Coronavirus: How dangerous a threat?

[djpbaltimore]

The NY case and one of the FL cases are pretty straightforward as they both have been traveling to areas of infection (Iran or Italy). The other FL case is more troubling as it was in a man who has not traveled abroad, so likely another case of community spreading. They live in different counties in FL, so there is no obvious connection between the two.

Everything suggests that it started in China late last year. But with the connectedness of our modern world, it would've taken really draconian measures much earlier than was done to even have hoped to contain it geographically. But testing has been sparse before this week in the USA, so that they are now popping up everywhere is not terribly surprising, and makes the spread seem more rapid than it actually is. The sequencing of strains from WA indicates that it has been spreading for the past 6 weeks unmonitored. Expect more positives.

 

[nevele neves]

The over hyped panic is also doing no one any good.

 

[Koronin]

The NY case and one of the FL cases are pretty straightforward as they both have been traveling to areas of infection (Iran or Italy). The other FL case is more troubling as it was in a man who has not traveled abroad, so likely another case of community spreading. They live in different counties in FL, so there is no obvious connection between the two.

Everything suggests that it started in China late last year. But with the connectedness of our modern world, it would've taken really draconian measures much earlier than was done to even have hoped to contain it geographically. But testing has been sparse before this week in the USA, so that they are now popping up everywhere is not terribly surprising, and makes the spread seem more rapid than it actually is. The sequencing of strains from WA indicates that it has been spreading for the past 6 weeks unmonitored. Expect more positives.

I suspect in the US it's likely we'll never actually know full numbers as many who may have it will never go to a doctor or hospital and never get tested in the first place. Also read the tests in the US aren't accurate due to contamination or something.

 

[Merckx index]

If you want a model country to follow, I'd take Japan. I really don't understand why Abe is taking so much flak. Japan has more than twice the population of S. Korea, yet < 10% of confirmed cases, not including the Diamond Princess--and there is a relatively slow appearance of new ones.. At least part of the reason is common-sense and relatively easy to bear restrictions. They've closed all schools for this month; education is one activity that can be carried out almost as well online as face-to-face. They've banned attendance at some sporting events. Again, fans might not like this, but they can follow the sports online or on TV. Workers are urged to telecommute when possible.

And as I suggested, the ramping up of testing in S. Korea and other locales is showing a much lower mortality rate. And I believe the test is still missing asymptomatic individuals. A retrospective analysis of antibody responses will likely be a better measure of that.

The mortality rate in China is actually close to 4%. The mortality rate outside of China, excepting S. Korea, is about 2.4%. It 's less than 1% in S. Korea, but their testing protocol, while it will probably catch more people with very mild or no symptoms, depends on voluntary appearance at testing sites, which could bias the sample towards younger people who are known to have a much lower mortality rate. Also, the outbreak began in S. Korea among members of a secretive religious cult, which I believe is composed predominantly of younger people. The data from S. Korea are certainly worth paying attention to, but I'd want to see an age distribution of the tested population before coming to conclusions based on one nation.

Another probably relevant factor is the rate of new cases. In S. Korea, as many as 500 new cases have been reported daily recently. Many if not most of those cases will be individuals who only recently experienced symptoms, whereas it usually takes some time for the disease to develop to the point of death. IOW, deaths may lag new cases, resulting in an under-estimate of the mortality rate. We have seen this in China, where the nominal mortality rate was about 2% in the early stages of the outbreak, and only later has increased to its current level of about 3.7%. It may increase further, because the mortality rate relative to the total number of recovered cases is about 6%. As I predicted upthread, that rate has continued to fall over time, as deaths catch up to total cases, and recovered cases catch up to deaths, but three is still a huge backlog of active cases, and we don't know how many of those will lead to death. In China, where the rate of new cases fell to less than 1% of total cases some time ago, the mortality rate relative to total closed cases is about 5.85%. That at least suggests an upper limit for the mortality rate, even if there were no asymptomatic or mild cases not tested.

