As seasonal virus activity surges across the United States, experts stress the importance of preventive measures – such as masking and vaccination – and the value of treatment for those who do get sick.

Tens of thousands of people have been admitted to hospitals for respiratory illness each week this season. During the week ending December 23, there were more than 29,000 patients admitted with Covid-19, about 15,000 admitted with the flu and thousands more with respiratory syncytial virus, or RSV, according to data from the US Centers for Disease Control and Prevention.