Washington, September 23rd
Women who receive the mRNA COVID-19 vaccine during pregnancy pass on high levels of antibodies to their babies, according to a study.
The effectiveness of COVID-19 vaccines lies in their ability to trigger the production of the right antibodies, blood proteins that can protect individuals from infection, researchers said.
Whether this protection could pass from mothers to their babies before birth, a question remained, they said.
The study, published Wednesday in the American Journal of Obstetrics & Gynecology Maternal-Fetal Medicine, was conducted on 36 newborns whose mothers received the Pfizer or Modern COVID-19 vaccine during pregnancy.
The research team led by NYU Grossman School of Medicine in the US found that 100 percent of babies had protective antibodies at birth.
Antibodies may or may not be produced as part of the natural response to infection when activated by vaccines.
Although the sample size is small, “it is encouraging that neonatal antibody levels are high when women are vaccinated,” said Jennifer L Lighter, a professor at Hassenfeld Children’s Hospital in NYU Langone, and the study’s senior author.
The team was able to secrete antibodies into the neonatal blood that were made in response to natural infection from those made in response to the vaccines.
The researchers noted that the result is relevant because natural antibody responses to the SARS-CoV-2 virus, which causes COVID-19, are not sufficiently protective for many people.
Recent data from the U.S. Centers for Disease Control and Prevention (CDC) suggests that only 23 percent of pregnant women are vaccinated, despite increasing evidence of prenatal vaccine safety.
The researchers observed the highest levels of antibodies in cord blood of mothers who were fully vaccinated in the second half of their pregnancy.
This insight provides evidence of transferred immunity to neonates, which correlates with protection against infection for infants in the first months of life, they said.
“Studies continue to reinforce the importance of vaccines during pregnancy and their ability to protect two lives at once by preventing serious illness in both mothers and babies,” said Ashley S Roman, professor at NYU Langone Health, and one of the lead researchers at the study.
“If babies can be born with antibodies, it can protect them in the first several months of their lives, if they are the most vulnerable,” Roman said.
Roman and colleagues confirmed the strong evidence that the mRNA vaccines are safe during pregnancy in a study published on August 16 in the same journal.
That study found no increased risks during pregnancy, birth complications, or identifiable risks to the fetus among those who received the vaccine.
Existing studies analyze antibodies to the spike protein (anti-S IgG) only, which may be present after natural infection as vaccination, and do not include antibodies to the nucleocapsid protein (anti-N IgG), which is present only after natural infection .
Among the 36 samples collected, all had high levels of anti-S IgG. Of those samples, 31 were tested for anti-N IgG and were negative.
“High levels of transplacental antibody transmission are not surprising. It’s consistent with what we see with other immunizations, “Lighter said.
“Our findings add to a growing list of important reasons why women should be advised to receive the COVID-19 vaccine during pregnancy for the added benefit of their newborn receiving crucial protection,” he said.
The researchers stress that more research is needed to determine how effective the baby’s antibodies are, how long protection will last, and if vaccination in the second half of pregnancy can result in higher levels of antibody transmission than vaccination earlier in ‘ e pregnancy. PTI