Kids' birthday parties are a hotspot for COVID infection, study finds

• In counties with high rates of COVID-19, families with birthdays had a 31% risk of getting infected.
• Experts say that's because people tend to gather for birthdays.
• Unlike public events, COVID-19 spread in small gatherings have been hard to measure.

Along with a packed wedding or a busy bar, kids' birthday parties were a hotbed for COVID-19 spread in 2020, a new study finds.

Using health claims data of 2.9 million homes from January to November 2020, researchers at Harvard Medical School, the RAND Corporation, and Castlight health analyzed COVID-19 rates two weeks after a family member had a birthday.

Though children have a lower risk of developing severe COVID-19 symptoms, and of transmitting the virus, the authors found more cases related to children's parties than adults'.

The study, published in JAMA Internal Medicine, found that within counties with high rates of COVID-19, families with birthdays two weeks prior had a 31% risk of getting COVID-19 compared to families with no birthdays.

The researchers found Democrats and Republicans have behaved differently during the pandemic, but counties' political affiliations didn't change the risk of getting COVID-19.

The researchers didn't track if families hosted a birthday party, nonetheless, they presumed that people got together for a kid's birthday. And the more people at a party, the higher the risk of getting exposed to COVID-19, according to the Centers for Disease Control and Prevention.

COVID-19 spread was harder to track at small gatherings

While COVID-19 spread was easier to track at public events - like measuring COVID-19 cases and deaths - small gatherings were trickier to measure.

K.J. Seung, the chief of strategy and policy for Partners in Health's Massachusetts COVID-19 response and involved in a contact tracing system, told the New York Times that contact tracers had a hard time tracking COVID-19 spread at a social gathering, in part, because people either didn't remember or were ashamed to admit when they met someone for dinner.

"Small social gatherings are the most difficult locations to trace," Seung said. But, "when we talked to contact tracers around the country, they were like: Yeah, people are getting infected at these small gatherings."

Dr. Ashish Jha, the dean of the School of Public Health at Brown University also told the New York Times that, unlike public places, people felt safer in their homes. "There was definitely this element of your home is a safe place and therefore when you have your friends and family over in your home, it just doesn't feel risky," Jha said.

Given that kids under 12 are still not eligible for the COVID-19 vaccine, the researchers cautioned that children's parties can still be a risk.