Finally, with regard to young children, the sample size in the study reporting no deaths in this cohort was rather small, less, less than 500. Given the same death rate as adults under 70, 0.2%, we would expect only one death in that sample, and certainly no deaths does not indicate a rate significantly lower than that. So we need more data before concluding that young children are at less risk, let alone no risk, of death.

 

[djpbaltimore]

The mortality rate in China is actually close to 4%. The mortality rate outside of China, excepting S. Korea, is about 2.4%. It 's less than 1% in S. Korea, but their testing protocol, while it will probably catch more people with very mild or no symptoms, depends on voluntary appearance at testing sites, which could bias the sample towards younger people who are known to have a much lower mortality rate. Also, the outbreak began in S. Korea among members of a secretive religious cult, which I believe is composed predominantly of younger people. The data from S. Korea are certainly worth paying attention to, but I'd want to see an age distribution of the tested population before coming to conclusions based on one nation.

Another probably relevant factor is the rate of new cases. In S. Korea, as many as 500 new cases have been reported daily recently. Many if not most of those cases will be individuals who only recently experienced symptoms, whereas it usually takes some time for the disease to develop to the point of death. IOW, deaths may lag new cases, resulting in an under-estimate of the mortality rate. We have seen this in China, where the nominal mortality rate was about 2% in the early stages of the outbreak, and only later has increased to its current level of about 3.7%. It may increase further, because the mortality rate relative to the total number of recovered cases is about 6%. As I predicted upthread, that rate has continued to fall over time, as deaths catch up to total cases, and recovered cases catch up to deaths, but three is still a huge backlog of active cases, and we don't know how many of those will lead to death. In China, where the rate of new cases fell to less than 1% of total cases some time ago, the mortality rate relative to total closed cases is about 5.85%. That at least suggests an upper limit for the mortality rate, even if there were no asymptomatic or mild cases not tested.

Finally, with regard to young children, the sample size in the study reporting no deaths in this cohort was rather small, less, less than 500. Given the same death rate as adults under 70, 0.2%, we would expect only one death in that sample, and certainly no deaths does not indicate a rate significantly lower than that. So we need more data before concluding that young children are at less risk, let alone no risk, of death.

Earlier in this thread you suggested that 50-100 million people would probably die if this virus spread worldwide. I don't understand why you think the 2% number you used before is more accurate given that we know it was heavily biased by serious cases diagnosed at the onset of the epidemic. This also happened during swine flu when the early estimates were much higher than the actual numbers for similar reasons.

I don't know any authority who suggests that the death rate is higher than 2% as you seem to be hypothesizing. IMO, you are reading way too much into the numbers from China. Especially given that nearly half the men smoke cigarettes, which may be playing a role in the morbidity. Singapore has had over 100 cases without a fatality. Germany nearly 200. The SK data is the best we have because it is the only country so far that has really attempted to test on a large scale and their number is more like 0.5. Calculating death rate requires that you have some idea of the denominator. That is still a big question.

 

[Sciatic]

Earlier in this thread you suggested that 50-100 million people would probably die if this virus spread worldwide. I don't understand why you think the 2% number you used before is more accurate given that we know it was heavily biased by serious cases diagnosed at the onset of the epidemic. This also happened during swine flu when the early estimates were much higher than the actual numbers for similar reasons.

I don't know any authority who suggests that the death rate is higher than 2% as you seem to be hypothesizing. IMO, you are reading way too much into the numbers from China. Especially given that nearly half the men smoke cigarettes, which may be playing a role in the morbidity. Singapore has had over 100 cases without a fatality. Germany nearly 200. The SK data is the best we have because it is the only country so far that has really attempted to test on a large scale and their number is more like 0.5. Calculating death rate requires that you have some idea of the denominator. That is still a big question.

I think it's still hard to get a good read on the fatality rate in countries with smaller number of cases, because the true number of infected people is unknown. Within my county (Seattle is in King County, Washington), as of two minutes ago, there have been 9 deaths out of just over 20 confirmed cases of COVID-19. But the genome-sequencing hypothesis is that there are already 500-1,000 infected people in the two-county area (there are a few cases north of here). So until we have really big population samples of folks who had the the virus and recovered and the number who had the virus and died, we won't have a very accurate rate.

