BY KATHY KATELLA 
DECEMBER 1, 2020

COVID-19 upended daily life in the United States this year as SARS-CoV-2, the virus spreading the disease, swept across the country. The U.S. declared a national emergency in March, and Americans adjusted to strict guidelines, cancelled activities and closures, and mandates to stay home. As winter approaches, the virus is surging again, and the conversation continues about how to contain it.

Researchers have made progress toward vaccines to prevent COVID-19. But the timing of when those vaccines will be approved and people can start to be vaccinated is still not clear. “Until an effective vaccine against COVID-19 is available, we have to continue to do the hard, albeit tedious, work of keeping ourselves safe and healthy—by wearing facial coverings, keeping our social distance, practicing good hand hygiene, and staying home when we’re sick,” says Jaimie Meyer, MD, MS, a Yale Medicine infectious disease specialist.

SARS-CoV-2 is a virus that scientists haven’t seen before. Like other viruses, it is believed to have started in animals and spread to humans. Animal-to-person spread was suspected after the initial outbreak in December 2019 among people who had a link to a large seafood and live animal market in Wuhan, China. By January of this year, clusters of cases of a mysterious pneumonia were being reported in Wuhan, and in the following weeks person-to-person spread of the virus was reported around the world. In early March, the World Health Organization (WHO) declared COVID-19 a pandemic—a disease outbreak occurring over a wide geographic area and affecting an exceptionally high proportion of the population.

Scientists and public health officials are working as quickly as possible to find answers to key questions about how the disease affects the body and why some cases are more severe than others while they continue to investigate solutions.