Dangers of indoor gatherings cited

The choices people make in fall and winter — whether to meet indoors, continue to wear masks, or maintain distance — are likely going to be the biggest determinants of how serious a cold weather surge could be, according to a Princeton study released in September but not yet peer reviewed, said Rachel Baker, postdoctoral research associate at the Princeton Environmental Institute and the study’s lead author.

“Indoor gatherings are going to be higher risk,” she said, due to indoor air being more stagnant than air outside. “If we think the virus can be partly airborne then being indoors you sort of trap it.” Baker believes the newness of this virus also means seasonal changes that normally decrease viral spread are less impactful. Human immune systems have no familiarity with COVID-19, she said, which might be why summer, typically a less friendly environment for viruses, didn’t squelch the pandemic.

“Seasonal coronavirus transmission peaks pretty reliably in the northern hemisphere some time in December or January,” said Stephen Kessler, a research fellow in the department of immunology and infectious diseases at Harvard T.H. Chan School of Public Health.