Coronavirus
The coronavirus is most infectious before people even know they have it, UW virologist says
Can you get COVID-19 more than once? Is it safe to go back to restaurants? How effective are masks? Should you get the antibody test?
The News Tribune put those questions and others to Dr. Keith Jerome. He heads the University of Washington’s virology division and is a member of the vaccine and infectious disease division at Fred Hutchinson Cancer Research Center.
As with other experts battling the COVID-19 pandemic, Jerome is quick to admit there many questions he can’t answer.
“There’s so much we don’t know,” Jerome said in an interview this month. “We’ve only known about this virus for five months.”
Still, Jerome is buoyed by the progress science and medicine have made.
“It’s really remarkable, what we’ve learned in a short amount of time,” he said.
Can you get COVID-19 more than once?
Is the current coronavirus, called SARS-CoV-2, a repeat offender? The key to understanding that, Jerome said, lies in understanding what role antibodies play.
Antibodies are produced by the body in response to a virus, among other things. Normally, they offer protection should a virus come calling again, sometimes for life.
“One thing we still don’t know, for any given person, if we tell them they have those antibodies, what does it mean,” he said. “Does it mean they’re completely protected?”
Jerome has a hypothesis that having the antibodies will offer some protection.
“It will probably keep you from getting as sick as you might have otherwise,” he said. “But, it probably won’t be complete protection.”
Known coronaviruses don’t sicken people as severely as SARS-CoV-2 does. However, researchers know that a coronavirus infection offers some protection against reinfection that probably lasts about two years, Jerome said.
“After that, you’re close to where you were before,” he said.
UW researchers will be measuring the amount of antibodies in people who were exposed to COVID-19.
“Best case is that we see that amount of antibody stays stable,” Jerome said. “Then we’ll say, ‘You’re probably still protected.’”
With some viruses, a diminished level of antibodies doesn’t mean protection is lost.
“There are still small amounts (of antibodies) and the (white blood) cells are ready to make that antibody very quickly,” he said.
The answers will be revealed in the coming months and years, Jerome said.
“We’re all impatient. We want to know everything now. But for this, we’re going to have to wait,” he said.
Transmission and mask wearing
When is SARS-CoV-2 most likely to be passed from one person to another? Before you even know you have it, Jerome said.
“If we get this virus, we’re actually most infectious before we actually feel very sick,” Jerome said. “That’s when we’re spreading the virus.”
That’s why wearing a mask in public is key in reducing the chances the virus will be passed between individuals, he said.
“It’s not like I wear a mask because I’m living in fear for my own health,” Jerome said. “I am wearing a mask because, in case I do have it, I don’t want to give it to another person.”
How many SARS-CoV-2 viruses does it take to start an infection in a person? How many viruses does a person breathe out when they are infectious? Those questions still has no definitive answers, Jerome said.
“You’ll get a lot of opinions on this,” he said. “Your likelihood of getting infected is almost a roll of the dice. But the number of dice you get, and how many times you get to roll them, is determined by your circumstances.”
An uninfected person who walks into a cloud of viruses that an infected person just coughed out in a grocery store has a high chance of getting infected.
But an uninfected person who has dinner with a friend who is infected, but showing no symptoms, also has a high chance of getting infected.
“If you sit around the dinner table all night, even if people aren’t coughing, that little bit of virus coming out over time starts to become a larger and larger virus threat,” Jerome said. “You don’t get infected by one viral particle.”
For some viruses, it takes thousands, and in some cases, millions of viral particles for infection to occur, he said. But with some viruses, like the Norovirus that plagues cruise ships, it takes very few to cause an infection.
“We don’t know where COVID-19 falls on that spectrum,” he said.
How important is cleaning surfaces to stop the spread of the virus?
Video clips and photos from China to Russia show teams of workers spraying streets and other large surfaces in an attempt to sanitize large areas. The practice hasn’t been popular in the U.S.
“In terms of spraying viracide up and down the street, I’m not sure you’re saving many cases at all,” Jerome said.
Nevertheless, every effort helps, he said, and cleaning high touch areas is a good idea in settings used by multiple people.
“We clean door knobs frequently,” he said. “Actually, we try not to touch them. We know the virus can live, sometimes for a couple of days, on metal surfaces.”
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