies, it could protect them in the first several months of their lives, when they are most vulnerable.”

What can pregnant people do with this information? “This is another reason pregnant women should get vaccinated, as we are seeing more disease in younger infants and this is a proactive choice pregnant individuals can make to protect their infants,” Linda Eckert, MD, an OB/GYN at the University of Washington who wasn’t involved in the study, told Bloomberg.

The Centers for Disease Control and Prevention recommends the vaccine during pregnancy, and studies have found that it is safe for both parent and child. However, only about 30 percent of pregnant people aged 18 to 49 were vaccinated as of September 11, according to data from the CDC.

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