There's evidence that reinfection is unlikely for at least three months even for people who had a mild case of COVID-19.
The best known example: Researchers in Hong Kong said a man had mild COVID-19 and then months later was infected again but showed no symptoms.
His second infection was detected through airport testing, and researchers said genetic tests revealed slightly different strains of the virus.
It's not known whether people who've been reinfected but show no symptoms would be able to spread the virus to others.
That's why health authorities say even people who have recovered from COVID-19 need to wear a mask, keep their distance and practice good hygiene.
The AP is answering your questions about the coronavirus in this series.
This transmission electron microscope image shows SARS-CoV-2, the virus that causes COVID-19, isolated from a patient in the U.S., emerging from the surface of cells cultured in the lab.
There's some evidence that a specific mutation called D614G may have made it easier for the virus to be transmitted between people.
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Studies on the new coronavirus and other germs show wearing a mask helps stop infected people from spreading disease to others.
Evidence also suggests that masks may offer some protection for the people wearing them.
The virus spreads from droplets people spray when they cough, sneeze or talk.
While some droplets may still spread out, wearing a mask could reduce the amount, providing a benefit to others.
Research shows people don't get as sick when exposed to smaller amounts of virus, said Dr.
And masks may protect the people wearing them by reducing the amount of droplets from others that might make contact with them.
food processing plants where masks were required and infection clusters occurred, Gandhi noted that most workers who developed COVID-19 had mild illness or no symptoms.
Research on a different coronavirus has also found low infection rates among people who frequently wore masks in public.
Experts say masks are particularly important with the new coronavirus because infected people can be contagious even if they don't have symptoms.
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Health officials don't recommend the clear plastic barriers as a substitute for masks because of the lack of research on whether they keep an infected person from spreading viral droplets to others.
Two diagnose whether you have an active infection, and a third indicates if you previously had the virus.
This is considered the most accurate way to diagnose an infection, but it's not perfect: The swab has to get a good enough sample so any virus can be detected.
A newer type of test looks for proteins found on the surface of the coronavirus, rather than the virus itself.
Scientists don't yet know if antibodies protect people from another infection, or how long that protection might last.
Whether students have to wear masks, and the trouble they could face if they don't, depends on where they go to school.
South Carolina says students have to wear masks in the hallways, but can take them off in the classroom if a teacher allows it.
In the northern Italian town of Codogno that was hit hard by the virus, elementary and middle school students have to wear masks.
In New York City, officials say students will simply be sent home and told to attend school remotely if they refuse to wear masks.
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Both the flu and coronavirus spread through droplets from the nose and mouth.
Both can spread before people know they are sick.
The flu has a shorter incubation period — meaning after infection it can take one to four days to feel sick — compared to the coronavirus, which can take two to 14 days from infection to symptoms.
But many people with COVID-19 don't spread the virus to anyone, while a few people spread it to many others.
Precautions against COVID-19 — masks, social distancing, hand-washing — also slow the spread of the flu, so health officials hope continued vigilance could lessen the severity of this year's flu season.
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It appears the virus can spread among children and teens, but how easily may vary by age.
Children generally don't appear to get sick or experience symptoms as often as adults when they're infected.
That might help explain why they appear less likely to spread the virus — they're less likely to be coughing and sneezing.
Some of the latest evidence comes from a recent report that showed infected children in Utah day care centers and day camps spread the virus to family members, including siblings.
That suggested very young children with no symptoms or very mild ones can spread infection, but that the rate of spread was low.
A large study from South Korea suggested that kids aged 10 and up may spread the virus more easily to family members than younger kids, and might even spread it as easily as adults.
We're still learning, but it seems that much of the spread of the coronavirus has been caused by what disease trackers call superspreader events.
Disease trackers discovered that bands played at all four bars, so musicians may have spread the virus to more than 100 people all told.
Scientists studying three months of contact tracing data from Hong Kong estimated that 19% of people infected were responsible for 80% of the spread of coronavirus infections.
The timing of the event and the number of people infected suggests the possibility of superspreading, she said.
Health officials and medical groups are urging people to get either the flu shot or nasal spray, so that doctors and hospitals don't face the extra strain of having to treat influenza in the midst of the coronavirus pandemic.
Not to mention the confusion factor: The illnesses have such similar early symptoms that people who get the flu may mistakenly think they have COVID-19, said Dr.
Joe Biden's campaign said Thursday that vice presidential nominee Kamala Harris will suspend in-person events until Monday after two people associated with the campaign tested positive for coronavirus
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