 

[Koronin]

Now 1 confirmed case in North Carolina. The report said the person who has it in NC had recently come back from Washington state. So likely picked it up there.

 

[Merckx index]

Earlier in this thread you suggested that 50-100 million people would probably die if this virus spread worldwide. I don't understand why you think the 2% number you used before is more accurate given that we know it was heavily biased by serious cases diagnosed at the onset of the epidemic.

Well, in the first place, some authorities are predicting as much as 70% of the global population might become infected. That's more than five billion people. Even at a 0.7% mortality rate, about what S. Korea has currently, that's close to 40 million deaths..

Second, as I pointed out, there are two ways to determine current mortality rate, by dividing number of deaths by total cases, or deaths by closed cases. These give very different results, but as the virus stops spreading and the number of cases stablizes, the two numbers should converge. In China, where the number of cases is stabilizing (and yes, this could be temporary, the virus could take off again suddenly), we see the rates converging. Early in the outbreak, the first rate was about 2%, and the second was at least 13%. maybe higher. Now the first rate is close to 4%, while the second is a little below 6%. This suggests that in China, the mortality rate is somewhere between these two values.

I agree that there are probably a lot of cases with no or relatively mild symptoms that China has missed. That's why I said this number was only a ceiling. How much lower it will prove to be will depend on how many cases are being missed.

 

[movingtarget]

Panic buying happening in many countries now. Supermarkets being cleaned out in items like toilet paper, hand wash etc............Australia and the USA have just cut their interest rates re the economic slowdown.

 

[Archibald]

Panic buying happening in many countries now. Supermarkets being cleaned out in items like toilet paper, hand wash etc............Australia and the USA have just cut their interest rates re the economic slowdown.

hand wash buying I get, but loo paper???
it's not even a virus that gives you the runs...
if people think they'll be stuck home for months, surely you'd be getting other stuff instead of buying 50 bog rolls...

 

[movingtarget]

hand wash buying I get, but loo paper???
it's not even a virus that gives you the runs...
if people think they'll be stuck home for months, surely you'd be getting other stuff instead of buying 50 bog rolls...

Yeah it makes no sense but it seems the warehouses like Costco are raking it in with all the bulk buying.

 

[Archibald]

Yeah it makes no sense but it seems the warehouses like Costco are raking it in with all the bulk buying.

soon to be followed by several months of no sales

 

[Nirvana]

When last week the supermarkets got raided here the toilet paper was the first thing that come to my mind but apparently people raided especially meat and pasta, from all the pasta types only the infamous penne lisce survived.

Note that here there is only one case in the entire province and 19 in the whole region (of which 13 in a small town on the Monte Amiata) so maybe it's different where there is a big number of infected.

 

[Nirvana]

In the last two days there has been a big bump in the deaths in Italy (mainly in Lombardia), 18 on Monday and 27 yesterday, and also the people in intensive care has increased considerably to 229 (again mainly in Lombardia). I wonder if the crying for a "return to normality" (based only on the fear of economic losses) from the government seen in the last week or so will go on or finally they'll start to lock more than the initial 10 towns.

If someone is interested the Protezione Civile has published also the number of tests done (the last column).

http://www.protezionecivile.gov.it/documents/20182/1221364/Dati+Riepilogo+Nazionale+3marzo2020/57f6b925-77fa-42de-b9cc-1274639de77e

 

[Nirvana]

That's the data in Italy as of 18:00 today from the Protezione Civile:

*29387 tested.
*3089 total cases.
*2706 at the moment infected.
*295 at the moment in intensive care.
*276 recovered.
*107 deaths.

The situation is still worsening in Lombardia, especially the deaths and intensive care while the number of new infected is stabilized around 400/500 per day, and less considerably in Emilia. In Veneto where there was one of the original cluster the number of new infected has slowed down considerably (only 27 today) whereas in other areas there are still only limited (Piemonte and Marche) or isolated (everywhere else) cases popping up.

