Highlights of Conference call with Coronavirus expert
(A) The fatality rate is probably only 0.8%-1%
(B) Three things the virus does not like
(C) Cleanliness helps alot
(D) Higher recovery rate
(E) Less severe than SARS
Forwarded: Conference call with Coronavirus expert
Overnight in Asia, we hosted a call with professor John Nicholls a clinical professor in pathology at the University of Hong Kong and expert on coronaviruses. He was a key member of the research team at the University of Hong Kong which isolated and characterized the novel SARS coronavirus in 2003. He’s been studying coronaviruses for 25 years.
Below is an abstract for the laymen.
Quick summary: look at the fatality rate outside of Wuhan - it’s below 1%. The correct comparison is not SARS or MERS but a bad cold which kills people who already have other health issues. This virus will burn itself out in May when temperatures rise. Wash your hands.
1. What is the actual scale of the outbreak? How much larger is it compared to the official “confirmed” cases?
People are saying a 2.2 to 2.4% fatality rate total. However recent information is very worthy - if you look at the cases outside of China the mortality rate is <1%. [Only 2 fatalities outside of mainland China]. 2 potential reasons 1) either china’s healthcare isn’t as good – that’s probably not the case 2) What is probably right is that just as with SARS there’s probably much stricter guidelines in mainland China for a case to be considered positive. So the 20,000 cases in China is probably only the severe cases; the folks that actually went to the hospital and got tested.
The Chinese healthcare system is very overwhelmed with all the tests going through. So my thinking is this is actually not as severe a disease as is being suggested. The fatality rate is probably only 0.8%-1%. Basically, this is a severe form of the cold.
2. Your colleague at HKU estimated that the size of the infected population on Jan 25th was 75K with a doubling time of 6.4 days. So by 1 Feb we would have 150k infected. How accurate do you think these models are and how accurate have they been in the past?
Those figures did not take into account restriction on travel, quarantine etc… These reports are likely on the high side. This is not taking into account social distancing. Historically these models have not been all that accurate.
3. When do you think this thing will peak?
Three things the virus does not like 1) sunlight 2) temperature and 3) humidity.
Sunlight is really good at killing viruses. That’s why I believe that Australia and the southern hemisphere will not see any great infection rates because they have lots of sunlight and they are in the middle of summer. And Wuhan and Beijing is still cold which is why there’s high infection rate.
As regards temperature, the virus can remain intact at 4 or 10 degrees for a longer period of time. But at 30 degrees then you get inactivation.
The virus doesn’t like high humidity either. That’s why I think Sars stopped around May and June in 2003. The environment will be unfavourable for growth around May. The evidence is to look at the common cold – it’s always during winter. So the natural environment will not be favourable in Asia in about May.
The second factor is that of personal contact.
With Sars once it was discovered that the virus spread through the fecal oral route there was much less emphasis on the masks and far more emphasis on disinfection and washing hands. HK has far more cleanliness (than China) and they are very aware of social hygiene. And other countries will be more aware of the social hygiene (than China). So in those countries you should see less outbreaks and spreading.
A couple days ago the fecal-oral route of transmission was confirmed in Shenzhen. In China, most of the latrines are open- there’s more chance of the virus being spread.
4. Have we seen any super spreaders? We saw that with Sars and Mers.
There’s talk about that but the epidemiologists are still overwhelmed so no clear answer. But I don’t think there are any super spreaders.
5. What is the percentage of people transmitting the virus while being asymptomatic?
Patients were symptomatic at about day 5, some of these cases may be asymptomatic until about day 7. That’s based on the first publications. Asymptomatic is probably the first 5 days.
There’s a paper published looking at a familial cluster with a boy who was shedding the virus and he was asymptomatic.
That’s something about kids and we saw with Sars. Very few kids had very severe disease. We are trying to determine if this is a virus which we call low (unintelligible) kind of inducer or high (unintelligible) kind of inducer. SARS is high [unintelligible] kind of inducer. This means that when it infects the lower part of the lung, the body develops a very severe reaction against it and leads to lots of inflammation and scarring. In SARS what we found is that after the first 10 to 15 days it wasn’t the virus killing the patients it was the body’s reaction.
We are doing testing on this now. Is this virus in the MERS or SARS kind picture or is this the other type of virus which is a milder coronavirus like the NL63 or the 229. I think this will be a mild (unintelligible) kind inducer.
6. Are you seeing any difference among the young population and older population in terms of mortality rate?
SARS went really for people in their 30 or 50 years. And MERS on the other hand basically people who have co-morbidity.
The data coming out of China seems to indicate that it’s those with co-morbidity are most at risk. For the seasonal influenza that’s also what we find. It’s the people with co-morbidity that have a higher mortality rate.
This looks more like the seasonal influenza where those who die have co-morbidity. Now that we have better case control definitions outside of mainland China, we will get a true assessment of the fatality rate. I would now put it at about 0.8% to 1% when you look at all the death reports.
At this stage it’s a really bad cold which can cause problems in people. People are talking about the “lethal virus” but seasonal influenza can cause deaths in elderly but we don’t call that “the lethal influenza”
7. There’s news reports that antivirals are being used and that it’s working what are your thoughts on that?
With SARS it didn’t seem to work at all with the commercially available antivirals. But there seems to be good effects with the case in Washington with the Gilead agent. And it sounds like China will be using it.
Interferon works and it has quite a bit of benefit.
8. The recovery rate now is higher than the deaths rate? What does it mean for a patient to have recovered?
What we found is that in HK with SARS we didn’t know how long to treat a patient for. Now in China they are using the SARS model but treating patients for shorter time periods so that they don’t get the secondary problems that they did with SARS.
I’d consider a patient recovered if he’s been discharged. The problem is that with SARS, there were quite a bit of people where the steroid were very beneficial to treat the acute stage and we didn’t know how long the virus would live for so we kept them on the steroids for a long period of time and they came out with all sorts of secondary problems.
9. What is the probability that this will be contained and eradicated or will it be endemic in the human population?
If it is like SARS it will not be endemic. It most likely will be a hit and run just like SARS. People talk about mutation but what we found with SARS was that there was no mutation and we have been tracking MERS and we have not seen any severe mutation. This is unlike the common coronavirus which when they replicate they don’t have a ”spell check” so they mutate. So if this virus follows the same path as SARS or MERS it won’t mutate. This will not be endemic. I think it will burn itself out in about 6 months.
10. Does mortality rate typically increase over time? That was apparently the case with SARS.
With SARS we didn’t know how long the virus was alive for. So with SARS in the later stages people were not dying of SARS but of the complications of SARS which is why the mortality rate increased. But now people are much more aware of the dangers of over immunosuppression. So the death rate shouldn’t be more severe.
In Hubei, the milder cases are not making it to the hospital. Because they are so overwhelmed that milder cases are being sent away. So that’s why it’s important not to look at the mortality rate in Wuhan but to look at the mortality rate in Shanghai or Shenzhen or outside of Wuhan. It’s very important to dissect it out.