Doctors and researchers are scrambling to better understand the basics of COVID-19 (the disease caused by the coronavirus), including how it is transmitted, how it affects the body, and when a vaccine might be available.
Some of the biggest questions right now are around its transmission: How long are people contagious? And is it possible to get COVID-19 twice?
Here’s what we know so far.
People may be contagious for a few weeks, and it peaks at a certain point.
According to the Centers for Disease Control and Prevention, “people are thought to be most contagious when they are most symptomatic (the sickest).”
Beyond that, however, the CDC does not have much official guidance about the period of infectiousness for COVID-19 — or about the onset or duration of “viral shedding.” That term refers to the stretch of time during which a person infected with a virus emits it from their body via secretions which, in the case of COVID-19, pretty much means when they are coughing and sneezing it out. A very small recent study suggested that people may emit high amounts of the virus before they show any symptoms, STAT News reported, but that research has not been peer reviewed.
The bottom line?
“The answer — today — is that people appear to be contagious one to two days prior to getting sick, and for one to two weeks after getting sick,” said Dr. Stephen Gluckman, an infectious diseases physician at Penn Medicine and the medical director of Penn Global Medicine. (This timeframe generally goes for any contagious illness, not just COVID-19.)
“As we improve, the amount of virus we’re shedding into the environment drops off,” Gluckman said.
It’s unclear whether reinfection is possible.
Often, when the body is infected by a particular virus, it develops protective antibodies that help prevent repeat infection. That is how, for example, flu vaccination works.
Pediatrician Dr. Peter Jung weighed in on the possibility of reinfection in children: “No one knows for sure, but most children likely develop at least short-term immunity to the specific coronavirus that causes COVID-19,” he said. “But just as the flu can mutate, so could COVID-19, which would make an individual susceptible to reacquiring the infection.”
Other experts feel it is far more likely that once an individual has contracted COVID-19, they will not be able to get it again.
“Coronaviruses aren’t new, they’ve been around for a long, long time and many species — not just humans — get them. So we know a fair amount about coronaviruses in general,” Gluckman said. “For the most part, the feeling is once you’ve had a specific coronavirus, you are immune. We don’t have enough data to say that with this coronavirus, but it is likely.”
But in the present moment, basically no one has any antibodies that might eventually protect against infection or reinfection. Because COVID-19 is so new, there is “essentially no immunity against this virus in the population,” Dr. Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases, said in a recent media briefing.
Prevention continues to be the best defense.
Wash your hands often. Avoid close contact with sick people. Put distance between yourself and other people if COVID-19 is spreading in your community, the CDC has recommended.
And finally, stay informed. Despite the fact that there is much experts do not understand about the virus right now, they are learning more every single day.
“Panicking doesn’t get you anywhere,” Gluckman said. “But this isn’t simply going away. It’s out of the bag.”