The best time to take a COVID-19 rapid test is right before you see vulnerable people or a large group, disease experts said.

The CDC recommends people with COVID-19 symptoms isolate at home for at least five days, regardless of whether they've taken a test.

Omicron exacerbates other medical conditions and there's "so much of it," Dr. Craig Spencer, ER doctor in New York City, said.

Headache, fatigue, runny nose, sore throat and sneezing are the top five COVID-19 symptoms reported by about 850,000 weekly users on Zoe app.

Just one of the 43 Omicron patients identified in the US has been hospitalized, and was discharged after two days, a CDC report says.

Trying to self-diagnose a cold, rather than COVID-19, is a "sure fire way to send COVID-19 case rates soaring again," one expert said.

After a third shot of Pfizer's vaccine, injection-site pain is most common side effect, followed by fatigue and headache.

Fully vaccinated people are more likely to report loss of smell. Unvaccinated people are more likely to report fevers.

Two young people who were vaccinated and got mild COVID-19 breakthrough cases described to Insider how their symptoms progressed.

A single dose of Pfizer's or AstraZeneca's vaccines - both of which require two shots - was either weakly or not at all effective against Delta.

Researchers said up to 2 million people in England had COVID-19 symptoms lasting more than 12 weeks - double other estimates.

Doctors in India are seeing COVID-19 patients with symptoms like hearing loss and gangrene, as the infectious Delta variant spreads.

Because there are no formal guidelines for diagnosing long COVID, doctors depend on patients to spot the signs and describe all their symptoms.

Pregnancy can have some subtle signs and symptoms. Here are some of the surprising things that could indicate a baby is on the way.

A horizontal line across nails (called a Beau's line) can be a sign of other infections too. In the future, it could be used as a COVID antibody test.

Insider reporter Kelsie Sandoval, who lost her sense of smell as a COVID-19 side-effect, is constantly asking herself: "Do my armpits smell?"

Her symptoms disappeared 36 hours after her second shot, she told the Washington Post. Scientists don't have a clear explanation for this.