 

[djpbaltimore]

Well, in the first place, some authorities are predicting as much as 70% of the global population might become infected. That's more than five billion people. Even at a 0.7% mortality rate, about what S. Korea has currently, that's close to 40 million deaths..

Second, as I pointed out, there are two ways to determine current mortality rate, by dividing number of deaths by total cases, or deaths by closed cases. These give very different results, but as the virus stops spreading and the number of cases stablizes, the two numbers should converge. In China, where the number of cases is stabilizing (and yes, this could be temporary, the virus could take off again suddenly), we see the rates converging. Early in the outbreak, the first rate was about 2%, and the second was at least 13%. maybe higher. Now the first rate is close to 4%, while the second is a little below 6%. This suggests that in China, the mortality rate is somewhere between these two values.

I agree that there are probably a lot of cases with no or relatively mild symptoms that China has missed. That's why I said this number was only a ceiling. How much lower it will prove to be will depend on how many cases are being missed.

It is my understanding that the experts who are predicting a worldwide spread are assuming that there will be a lot of under the radar transmission and asymptomatic cases. Correct me if I am wrong, but did the people you heard/ read predict this degree of spread estimate a death toll? Conversely, if most infections lead to clinical sequelae with a high death toll, it should be easier to contain and prevent from becoming a serious pandemic.

Regardless, the US needed to ramp up testing last week and it is starting to get glaringly irresponsible to be dawdling over testing now. The fact that we don't even know whether we need to execute mitigation strategies is a giant red flag.

 

[Merckx index]

*29387 tested.
*3089 total cases.
*2706 at the moment infected.
*295 at the moment in intensive care.
*276 recovered.
*107 deaths.

Notice how few have recovered so far. It's even more glaringly obvious in S. Korea, where there are > 5000 cases, but < 1% have recovered. This is because it takes time to recover--and to die--so when the virus is spreading rapidly, and new cases per unit of time are a high % of total cases, closed cases (recovered + deaths) will lag far beyond the total cases.

This means that the nominal mortality rate (deaths/cases) in S. Korea is definitely an underestimate, and assuming that further testing and cases involve the same demographics, that rate has to rise. A very simple way to see this is to imagine that the virus immediately stopped spreading, so there were no new cases. The total number of cases thus would be fixed, stable. But the number of deaths would increase, because most of those cases aren't yet closed, and some of them will result in deaths.

To repeat, there are two ways to determine mortality rate, deaths/total cases, and deaths/closed cases. As long as the virus isn't contained, the first will give an underestimate, but the latter an over estimate (in S. Korea, that rate is a whopping 46%). The deaths/closed cases is an over-estimate, apparently, because there are stringent requirements for classifying someone as recovered, involving two negative tests, and it generally takes several days (or more, if facilities are stretched) to get test results. That period of time, of course, is in addition to the time for the symptoms to subside, which has to occur before testing begins. Whereas most deaths, again, I'm speculating, come sooner. So recoveries lag behind deaths, while deaths lag beyond total cases.

It is my understanding that the experts who are predicting a worldwide spread are assuming that there will be a lot of under the radar transmission and asymptomatic cases.

That's probably correct. But as I just pointed out, the current estimate of the mortality rate in S. Korea has to be an under-estimate. We'll get a better idea of what that rate is eventually, but based on what we've seen in China, the rate could easily double, to about 1.5%. That's not taking into account asyptomatic cases. But if they doubled the number of total cases, the real rate would be again back at about 0.7%.

In fact, my estimates for S. Korea are closely in line with the best data we currently have concerning asymptomatic cases, from the Diamond Princess. Slightly more than one half (55.5%) of the 700 people who tested positive were asymptomatic, and the mortality rate was 6/706 = 0.85%. That's the nearest thing to a controlled laboratory experiment we're going to get, though the sample size is relatively small.

