I recently did a Q&A on Facebook about the COVID19 pandemic and about HCov-19/SARS-CoV-2, the virus causing it. People asked if they could share the answers, so I’ve converted some of the frequently asked questions into a blog post.

Why should I trust you?

You shouldn’t, at least not without verifying. There is a tremendous amount of misinformation about COVID19 flying around. Some of it comes from people with no credentials, but some of it comes from people who at least seem to have credentials.

There’s one fellow who’s been on the news a lot who pitches himself as a “Harvard epidemiologist”. This is technically correct, but he’s a visiting researcher at Harvard, not a Professor, and his degree is in nutritional epidemiology, not infectious disease epidemiology.

I encourage you to look around this website at my publications, CV, and other posts, and decide whether my answers are likely to be worth your time.

Is this really a big deal?

Yes, it really is. Exponential growth can be hard to grasp, and in many countries we’re only now beginning to exit the calm-before-the-storm phase. Things increase slowly at first, then rapidly. In the US and Europe, governments were slow to take actions proportionate to the level of the problem. They have started to course correct, but there is still a real risk that some or many of them could face an Italy- or Iran- style health-system overload.

But I read a Medium Post / STAT news article / NYT op-ed saying it’s overblown!

Basically, you should assume that anything posted on Medium about COVID by an amateur makes elementary mistakes unless:

  1. you are yourself an expert and can verify
  2. an expert verifies it for you

One of the frustrations of the first pandemic of the social media era is that every person with a little bit of quantitative training gets to cosplay as an epidemiologist. And that’s dangerous. Heck, a lot of what the experts are saying contains errors or oversimplifications (this post included, probably!). So don’t totally trust the experts, but don’t even waste your time deciding whether to trust any particular amateur. More likely they’ve missed something obvious than that they’ve seen something everyone else has missed. You’re better off spending your energy verifying that expert arguments pass the smell test (they might not!)

Exception that proves this rule: this viral post by an amateur is lucid and gets the science almost right (and the errors don’t change the qualitative conclusions). His follow up is also broadly correct, though there are more (non critical, but very real) errors.

But people always overreact! Remember Ebola?

In rich countries, people have been conditioned (rightly) to see “big scary virus” as media fearmongering and hypochondriacal public overreaction. And it was for, say, Ebola (at least for people in rich countries). The comparison with Ebola is in fact very instructive.

Ebola gets you really, really sick. Anyone who gets it, no matter how young and healthy, has a substantial chance of dying. This is true even if they get excellent care, though we developed some reasonably effective therapies during the 2014 outbreak. People, even in rich countries, are justifiably terrified of getting it. But Ebola’s also relatively easy for a rich country to control. The symptoms are obvious, and people only are infectious once they’re symptomatic. So by quarantining the symptomatic and carefully managing biohazardous waste, a country with sufficient resources can prevent an Ebola outbreak from taking off, particularly if it knows ahead of time (as places like the USA and UK did in 2014) that cases might be coming in, and has time to prepare. The 2014 outbreak (and this year’s) were destructive because they hit countries without that kind of public health infrastructure.

The new coronavirus (SARS-CoV-2, officially) does not get most people critically sick. Mounting evidence suggests that a substantial fraction of cases could be wholly asymptomatic (probably somewhere between 10% and 40%). In the majority of symptomatic people, the symptoms are flulike, though worse than standard seasonal flu. So people are tempted to pooh pooh it. But it is really, really hard to control, even for a rich, developed country, and especially for a poorer one. There’s strong evidence that people can transmit before they become symptomatic, and it may be that people who get infected but never become symptomatic can transmit as well. That dramatically reduces the effectiveness of quarantine. Moreover, because most people on earth have antibodies to flu, it spreads less effectively. Pretty much nobody has prior immunity to SARS-CoV-2, which means that if it’s not controlled, 20–40% of the world’s population (or more) will get sick before we can roll out a vaccine. And even if the final case fatality settles closer to 0.5% than the 3.4% (irresponsibly!) reported by the WHO, 0.5% * 20% * 7 billion people = 7 million deaths.

I can’t put it better than biologist Michael Eisen did:

Still, did my university really need to end in person instruction?

Yes, absolutely, though it’s important that they provide resources for vulnerable students who can’t just go home. US and German got the memo relatively early, but UK and other European universities were worryingly slow to follow suit.

Should I expect to be able to travel by air for the next few months?

