7 things we know about the virus

Clarity and consensus emerging as scientists learn more in battle against microscopic foe

Months into a global pandemic, scientists and infectious disease doctors know more about COVID19, the disease caused by a new coronavirus, than they did when it began.

Here are some things research has taught the medical community that may not have been clear from the get-go:

The virus spreads through the air

The coronavirus is efficient at spreading because it can be transmitted just by an infected person breathing and talking somewhat close to others.

Mounting scientific evidence has shown the virus can travel through airborne droplets that form when a person with COVID-19 coughs, sneezes, sings, talks or breathes. That fine mist containing particles of the virus can remain suspended in the air for some time.

Indoor spaces without good ventilation are riskier environments for catching the virus. And that’s also why the public has been instructed to keep a distance of at least 6 feet from others who are not in their household.

Despite the fact that the air seems to be the most common way the virus spreads, public health experts still urge everyone to wash their hands frequently. Those droplets can land on surfaces and be transferred by touch if uninfected people also make contact with their mouths, noses and eyes.

Masks help other people

The U.S. population got a bit of mixed-messaging on this subject in the beginning of the crisis, but the consensus today is masks work and

are an important part of stemming transmission.

Some public health experts didn’t initially encourage their use. They were concerned a run on masks would leave health care workers without adequate equipment.

U.S. Centers for Disease Control and Prevention Director Robert Redfield said healthy people should not wear masks when he testified before a congressional subcommittee in February. Shortly thereafter, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told a Senate committee people didn’t need to wear masks because the disease wasn’t widespread.

Masks are effective because they can prevent people who have the virus but don’t know it from infecting others. The masks trap respiratory droplets from infected people from traveling into the air.

Food isn’t a likely source

There may have been a time when people feared their food could be a culprit, but the risk of getting sick from eating or handling food is thought to be low. (See again “The virus spreads mostly through the air.”)

No cases of COVID-19 have been traced back to touching food, food packaging or shopping bags so far.

Public health experts continue to recommend that people wash their hands after shopping and handling food packages because of the low chance that airborne infected respiratory droplets have settled on a surface they’ve touched.

You probably don’t need a negative test to come out of isolation

Early in the pandemic, the gold standard was for a previously infected person to get a negative coronavirus test before reentering society or going back to work.

Epidemiologists have since learned patients can continue to test positive for COVID-19 long after they’re contagious because of bits of inactive virus fragments that remain.

Now public health experts are urging people to follow a time- or symptom-based strategy for determining how long to stay in isolation. Research shows a person’s contagious period could range from one to two days before the onset of symptoms to seven or eight days after. For mild cases of the coronavirus, the CDC is recommending that patients isolate for 10 days after their symptoms started.

If a person tests positive for COVID-19 but never had any symptoms, experts say that person should isolate at home for 10 days after the first positive test.

And as long as the individual has gone 24 hours without a fever and hasn’t used fever-reducing medications, he or she is usually free to go.

Early comparisons to the flu were misleading

Many medical experts underestimated the dangers of COVID-19 and made false equivalencies to the flu.

The World Health Organization estimates 290,000 to 650,000 people die of flu-related causes every year. In less than a year, there have been about 1.36 million deaths from the coronavirus worldwide, according to Johns Hopkins University.

Children can get sick and spread the virus

While severe illnesses are rare among children and adolescents, they can still get the coronavirus. And medical experts learned a few months into the pandemic that some are at risk of a rare complication, called multisystem inflammatory syndrome in children, or MIS-C.

The syndrome, which seems to happen a few weeks after a child’s infection, affects various parts of the body and may cause problems with the heart and other vital organs. Globally, a small number of children and adolescents with the condition have died.

Physicians have reported patients with a fever lasting several days and symptoms such as irritability, abdominal pain, diarrhea, vomiting, rash, conjunctivitis, lack of appetite, red or cracked lips, red or bumpy tongue or swollen hands and feet. Some have likened it to other hyperinflammatory conditions, such as Kawasaki disease and toxic shock syndrome.

Even with mild cases of COVID19, children can spread it to others. Like adults, young patients can also get the virus but show no symptoms and become unsuspecting spreaders.

There’s a working definition for someone who may have been exposed

A so-called “close contact” is someone who was within 6 feet of an infected person for a total of 15 minutes.

That definition has slightly changed, as many public health experts were once thinking of that exposure time as 15 consecutive minutes, rather than cumulative, in a 24-hour period.

Exposure could happen anywhere from two days before the infected person notices signs of his or her illness to 10 days after the onset.

The CDC says a person can still be considered a close contact, even if that individual wore a mask around the infected person.