INDIANAPOLIS (WISH) — Viruses tend to spread more easily in colder weather due to less humidity. There are a billion cases of the flu every year. According to the American Lung Association, adults get two to four colds a year, and right now, there are over 700 million COVID-19 cases around the world. A lot of people are concerned about how contagious they are once they feel better. When can they get back to their regular schedules?

With flu and cold season underway and the persistent threat of COVID-19, many people recovering from these illnesses worry about how long they can infect their family and friends. Health experts advise that the duration of contagiousness varies depending on the specific illness.

For the flu and common cold, individuals are generally contagious for the first few days of illness. However, it’s essential to note that some symptoms, like a lingering cough, may persist even after the person is no longer contagious.

“Some people have the chronic fatigue, sometimes, persistent fevers, other people have more chest issues,” said Dr. Dixie Harris, a Pulmonary Critical Care Physician at Intermountain Health.

For COVID-19, people are typically contagious for a period before symptoms appear and up to five days after the onset of symptoms. However, this can vary, and the Centers for Disease Control and Prevention recently changed its longstanding guidance, saying that people can return to work or regular activities if their symptoms are mild and improving and it’s been a day since they’ve had a fever.

Though the virus has not become less contagious, this new protocol may allow people who have been unable or unwilling to stay at home for five days a shorter isolation period enabling them to take at least some precautions when sick.

“They think they’re getting better, and then, they try to do something, and then they have to sit for six hours, or two days,” Harris said. “So, it’s just one of these situations where they have to really pace their activities.”

Also, for strep throat, doctors say you are no longer contagious after 24 hours of antibiotics.

For the stomach flu, you are no longer contagious two days after the symptoms pass.

And for whooping cough, you are no longer contagious after five days of antibiotics.

This story was created from a script aired on WISH-TV. Health Spotlight is presented by Community Health Network.