Published September 16, 2024
One of the best ways to help stop the spread of illness is to avoid contact with others when you’re most contagious. Knowing when to stay home will be critical as the respiratory season ramps up.
Flu and RSV tend to peak in the winter months while rhinovirus or the common cold pops-up year-round. COVID has bucked seasonal trends and is surging now.
“Most infectious diseases, including respiratory viruses, are most contagious when symptoms peak,” said Yale New Haven Hospital Infectious Disease specialist Scott Roberts, MD, assistant professor in infectious diseases at Yale School of Medicine. “When COVID first hit, no one had immunity, and it had a weird pattern. Contagiousness peaked on the day symptoms started, and that made it challenging to combat because people were already contagious before their symptoms started.”
Immunity through vaccination and natural infection has changed that pattern. Now, COVID is behaving more like flu and RSV where contagiousness peaks when symptoms peak several days into the illness.
“A big study came out in the fall of 2023 which showed that most people are the most contagious on day four of symptoms with COVID and then it wanes from there,” said Dr. Roberts.
While people become less contagious over time, they are still contagious with COVID for an average of eight days. That may vary depending on factors including underlying health conditions and the severity of illness.
People are most likely to be contagious with flu for seven days while they may be contagious with RSV for eight days. The CDC says for all three illnesses, you no longer need to isolate if you have no fever for 24 hours and symptoms have improved. However, with COVID it’s still important to take added precautions for the next five days, including physical distancing and wearing a mask.
If you have COVID and want to be extra cautious, you can take an at-home rapid test first before interacting with others, though they are not 100% accurate.
“There are scenarios where I would take more precautions,” said Dr. Roberts. “For example, if I’m going to a Thanksgiving gathering with many vulnerable immunocompromised family members and I’m not sure if I’m still contagious, I would wear a mask.”
Household contact is one of the highest risks for being infected so, if possible, isolate as best you can when you are contagious. That means staying in a separate room, using a separate bathroom, eating meals at different times and opening windows to improve air flow.
Hand washing and masking are helpful tools too, but the best thing you can do is get vaccinated.
“For most people, getting the vaccines in the fall is a good idea. It gives people immunity before the winter when things really ramp up, but get it whenever you see it’s available,” said Dr. Roberts. “It is safe to get the flu and COVID shot at the same time. Now there’s also a new RSV vaccine for people at risk.”
Those who should consider getting an RSV vaccine includes those 75 and older or those 60 and older who are at increased risk for severe illness.
Do you really need a flu and COVID shot if you got one last year? Yes, says Dr. Roberts. The updated vaccines are tailored to combat strains currently circulating to help protect against severe illness and hospitalization.
