CDC summer COVID-19 study raises holiday worries

Young to old transmission could make gatherings risky

BOSTON — Thanksgiving is six weeks away, but a Centers for Disease Control and Prevention study of spring and summer Covid-19 transmission patterns might give some families pause as they plan holiday get-togethers.

“The challenging data that’s now come out from the CDC is that we see that ages 18-24 are really the greatest risk factors for getting infected and then giving it to older people,” said Katherine Gergen Barnett, MD, Program Director in the Department of Family Medicine at Boston Medical Center. “The most important thing we can be doing right now is really focusing on those young people and how to make sure that they’re low risk.”

The CDC study looked at hundreds of Covid 'hotspots '-- that is, places in which more than 100 infections occurred in a given week. It found, in general, that infections in younger people peaked around the time the hotspot was identified -- but infections in older people continued to rise for weeks after.

The suggestion is that the young, in effect, established the hotspots -- then their infections spread to older members of the community.

Though the data is from the warmer months, it has troubling implications as we head into the colder ones, said George Abrahan, MD, Chief of Medicine at Saint Vincent Hospital in Worcester.

“Unfortunately this is something we had sort of anticipated and feared,” Abraham said. “We have seen a surge in cases probably because of a combination of factors. One, the younger folks being either asymptomatic carriers or having very mild infection, but are still infectious. And two, as the weather turns colder people are less outdoors and more indoors which means there’s more prolonged exposure to someone who might be potentially infected.”

Looking to the holidays, Abraham doesn’t see how families carry on as normal.

“We are extremely concerned that parents and grandparents or other family members who may not be protected by virtue of either having had disease or because there is no vaccine available right now are potentially vulnerable,” he said. “The in-person, unmasked eating together is the classic set up for spread of infection.”

The problem, of course, is that Covid virulence can differ dramatically with age.

“The chances that an older person will either get hospitalized or die of Covid 19 are dramatically higher than young people,” said Robert Finberg, MD, professor and Chair of Medicine at UMass Memorial Medical Center. “And many young people are asymptomatic.”

So unless those young people get tested just before coming home for the holidays they might never know if they are harboring the potentially harmful virus.

“I think as families are starting to think about ‘what does November look like’, obviously we need a lot more data to see what’s happening here in Massachusetts and other states closer to the time,” Barnett said. “But we are going to need a lot more testing. Certainly, regular Thanksgiving will likely be off the table, sadly, this year.”

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