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Ask Dr. Nandi: If you're sick, how long are you contagious for?

Flu sick
Posted at 5:47 PM, Oct 23, 2023
and last updated 2023-10-23 17:47:25-04

(WXYZ) — In today’s Health Alert, as the cooler weather settles in, many people are experiencing cold-like symptoms. Whether it's COVID-19, the flu, or RSV, people are wondering when they can safely interact with others.

It's a question I hear often from my patients, and I wish there were a simple answer. Unfortunately, you can't rely solely on symptoms because you can be contagious before they appear. And some people can also remain contagious for weeks after symptoms are gone. However, I can share general guidelines.

Let’s start with COVID-19. The peak contagious period is roughly 48 hours before symptoms appear and the first five days afterward. However, we know that some people can be asymptomatic and still spread the virus.

With influenza, transmitting it before symptoms start is less common but not impossible. The peak infectious period is three to four days after symptoms develop. But some adults might remain contagious for up to five to seven days. And those with weakened immune systems could potentially spread the flu virus for much longer.

With RSV, it has a somewhat longer contagious phase, lasting three to eight days after symptoms start. However, infants and those with weakened immune systems could spread RSV for up to four weeks after symptoms resolve.

And last but not least is the common cold. With more than 200 identified viruses, the infectiousness period depends on the specific virus and the person's health. Generally, though, the peak contagious period is within three to five days after symptoms start. And once again, some individuals may remain contagious after infection, up to two weeks with a cold.

It’s tough to dodge infections when you live in the same house. And if you’re a parent with young children like myself, it can be even more challenging as kids tend to pick up, on average, six viral infections a year.

But here’s the thing. If everyone in the house is generally healthy, then you don’t have to go to great lengths to isolate someone with cold-like symptoms. But if there’s an elderly person in the house or someone with a serious medical condition, it's best to separate them from whoever is sick for at least a week after symptoms start.

As for prevention, frequent handwashing or using hand sanitizer is key. Also, stay current on vaccines, including the updated COVID-19 vaccine, the flu shot, and the new RSV vaccine for those 60 and older. These vaccines reduce the risk of severe illness and lower your chances of getting infected.