Probably not, unfortunately.

Is the fatality rate really 3.4%?

Almost certainly not. There are a lot of mild/asymptomatic cases. I’d guess it’ll settle between 0.5% and 1.5% when all is said and done. But that said, in places where healthcare systems get overwhelmed, it could be much higher.

So it’s no big deal then?

Afraid it’s still very much a big deal. Since this is a new virus, there’s basically no “population immunity”: that is, almost nobody, as a fraction of the global population, is immune to the virus. And we won’t have a vaccine for a while. That means that 20-40% of the world’s population could easily get infected. And even at a 0.5% case-fatality rate, that’s 7 million deaths or more. And we’ll only achieve a 0.5% case fatality rate if we can prevent hospitals from getting overwhelmed.

How do we prevent hospitals from getting overwhelmed?

“Flatten the curve” – slow down transmission so that infection accumulate more slowly. There will still be quite a few, but if they’re spread out enough the healthcare system won’t reach its breaking point at any one moment in time. This graphic is helpful:

Do people who get it become immune?

Almost certainly. I have another post with a full discussion, including an immunology primer.

What about those news stories I saw about “reinfection”?

Irresponsible and misleading. All such reported cases are clearly cases of resurgent infections: the patient ceases to have symptoms and/or tests negative, then develops symptoms again or tests positive again.

These are very common for respiratory viruses. You may have even noticed your symptoms going away and then coming back again when you’ve had the common cold, which can be caused by more benign human coronaviruses!

Calling a resurgent infection a “reinfection” is simply inaccurate. True reinfection would be much scarier to observe, because it would imply that accumulation of immunity to the disease in the population could be slow or nonexistent. But for now it looks like people will become at least temporarily immune, which is very good news.

After someone has recovered and is no longer symptomatic, are they immediately safe to be around others?

At this point I would advise people who can to self-quarantine for at least a few additional days – ideally a week – after the resolution of symptoms. We don’t know for sure yet whether there’s post-symptomatic shedding (yes, that’s the technical term!), but everything about the current situation suggests that extra caution is prudent, particularly given reports of resurgent infections.

Are children and infants really at low risk?

All evidence suggests that they are at indeed at very low risk for severe infection, which is both reassuring and intriguing. The mechanism is unknown at this point. They can still get infected, though, and they can probably transmit, so there’s good reason to close schools – not to protect children, but to protect parents, teachers, and staff.

Do masks help?

Consumer-grade masks won’t protect you from getting sick, but they will protect others from you if you get sick and don’t know it. And given that there seem to be a number of COVID transmissions from asymptomatic and/or presymptomatic individuals, that matters. Wear one if you own one, or make one.

Does handwashing help?

Yes, absolutely. Also produces good memes.

Is it airborne?

The “airborne” question bedevils scientists trying to communicate with the public. It combines a locus of substantial public fear with a question of true scientific nuance—a recipe for a misinformation mess. In brief: it’s probably not as easily trasmitted as something like measles, but people should absolutely maintain distance and wear masks, and try to stay in well-ventilated places, and doctors absolutely need appropriate protective equipment. In less brief, I’ve written a post about what “airborne” does and doesn’t mean when we’re talking respiratory viruses.

How long does this stick around on surfaces? Should I pick up my mail if the postal worker gets sick? Should I worry about doorknobs?

Some colleagues and I recently published a paper about this. Basic takeaways:

  1. Sticks around for long enough that surface transmission is definitely plausible
  2. Comparable to SARS-CoV-1 (the closely-related virus that caused the 2003 outbreak). But this one is harder to contain. Our results suggest that this isn’t because it sticks around longer, rather is due to other things (asymptomatic and/or presymptomatic transmission probably plays a big role).

I heard that it’s “mutating”. Sounds suspiciously like a disaster movie. Should I be scared?

Not necessarily. Outside the world of Hollywood virology, it’s not intrinsically scary to see a virus mutate. In fact, it would be stunning if we didn’t. I explain this in depth in a full-length post.

Is that COVID-19 meme my angry uncle is sharing on Facebook real info, or is it fake news?

Gonna go with fake news.

Dylan H. Morris
Dylan H. Morris
Postdoctoral Researcher, Ecology & Evolutionary Biology

I’m a Postdoctoral Researcher in Ecology & Evolutionary Biology interested in mathematical biology, virus ecology and evolution, and population genetics