..

Excerpts from:

How common is it for people to contract and fight off viruses without knowing it?

In general, having an infection without any symptoms is common.

My colleagues and I have found that many infections are fought off by the body without the person even knowing it.

For the most part, symptoms are actually a side effect of fighting off an infection. It takes a little time for the immune system to rally that defense, so some cases are more aptly considered presymptomatic rather than asymptomatic.

How can someone spread coronavirus if they aren’t coughing and sneezing?

Everyone is on guard against the droplets that spray out from a coronavirus patient’s cough or sneeze. They’re a big reason public health officials have suggested everyone should wear masks.

But the virus also spreads through normal exhalations that can carry tiny droplets containing the virus. A regular breath may spread the virus several feet or more.

Spread could also come from fomites—surfaces, such as a doorknob or a grocery cart handle, that are contaminated with the coronavirus by an infected person’s touch.

What’s known about how contagious an asymptomatic person might be?

No matter what, if you’ve been exposed to someone with COVID-19, you should self-quarantine for the entire 14-day incubation period. Even if you feel fine, you’re still at risk of spreading the coronavirus to others.

After an asymptomatic infection, would someone still have antibodies against SARS-CoV-2 in their blood?

Most people are developing antibodies after recovery from COVID-19, likely even those without symptoms. It is a reasonable assumption, from what scientists know about other coronaviruses, that those antibodies will offer some measure of protection from reinfection. But nothing is known for sure yet.

How widespread is asymptomatic COVID-19 infection?

No one knows for sure, and for the moment lots of the evidence is anecdotal.

Asymptomatic SARS-CoV-2 infection appears to be common—and will continue to complicate efforts to get the pandemic under control.

https://medicalxpress.com/news/2020-05-infected-coronavirus-symptoms-physician-asymptomatic.html

..