However, it should be pointed out that cruise ships tend to attract older people, so the demographics probably were skewed to people at greater risk for dying. I haven't been able to get an age breakdown of the passengers on the DP, but according to a report on the cruise ship industry in general, the average age of a passenger is 47, while the median age was somewhere in the 60s. There is a big difference between mean and median, because while there are relatively few younger people, some of them include young children, which lowers the average. In any case, a cruise ship's passenger population is definitely skewed to older people. The mean and median age of people in the U.S. is in the late 30s. But older people may also be more likely to become infected, which could cancel out this effect.

Conversely, if most infections lead to clinical sequelae with a high death toll, it should be easier to contain and prevent from becoming a serious pandemic.

Agreed. But the mortality rate is not that high, even the highest possible estimates indicate < 5%, and most of those are older people. These people (like me) are less likely to work and interact extensively with other people than younger people, so are probably less likely to spread the virus.

I do see some good news in the statistics. Since new cases have dropped to a trickle, at least for the time being, in China, we can get a good estimate of not only the mortality rate, but the % of cases that are serious or critical. The total number of such cases (serious/critical + deaths) is about 12% of total cases. That's significantly lower than the 20% figures than an earlier study reported. This % may be more important than the mortality rate, since it will determine to what extent patients need to be hospitalized. That in turn affects the capacity of medical systems to deal with the disease, as well as the extent of disruption of economic activity.

How has China done it? According to this article, it hasn't all been quarantines, and other drastic measures, though it does require authoritarian power:

Chinese government algorithms can estimate the probability that a given neighborhood or even an individual has exposure to Covid-19 by matching the location of smartphones to known locations of infected individuals or groups. The authorities use this information to use limited medical resources more efficiently by, for example, directing tests for the virus to high-risk subjects identified by the artificial intelligence algorithm.

All smartphones with enabled GPS give telecom providers a precise record of the user’s itinerary. Smartphone users in the United States and Europe can access their own data, but privacy laws prevent the government from collecting this data. China has no such privacy constraints, and telecom providers have used locational data for years for advertising.

A Chinese bank executive reports that his company purchases locational data from telecom providers. “If you have walked by an auto dealership three times in the last few weeks, we send you a text advertising an auto loan,” the executive said. “We wouldn’t be allowed to do that in the West.

https://asiatimes.com/2020/03/china-suppressed-covid-19-with-ai-and-big-data/

The article also claims that the infection rate in Wuhan--where the vast majority of cases have been--was elevated by the authorities preventing exodus of citizens not yet exposed to the virus. IOW, the situation was something like the Diamond Princess, but on a much larger scale.

 

[movingtarget]

Australia had it's first nursing home death from Coronavirus and also it's first infection of a health professional. Although the nursing home death infection is yet to be confimed 100% as Coronavirus. Obviously death by Flu or Pneumonia in nursing homes is quite common.

 

[Koronin]

It is my understanding that the experts who are predicting a worldwide spread are assuming that there will be a lot of under the radar transmission and asymptomatic cases. Correct me if I am wrong, but did the people you heard/ read predict this degree of spread estimate a death toll? Conversely, if most infections lead to clinical sequelae with a high death toll, it should be easier to contain and prevent from becoming a serious pandemic.

Regardless, the US needed to ramp up testing last week and it is starting to get glaringly irresponsible to be dawdling over testing now. The fact that we don't even know whether we need to execute mitigation strategies is a giant red flag.

The problem with this is cost. Most people can't afford the cost of the test even if they have insurance. I'm not entirely sure we'll ever get accurate numbers unless the cost gets figured out. Also many choose not to get tested anyway due to not being able to afford time off work.

I heard some of these experts seem to think the numbers in the US could currently be worse than China, but due to very little testing there's no way to know.

 

[Merckx index]

The problem with this is cost. Most people can't afford the cost of the test even if they have insurance. I'm not entirely sure we'll ever get accurate numbers unless the cost gets figured out. Also many choose not to get tested anyway due to not being able to afford time off work.

