Xueting Qiu with a coronavirus update

Xueting Qiu, a molecular epidemiologist at the Harvard T.H. Chan School of Public Health, revisits AATB to talk about the current state of the COVID-19 coronavirus pandemic and why we needed to start social distancing yesterday.

Interview Highlights

What is the current global state of COVID-19 pandemic?

We are in the middle of viral spreading. It will be continuously spreading for a while. By March 12th, globally we have 125,048 confirmed and 4,613 deaths. Outside of China there are 44,067 confirmed and 1,440 deaths from 117 countries/territories/ areas.

In the middle of February, that is, one month ago, our center director Dr. Marc Lipsitch has said it is very likely that we will see a global pandemic. He also said, if pandemic happens and we don’t take effective controls, considering the R0 is 2, 20%-60% of adults world-wide are likely to be infected in the coming year. The unclear part would be what proportion of those will show symptoms.

Have any countries successfully contained the virus? If so, what were their strategies?

Yes. The effective strategies are: early testing on large scale of the population + case monitoring + social distancing.

We would cautiously say China has controlled it well at this point, but at a painful cost with lockdown of Wuhan and nearby cities, and also performing extremely strong social distancing. This experience may not be flexible for other countries to learn. But we know under the outbreak, it may happen for other countries, like Italy has also locked-down the whole country at this point.

Here, I will give the example of the most successful country – Singapore. What have they been doing? Singapore enjoys an exceptional capacity for high-quality outbreak investigation. It was among the first international locations to report cases of COVID-19 exported from the epicenter of the outbreak in Wuhan, but investigators went further. If you only test people who are connected to known cases, you are just one missed infection from completely losing track of the transmission chain. Understanding this, the Singapore authorities tested cases of respiratory disease that were negative for other viral pathogens, and so potentially the result of COVID-19 transmission chains that had escaped detection. They immediately found 4 cases in early February without known contacts with other cases. Diligent contact tracing has managed to keep a lid on the outbreak and, despite reporting their first case on January 23, to date, the total case number for Singapore is only 110 with no deaths (although seven are in serious condition). This is an exceptional achievement.

What is the current state of the COVID-19 pandemic in the US? 

There has been local transmission for a while, though many people still doubt it. Based on the data we saw, the US is on the same trajectory with other countries like South Korea, Italy, and Iran.

We believe local transmissions have been established in many communities in the US. Trevor Bedford [Professor of Genome Sciences and Epidemiology at University of Washington] has conducted genomic analysis which has shown that there has been cryptic transmission in Washington state for the past 6 weeks. This analysis is based on two isolates of COVID-19 from Washington state. The first one (WA1) was an imported case from Wuhan China, from Jan 21st. Then, at the end of February, a second patient from Washington state was sequenced, and this sequence clustered with the first sequence. The first and second sequence share a rare variant (a mutation on site 18060 from the viral genome, which is not present in the majority of viruses in China So you know this is most likely from local transmission in Washington. That is, the first WA1 virus has been spreading in the community for 6 weeks with the same rare variant. And from epidemiological perspective, the rapidly increasing tested case numbers in Washington also tells the same information.

There have been many reports about the CDC bungling the tests for COVID-19. Do you know why there were such difficulties creating the test? 

So I can list a few things here to say why it’s been so difficult creating massive testing for this virus:

  1. The criteria on the eligibility of who can get tested. At the beginning, it was limited to people who have direct travel history to Wuhan, China and have showed symptoms, then later to all regions of China. Only until late of last week, the CDC now allows to test people without travel history or contact tracing. With this, we have been missing all the local transmission and the imported cases from other countries that are under outbreak.  
  2. The flaws on the PCR testing kits. The redesign on the PCR testing kits has flaws. The negative control in the kit doesn’t work, resulting in many false negatives. [Editor’s note: By “false negatives”, Xueting is referring to tests that were unclear and thus no results were reported.] This caused a waste of at least a couple of weeks.
  3. The regulations on which lab can conduct the tests. This part I think is the main limitation on the testing capacity. So far, only very limited labs and staffs can do the testing run. We totally understand the underlying rationale for federal regulations of diagnostic assays, but it really creates barriers for the possibility of finding new solutions, like using high-throughput research assays for the viral testing.

But now I think the regulation has been lifted and permissions have been given to many other labs. So we may expect a higher testing capacity soon. But it will still take some time. So the limited testing capacity cannot tell the real situation of the outbreak, but we know it is severe.

At this point, is the virus containable in the US? If not, what measures will have to be implemented in order to contain it?

No, we cannot stop it anymore. We have missed the chance for weeks. Like I mentioned previously, we believe local transmissions have been established in many communities in the US. We missed the containment period, but we have to mitigate it.

Now the most important thing for now is to slow down the outbreak. Massive testing is needed. And start social distancing now. The sooner the better. You have heard of “flattening the curve” a lot recently. Why we have to slow down the outbreak? Because of the limited healthcare system capacity.

A crucial thing to understand about the coronavirus threat — and it’s playing out grimly in Italy — is the difference between the total number of people who might get sick and the number who might get sick at the same time. The US has only 2.8 hospital beds per 1,000 people. That’s fewer than in Italy (3.2), China (4.3) and South Korea (12.3), all of which have had struggles. More important, there are only so many intensive care beds and ventilators. The healthcare capacity is directly related to the case fatality in each country. Because overburdening the healthcare capacity has happened in Wuhan China, and is happening now in Italy and Iran. These locations have case fatality rates as 3~5%. But in South Korea, the case fatality is 0.9%, which can be 10 times of difference.

But we can make a difference if we act in a timely manner. Other places that hesitated when action was needed are paying a heavy price. So we have to ACT QUICKLY, and the actions are to PRACTICE BASIC HAND HYGIENE, SOCIAL DISTANCING and REDUCE GATHERING, where efforts can be made by everyone – if you can work from home, do it; if you have upcoming conferences/meetings/parades/social gathering, try to cancel/postpone them; if possible, change church gathering to remote meetings online for the critical time period, etc.

The earlier, the better. Since the outbreak is counted by day, we can change the situation by taking action even one day earlier.

What does the near and far future hold for us? How long will it take to contain this virus and return to business as usual?

It really depends on how fast we act at this critical time. It is very hard to predict when the epidemic will peak and will end. Different places may be at different stages of the outbreak at this point.

But the most important thing is that we have to take action now. Perform good hand hygiene, avoid gathering, and keep social distancing.

We hope this can be ended soon, but it is a pandemic, it will be going for a while. Let’s do what we can do. And let’s hope for the best and prepare for the worst.

Read more

Leave a Reply

Your email address will not be published. Required fields are marked *