Published in JAMA, University of Minnesota Medical School researchers have discovered the number of babies born in Minnesota with cytomegalovirus (CMV) decreased significantly during the COVID-19 pandemic. The study found that in the five-year period leading up to the pandemic, about one baby in every 200 births was born with CMV. Between August 2020 and December 2021, the number decreased to one baby in every 1,000 births.

"At last, something positive came out of the COVID-19 pandemic," said Dr. Mark Schleiss, principal investigator of the study and a pediatric infectious disease specialist and professor in the U of M Medical School. "The hygienic precautions we all have engaged in during the pandemic—masking, hand-washing and infection prevention behaviors—were almost certainly responsible for the reduction in CMV transmission, which in turn protected mothers and newborns from the potentially devastating effects of the CMV virus."

CMV is the most common virus that causes birth defects and disabilities in newborns.

Researchers concluded that the combination of strict hygienic precautions, stay-at-home practices, and most importantly, the closure of child care and group day care centers all resulted in reduced transmission of the CMV virus to children and their mothers during the pandemic. Women with toddlers in group day care are at risk for acquiring it from their child. If such infections occur during a subsequent pregnancy, the next child may be born with the infection and be at risk for developing disabilities, especially hearing loss.

The research team recommends further public awareness campaigns to increase knowledge and awareness of CMV. Dr. Schleiss was a part of the advocacy campaign that led to the Minnesota legislature's passage of the Vivian Act in 2021. Led by Minnesota parents and doctors, the law made Minnesota the first state to start universal screening for congenital cytomegalovirus in all newborn infants. The law aims to enhance knowledge and enable strategies for prevention of CMV infection.