The test is supposed to be offered free. The person only pays for associated costs, such as an ER visit. And in NY state, at least, the governor has just issued a directive to cover all costs associated with testing, so it should be entirely free.

I heard some of these experts seem to think the numbers in the US could currently be worse than China, but due to very little testing there's no way to know.

If you mean the number of infected individuals, no way are the numbers in the U.S. anywhere close to China's, though of course that could eventually change.

Another point on the mortality rate. Since this is definitely higher for older people, the overall rate is likely to be higher in nations with older populations. It's interesting to note that China's population has aged in the past several decades, due in large part because of the government's restriction on having children. Even so, less than 1% of the population is older than 80, whereas 3% of the individuals in that recent study of cases was > 80. This could mean that older people are not only more likely to die from the virus, but more likely to become infected. However, it's also important to keep in mind that in China, where extended families are common, older people are likely to be more exposed to younger people. I would think in the U.S. that older people tend to be more isolated, not at jobs, e.g., or having as many social interactions.

 

[Koronin]

The test is supposed to be offered free. The person only pays for associated costs, such as an ER visit. And in NY state, at least, the governor has just issued a directive to cover all costs associated with testing, so it should be entirely free.



If you mean the number of infected individuals, no way are the numbers in the U.S. anywhere close to China's, though of course that could eventually change.

Another point on the mortality rate. Since this is definitely higher for older people, the overall rate is likely to be higher in nations with older populations. It's interesting to note that China's population has aged in the past several decades, due in large part because of the government's restriction on having children. Even so, less than 1% of the population is older than 80, whereas 3% of the individuals in that recent study of cases was > 80. This could mean that older people are not only more likely to die from the virus, but more likely to become infected. However, it's also important to keep in mind that in China, where extended families are common, older people are likely to be more exposed to younger people. I would think in the U.S. that older people tend to be more isolated, not at jobs, e.g., or having as many social interactions.

You have a more pro active governor than some of us have. Nice that at least some states are trying to do something to get a handle on the situation.

I happen to agree more with you that the numbers here could eventually get close to China although unlikely it's currently that bad. I suspect numbers in the US could be closer to that of Italy due to some of the population areas in which there have been cases.

 

[movingtarget]

Australia had it's first nursing home death from Coronavirus and also it's first infection of a health professional. Although the nursing home death infection is yet to be confimed 100% as Coronavirus. Obviously death by Flu or Pneumonia in nursing homes is quite common.

Since been confirmed as Coronavirus. Now the Chinese are saying there could be long term damage to the lungs of some people that contract the virus. It's too early to tell if the damage will be lasting or not.

 

[Merckx index]

You have a more pro active governor than some of us have

I don't live in New York. I just noticed that NY is doing that. I think other states will have to, eventually.

The real problem with testing, I think, is that many people will have to be tested multiple times. We've already seen that in the hotel in Italy. Wherever there is a cluster of cases, and people can't move away, this issue is going to rise. It could get very expensive.

Antibody tests should be a lot cheaper, but they aren't suitable for following the spread of the virus, since it takes time for the antibodies to develop. They will help in identifying people who have recovered with no or mild symptoms, and who otherwise would not be reported as cases. If a substantial number of cases are asynptomatic, widespread antibody testing could pick that up. Somewhat analogous to political polling, if you just test a sample of people, you can get an idea of what proportion of the population has actually been infected. In fact, it would be very helpful to get data like that in China, particularly in Hubei, and in other areas where clusters have appeared such as Daegu in S. Korea and Lombardy in Italy.

Now the Chinese are saying there could be long term damage to the lungs of some people that contract the virus. It's too early to tell if the damage will be lasting or not.

I wondered about that. I saw an interview with someone who was infected with the virus, and eventually recovered, but she said she still has some trouble breathing. This is another indication that the outbreak could have a huge impact on society and economy, beyond the number of deaths.

 

[Koronin]

I don't live in New York. I just noticed that NY is doing that. I think other states will have to, eventually.

