Chinese officials reported 1,886 new cases of the coronavirus Tuesday — the first time since Jan. 30 the daily figure has fallen below 2,000. It also reported its lowest daily death toll in a week.

But the World Health Organization (WHO) said data suggesting the epidemic had slowed should still be viewed with caution. The news comes as Liu Zhiming, the head of a leading hospital in China's central city of Wuhan — the epicenter of the coronavirus outbreak — died of the disease, becoming one of the most prominent victims since the disease first appeared at the end of last year.

Related: What to call this new coronavirus? Some cautionary tales.  

The coronavirus outbreak has brought with it a deluge of information — both reliable and unreliable. The WHO is calling all it an “infodemic.”

What do we know and what don't we know about COVID-19, the disease that causes the coronavirus? Dr. Michael Mina, is an infectious disease specialist at Harvard's T.H. Chan School of Public Health, as well as Brigham and Women's Hospital in Boston. He works with colleagues to understand what the outbreak looks like, how this virus is spreading, and how to develop advanced diagnostic tests.

Related: The global ripple effects of the coronavirus outbreak

We spoke with Mina on Feb. 3, 2020, just as the WHO had confirmed 7,700 people had tested positive for COVID-19. On Tuesday morning, China reported more than 72,000 cases to WHO, including 1870 deaths.

The World’s Elana Gordon hosted a Facebook live Q&A with Dr. Michael Mina on Wednesday, Feb. 19. at Harvard’s T.H. Chan School of Public Health.

The WHO says we still have a chance of preventing a broader global crisis.

Mina suggests COVID-19 is following the expected spread for a virus like this and that it has been increasing exponentially although lately, at least in China, it seems that the spread has appeared to start slowing down. "So I would say, from an epidemiological perspective, it's actually followed the characteristic dynamics that we would have anticipated," he said.

Marco Werman: And for an epidemiologist, is that a concern that it's following the predicted spread?

Dr. Michael Mina: It is, for a virus like this. We know that the predicted spread is going to be exponential. And so that's because every individual who becomes symptomatic and spreads it, spreads to — in this case — more than one person. And so that suggests that we want to try to contain this as quickly as possible before it gets entirely out of control.

For you, how contagious is this disease?

Normally, I'm studying measles. And so for me personally, I think that this is not the most contagious or transmissible pathogen that we are normally concerned [with] as humans. But given the severity that seems to be occurring, it seems to be maybe spreading a little bit more rapidly than an influenza virus, for example. So I think it's quite disturbing how quickly it's spreading.

But as we're hearing from any number of medical professionals here in the states right now, really, the first concern should be right now for us in the United States, the flu?

On the one hand, if we're talking about how many people are currently getting infected and dying, the flu is absolutely the major concern at the moment in terms of numbers. But with the coronavirus virus, we at least feel that we have an opportunity to prevent the introduction of a whole new pathogen. So I think the activities surrounding coronavirus is going to be ramped up.

Dr. Mina, what have you been learning about the severity of the actual illness from the coronavirus and who is most at risk?

So there was actually a Chinese government paper put out yesterday (Monday), and this actually was the first real good glimpse into what the severity is really looking like across ages. And as anticipated from what we've heard and the reports that we've been able to glean over the last month or so, it's very much a virus that's affecting more severely the elderly and really individuals over 40, but particularly over 60 or 70. We've seen in children very, very few, even case reports, no less, very small numbers of actual severe cases or deaths. So the severity does seem to be higher than any public health practitioner or physician would like. In people above the ages of 80, it's actually somewhere in 14 percent of reported cases. And overall, it seems to be tracking around 2 percent overall, but in particular in adults.

So 2% fatality rate overall of reported cases?

And that is a very important distinction because there is a very good likelihood that there are actually very large numbers of people in China currently who are potentially completely asymptomatic or so mild that they're not being reported at all. And I personally think that it's probably the real numbers of people who have who've acquired the virus might be over a million in China. So I'm concerned that the spread might be actually larger than we are currently actually being able to detect. But what that actually means is that the case fatality rate in terms of the actual numbers of people who come in contact and acquire the virus, if it really is a million that actually would bring down the overall case fatality rate quite significantly. And that's why I think it's very important what we're talking about, especially deaths, with regard to any pathogen, we make a distinction of among what group we're talking about. And at this point, given how stretched the health care system likely is in China, I think it's probably, really, the more moderate to severe cases who are probably presenting to the clinics and actually getting reported.

When we talk about the severity of a disease of this coronavirus, what are we actually talking about?

Traditionally, what we would think about a severe disease as being a disease that really put somebody into the hospital. And in the case of this disease, that usually presents as very severe respiratory symptoms. Pathology data has come out to understand what a severe disease looks like. And this virus does seem to really be sort of destroying people's lungs when they have severe disease.

In patients who get COVID-19 and it's mild, what does it look like?

If a patient has a mild infection that usually looks like what you'd normally think of as either a severe cold or a mild flu infection where you might have to take a few days off from work, but ultimately you fully anticipate recovering and going back to normal activities.

So as countries around the world prepare for the possible spread of COVID-19, there's this big question about how to test for it — whether labs are set up and ready. How do you test for it and how would that happen in the US or even at your hospital, Brigham and Women's?

You know, the major tests that the world has been basing all these confirmed cases on is a PCR — a molecular test — where we actually look for a little bit of the viral genome. And that's because this tool is very, very sensitive to pick up viruses. So we create PCR tests or Polymerase Chain Reaction molecular tests. And, that's what they're doing in China. And that's what we would be doing here. And we are trying to get these tests up and rolled out in our own hospital at Brigham.

And how is that test working?

So well, we haven't had any patients, thankfully, to test it on in Brigham, and we're actually just starting to get it setup. The CDC (Centers for Disease Control and Prevention) actually is currently really taking responsibility — they're supposed to be taking responsibility anyway — for all of the testing that's being performed in the United States. They had created these test kits which went out to all the public health labs across the United States. These are state labs that do that do testing such as this. And unfortunately, there was a hiccup and it's still not fully clear what really went wrong there. But the test kits didn't work. So sort of all the all the tests that need to be done are currently still being done at CDC and hopefully they'll get new test kits out to the state labs in the near future.

How prepared is this country? And, not just prepared to deal with it, but also diagnose it?

I hope we learn from this and I hope in the next one we're more prepared. I would say we're not entirely prepared as a country right now. Diagnostic testing has not really been rolled out in a way that is commensurate with the risk that's inherent in this virus. And, the reason that diagnosis is — an accurate diagnostics are important — is to really maintain, not just to find the patients who are positive, but to maintain normal functioning of the hospital system. If we have to quarantine every patient that we just wonder if they're positive, even if they all turn out to be negative — we really need to know that before we can release them from quarantine in the hospital and free up bed space for regular patients.

And finally, treatments. China has dozens of clinical trials now underway. From what I understand to test different treatments, what do you see as promising right now? Or, maybe should I say, what is the reality of finding treatments and even a vaccine for this illness?

I think that the idea of finding a vaccine is probably higher than finding a really curative treatment that's going to sort of cure anyone who gets severe disease. We would all love to find a really good antiviral therapy that we can give to somebody in critical care. We'll just have to see how those clinical studies turn out. In terms of vaccines, there has, of course, been a huge flurry of activity of companies trying to develop new modern vaccines, RNA (ribonucleic acid) and DNA (deoxyribonucleic acid) based vaccines and such. And,  I do feel confident that these will come out. I think it's just a matter of time. My guess is they won't become widely available at least until late summer, if not a year from now.

Reuters contributed to this report.

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