How To Tell If You’re Still Contagious After Being Sick

Getting sick leading up to the holidays brings its own set of headaches. If you’re anything like me, you’ll be worried about transmitting your illness to your loved ones for fear of ruining their festive season. It’s a time of gatherings with friends and family ― people generally want to spend it in good health.

When I fall ill and start getting dreaded symptoms, I spend a lot of time researching exactly when I will be recovered enough to catch up with my friends and family again. In other words, when will I stop being contagious? How convenient it would be, I’ve often thought, if there were a “cheat sheet” of this information for the most common winter infections.

If you’ve recently gotten ill and are wishing for the same guidance, keep reading. The advice below will help you gauge whether you’re still contagious, and give you tips on how to protect the people around you from catching the sickness too.

When people contract the flu, they “get sick fairly quickly. They feel fine in the morning, and by afternoon they’re suddenly pretty sick,” said Dr. Marlene Millen, a board-certified internal medicine doctor and primary care physician at UC San Diego Health.

They’ll be hit with a few or all of the following symptoms: chills, fever, cough, sore throat, body aches, fatigue and headaches, and runny or congested nose.

Once you get flu symptoms, “people are most contagious the first few days of it,” Millen said, and remain contagious for up to seven days.

Stay home while you are symptomatic. Once symptoms start improving overall and the fever has left without the use of fever-reducing drugs — both things must be true for at least a full 24 hours — you are less contagious and can leave your home. Symptoms are considered to be improving if you’re feeling well enough to perform your daily activities.

For at least five days afterward or while you have lingering symptoms, wear a mask and practice physical distancing as much as you can.

“You can be contagious for up to two weeks afterwards, if you’re still pretty sick or if you’re immunosuppressed,” Millen explained.

The influenza diagnostic test cannot tell you how contagious a person is, said Dr. Tara Vijayan, medical director of the Adult Antimicrobial Stewardship program at UCLA Health.

COVID is caused by the virus more clinically known as SARS-CoV-2. You may have a fever, cough, sore throat, muscle aches, headache, congestion or runny nose, diarrhea, fatigue, and nausea or vomiting. Losing your sense of taste or smell is another symptom observed in COVID, although that tends to be less common now.

If you are symptomatic, stay at home even if your symptoms are mild, Millen said. Once symptoms start improving overall and your fever has subsided without fever-reducing drugs — again, both things must be true for at least a full 24 hours — you are considered less contagious, and can leave your home. Wear a mask and practice physical distancing if there are lingering symptoms or if you continue to yield a positive result on a home COVID test, both experts said.

Sometimes, COVID symptoms worsen one to two weeks after their initial onset. If this happens, stay home again and follow the above protocols to avoid spreading the virus to others.

There are people who are asymptomatic even though they have COVID. If you fall into this camp and get a positive COVID test result, wear a mask and practice physical distancing around other people for at least five days.

The common cold is caused by many different types of respiratory viruses. Typical symptoms include a runny or congested nose, coughing, sneezing, sore throat, fever, body aches and headache. It’s similar to the flu, but one way to differentiate it is that “colds come on gradually, usually over the course of a few days,” said Millen. Flu, on the other hand, is very abrupt and intense.

After you begin exhibiting symptoms of the common cold, you are contagious for about seven days, Vijayan said. Once symptoms are cleared, you are no longer contagious.

While you are symptomatic, stay home. Once symptoms start improving overall and your fever has subsided without taking fever-reducing drugs for at least a full 24 hours, you are less contagious and can return to daily activities. Masking and physical distancing are strongly encouraged until symptoms are healed or for at least five days, to prevent spreading the virus to others.

RSV, or respiratory syncytial virus, is a viral infection. “I call it the wheezing virus because it makes people wheeze,” Millen said.

If you are coughing, sneezing or wheezing, or you have a fever or a runny or congested nose, there is a chance it may be RSV. Symptoms tend to pop up in stages instead of all at once.

Once you start showing RSV symptoms, you are contagious for up to eight days afterward, according to the Centers for Disease Control and Prevention.

You are advised to stay home while you are symptomatic. Once symptoms start improving overall and your fever has subsided without fever-reducing drugs for at least a full 24 hours, you are less contagious and can cease isolation. While you have ongoing symptoms, or for at least five days, practice physical distancing and mask when you’re out and about.

If you are immunocompromised, you can be contagious for four or more weeks after you start developing RSV symptoms. This is true even if you no longer have symptoms.

Strep throat is a bacterial infection that commonly presents as a sore throat without any nasal symptoms or watery eyes, Millen explained. Your throat may also feel swollen, there may be red spots on the roof of your mouth or white spots on your throat, and you may develop a fever.

When you start getting the symptoms of strep throat, inform your doctor so they can prescribe you antibiotics for it.

“Once you start the antibiotics for strep throat, you’re only infectious for about 24 hours afterwards,” Millen said. Stay at home for 24 hours from when you start taking the antibiotics, and until your fever has lifted. Besides reducing your contagiousness, the antibiotics help ease your sore throat quickly, Vijayan noted.

Strep throat “can be contagious for up to three weeks if you don’t get antibiotics,” Millen said.

Whooping cough, or pertussis, is a bacterial infection with symptoms that mimic those of the common cold in the early stage of the disease, according to Millen. You might have a runny or congested nose, a very mild cough, and low-grade fever.

About seven to 14 days in, the coughs worsen into violent and uncontrollable coughing fits. During and after these fits, some people are short of breath or exhausted; they may vomit, or feel like they’re going to; and they may let out the characteristic “whoop” sound after the cough, according to both Vijayan and Millen.

According to the CDC, pertussis is contagious from the time symptoms begin until about 14 days after the onset of the cough.

If you have symptoms that resemble the common cold, it’s a good idea to stay home and pay attention to whether your cough worsens over time. If it does, see your doctor immediately to confirm whether you have pertussis or another illness. The antibiotic for pertussis is more effective if prescribed early.

After taking the antibiotic for pertussis for five full days, you are considered to no longer be contagious.