By Imogen Howse via SWNS
Babies born to mums who had COVID-19 whilst pregnant are three times more likely to develop respiratory disease.
However, if a mother had been vaccinated prior to infection, the risk to their newborn is significantly reduced.
Researchers from the University of California (UCLA) analyzed 221 mothers, most of whom developed COVID-19 whilst they were pregnant.
In total, 68 percent of the participants had not been vaccinated.
Of these, 16 percent developed a severe or critical COVID-19 infection, compared with just four percent of women who had had their vaccination.
The team at UCLA found that nearly one-fifth (17 percent) of infants who had been exposed to COVID-19 while in the uterus developed respiratory distress after birth.
This is a very high frequency, as, without COVID-19 exposure, respiratory distress only occurs in five to six percent of babies.
Of the babies born with respiratory distress, 21 percent had mothers who had suffered a severe or critical COVID-19 infection.
Senior author Dr. Karin Nielsen, a pediatrics professor at UCLA, said: “We found unusually high rates of respiratory distress shortly after birth in the full-term babies born to mothers who had COVID-19 during pregnancy.
“The mothers had not been vaccinated prior to acquiring COVID, indicating that vaccination protects against this complication.”
The study also found that full-term babies were suffering from respiratory distress when being born after ‘in-utero’ COVID-19 exposure, despite the breathing disorder usually only affecting premature infants.
Dr. Nielsen explained: “Not only do our results show higher rates of respiratory disease in Sars-Cov-2 exposed uninfected infants when compared to the general population, but we also observed more cases of respiratory disease at later gestational stages than anticipated.
“In other words, at stages when neonates should presumably have more mature lung anatomy.”
The team's research, published in the journal Nature Communications, found that structures designed to clear mucus from the respiratory tract – called cinfantsalled motile cilia – did not function properly in infants who had been exposed to COVID-19.
The exposed babies also presented with a higher production of antibodies called immunoglobulin E, suggesting that their immune systems had been working.
According to the researchers, the study has some limitations.
These include the small sample size and the lack of data on the effects that a vaccination after infection had.
Many of the participants were also enrolled from a large tertiary and quarternary medical center, which typically receives the sickest patients.
This means the findings may be skewed towards more severe COVID-19 infections than what is typically found among the rest of the population.