The real problem with testing, I think, is that many people will have to be tested multiple times. We've already seen that in the hotel in Italy. Wherever there is a cluster of cases, and people can't move away, this issue is going to rise. It could get very expensive.

Antibody tests should be a lot cheaper, but they aren't suitable for following the spread of the virus, since it takes time for the antibodies to develop. They will help in identifying people who have recovered with no or mild symptoms, and who otherwise would not be reported as cases. If a substantial number of cases are asynptomatic, widespread antibody testing could pick that up. Somewhat to political polling, if you just test a sample of people, you can get an idea of what proportion of the population has actually been infected.

Sorry about that. I hope more states follow NY's lead.

I've read that many of the tests in the US ended up contaminated as well. That's not helping matters either.

Just read in NH a person with flu like symptoms was told to stay home, instead he went to something party or something at Dartmouth, later was confirmed with the virus and now there's a second case in NH that is related to the first.

The antibody testing may not be a bad idea.


Edited to add this link. Apparently there is a company currently in Phase 3 testing for a treatment for this virus. (The way the article is written it says vaccine, but it sounds more like a treatment than an actual vaccine). (The article is more talking about the stock, but the info is worthwhile.)

Coronavirus vaccine could add billions in value to this one stock

Time to back up the truck on Gilead?

finance.yahoo.com

 

[movingtarget]

Coronavirus has mutated :

As scientists around the world work to better understand the COVID-19 disease, scientists in China believe they have discovered a mutation in coronavirus that is fuelling the global outbreak.
The deadly coronavirus has mutated into two strains, one of which appears to be far more aggressive.
That’s the preliminary findings from researchers at Peking University's School of Life Sciences and the Institute Pasteur of Shanghai in China, in a paper examining the “origin and continuing evolution” of what’s been officially dubbed SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2).
“Population genetic analyses of 103 SARS-CoV-2 genomes indicated that these viruses evolved into two major types,” researchers wrote in the paper published in the National Science Review.
According to the study, scientists discovered the virus evolved into two major lineages, dubbed the ‘S’ and ‘L’ types.

The S type is older, and thus considered the “ancestral version”, but accounted for about 30 per cent of cases. The L type, however, is more prevalent and accounts for about of 70 per cent of cases, researchers said.
“The L type was more prevalent in the early stages of the outbreak in Wuhan, the frequency of the L type decreased after early January 2020,” researchers noted.
“Human intervention may have placed more severe selective pressure on the L type, which might be more aggressive and spread more quickly.”
The study sheds some light on how COVID-19 is evolving and suggests that more mutations could be possible in the future – a situation that could hinder efforts to find a vaccine.
According to the UK’s The Telegraph, genetic analysis of a man in the US who tested positive on January 21 showed it was possible to be infected with both types.

However the researchers were quick to note that more research is needed to understand the significance of the study’s findings and how SARS-CoV-2 differs from other coronaviruses.
“These findings strongly support an urgent need for further immediate, comprehensive studies that combine genomic data, epidemiological data, and chart records of the clinical symptoms of patients with coronavirus disease 2019 (COVID-19),” they wrote.
COVID-19 ‘so effective at transmitting’
The discovery of what appears to be a mutation in the virus comes as cases continue to spread across the world, including Australia with new cases announced in NSW, Queensland, South Australia and Western Australia on Thursday.
Professor Ian Mackay, virologist and associate professor at The University of Queensland, says it’s clear the COVID-19 disease isn’t going away any time soon.
“We’ll just see this virus bounce around, looking for new hosts,” he told Yahoo News Australia.
“I think what happens is the virus keeps spreading in countries, there are more and more hotspots outside of China,” he said.
“We’re seeing exponential growth in a few countries around Europe, so it does look like it’s taking off.
“This virus, I think, will stay with us because it’s so effective at transmitting – like the other four human coronaviruses we live with right now,” he said.
“Those cause relatively mild disease at the moment because we’ve lived with them for so long... this virus may settle down to be more like them, or it may not.”