It’s easy to forget that just a few months ago, the virus that is causing the Covid-19 pandemic around the world was not known, at all, to science.

In the months and weeks since, researchers have been learning as much as they can about this pathogen — and at breakneck speed. Scientists have sequenced its genome and begun to create vaccines in the hope of making people immune to it. They’ve also learned, critically, that people can pass the virus on to others before they get symptoms themselves. That makes the virus hard to contain. But it also makes it clear that severe actions — like the social distancing measures in place in the US and around the world — are necessary in the fight to save lives.

We still don’t know how this pandemic will play out. That’s in large part because there are crucial unanswered questions about this virus and the disease it causes. For example, researchers don’t yet have precise estimates of how deadly the virus is or an exact understanding of how it spreads. The answers to these questions will provide key insights into stopping this pandemic in the least disruptive way possible.

Scientists warn we may need to live with social distancing for a year or more:

It may be too easy to look at these uncertainties and the lack of data and feel cavalier: Maybe this all isn’t as bad as people are saying.

Do not take comfort in these uncertainties. Take caution.

“The way we deal with the uncertainty is we have to cover all of our bases,” Peter Hotez, the dean of the National School of Tropical Medicine at Baylor College. “A year from now we’ll realize some of the things that we did may not have been necessary.” But we have to proceed with extreme vigilance due to the many unknowns of this virus and the serious risk it poses to so many around the globe.

These are the nine most important unanswered questions about Covid-19 that will help determine the course of this outbreak. Be humbled by this list. We are. And take care.

1) How, exactly, does Covid-19 spread?

The virus — known as SARS-CoV-2 — that causes Covid-19 has infected more than 222,000 people since its emergence. (Of them, at least 9,000 have died.) That’s just the confirmed cases. A great many more may have occurred (more on that later).

Why has it spread so fast? “The best explanation for this rapid spread is that the virus is being passed through droplets from coughing or sneezing,” Vox’s Julia Belluz explains. “When these virus-laden droplets from an infected person reach the nose, eyes, or mouth of another, they can transmit the disease.”

But it’s still unknown how significant other modes of transmission are in spreading the disease.

2) Can people become reinfected? And, if so, after how long?

Another huge unknown: Can people become reinfected with Covid-19 after they’ve had it? There are some reports of people in China and Japan testing positive after recovering from the infection. Though, to be clear, it’s unknown whether those people were truly reinfected or still just had low levels of the virus in their systems after they felt better.

“I would say that the biggest unknown is how potent is the immune response generated in an infected person,” Akiko Iwasaki, an immunobiologist at the Yale School of Medicine, writes in an email. “How long would [immune] protection last? ... The answers to these questions are key to understanding whether herd immunity is effective.

Media Contact: 
Allison Grey 
Journal Manager 
Journal of Clinical chemistry and Laboratory Medicne
|Email: jcclm@molecularbiol.com