“We have a huge burden here of chronic illness that we weren’t planning on as part of a pandemic,” Collins said at a virtual event sponsored by Bloomberg Philanthropies on Thursday. 

With most respiratory viruses, people get sick for a week or two. But with the SARS-Cov-2, nearly 30% of people infected get long COVID, according to a U.K. study from February. Why that happens is a “surprising aspect” of the disease, Collins told Kelly Henning, who leads the philanthropy’s public health program.

To understand the phenomenon better, the NIH will be studying a cohort of over 30,000 COVID-19 survivors, half of whom have long COVID and the other half who had acute symptoms, Collins said. 

The NIH director added that recent data suggest that vaccinated people who have a breakthrough case can still get long COVID but that the likelihood is substantially lower.

Collins also discussed vaccine hesitancy, calling it a serious obstacle to ending the pandemic. He also touched on vaccination for kids and the possible rise of other variants.

“We sure need to be watching, surveillance, not just in the U.S. but across the world,” Collins said about the possibility of other mutations. While there was concern about the Mu variant, first identified in Colombia in January, there are fewer cases of it now in the U.S. than there were a month ago, he said.

The meeting took place as a group of outside advisers to the Centers for Disease Control and Prevention was meeting to discuss booster shots.

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