The Second Wave

In February, I estimated the mortality rate of Covid-19 at 0.2%. So far, this limit seems to hold. There are no countries or large areas where the virus has proven more deadly.

Sure, there’s New York where 0.17% of people have died and New Jersey with 0.18%. If we look closely, county by county and suburb by suburb, we have Bronx with 0.34%.  However, Bronx has a high obesity rate, and more uninsured and poor black people who appear to be more susceptible to COVID-19. These factors naturally contribute to a higher COVID-19 mortality. Overall, the 0.2% estimate seems to hold, as a rough, but reliable guideline.

This makes COVID-19 about twice as deadly as the common flu. It has interesting complications involving the brain, heart, lungs and other organs. This is not unheard of for viruses — just think of Adenovirus 36 that is strongly linked to obesity. Colds, themselves, are caused by a wide variety of viruses including coronaviruses. So, COVID-19, welcome to the clan!

In this article, I want to look at the future. What will happen in the next few months, when fall brings lower temperatures, more rain and more … colds. COVID-19 is now firmly established as an endemic virus across the globe. No country has been spared. OK, perhaps North Korea, but it is hard to believe the North Koreans! From New York to South Sudan, we all face the same virus and, like with all viruses, modern medicine can do remarkably little to help. Thus, we should not expect to see across Africa or Brazil vastly higher mortality rates than we have seen across NY or London. In fact, India has reported a lower mortality rate in Mumbai's slums than Western Europe has because they have a younger population and because they have likely tested more.

In hindsight, the dominant feature of the first wave was rapid onset with a fast exponential growth in cases and deaths. This was due to the novelty of the virus. Everyone was susceptible and the R-factor (the number of people the average patient passes the virus to before getting cured) was high.

This R-factor depends on various things such as
— immunity — if half of the population is immune, R will halve.
— weather. Colds don’t like summer.
— social distancing

— school, work, public transport use.

Now, through various measure and through the grace of God’s summer, we the people, have brought R well below 1. This led to an exponential decay in the number of cases, but the virus has not disappeared. It may never go away. At least not in the near future.

In the second wave, the R-factor will be close to 1. It will inch slowly above 1, as cold weather makes us more susceptible to colds and people naturally share viruses more efficiently in the fall because they spend more time inside in the proximity of other people.

Thus, we will see an increase in cases, but it will be much slower than in the first wave. It will be like Iran now. The virus is there. Some people are dying, but the numbers do not change by a factor of 10 a week.

If immunity is long lasting, some places, where almost the entire population was infected will not see a serious second wave, e.g., India's slums, NYC and NJ if the death rate is what I have predicted.

If immunity doesn’t last long, such places will see a second wave of milder illness. The virus will infect adults for the 2nd time — with far milder symptoms due to some degree of immunity from the first infection. It will also infect children who were breastfed or not yet born during the first wave. Thus, like most other colds, it will do the rounds in day care centers, again, mostly with mild symptoms.

In countries where the quarantine stopped the virus successfully this summer, the second wave will be more substantial. For people who first meet the virus during the winter, we should expect more pneumonia and a higher mortality compared to those first infected in summer. This happens with all colds.

In such places, like Norway, Denmark, Austria, and perhaps parts of Germany and Eastern Europe, where most people appear to have avoided the virus in summer, we will see a lot of death and pneumonia in the fall. Sure, still of the order 0.2%, so not the end of the world. The difference between summer and winter mortality could be substantial.

How about Sweden? Sweden is interesting. Sweden’s first wave mortality was about 0.05% — about a quarter of my 0.2% rough limit. I wonder if they can get away with less. This may be due to the general good health of the Swedish people, their good discipline, good health care and low incidence of obesity. Maybe, in Sweden, this virus only kills 0.1% or, maybe, even less. It will be very interesting to see if Sweden gets and 2nd wave and how it will look like.

Iran, if we believe their numbers, has only lost 10% of the 0.2% I expect. But I am not sure I believe their numbers. I think they may be further along. We’ll see when it stops. Iran is in a stationary state, with R hovering above 1 when it rains or too many people turn on the AC and blow 1 otherwise.

A look in the Southern hemisphere — Chile has nearly reached 0.05% dead while New Zealand and Australia have very low numbers. Argentina is much lower than Chile but still on the growing exponential. Slow growing exponential. So, the Southern hemisphere doesn’t look too bad. We’ll be lucky if we’ll have it so easy in the north.

My 2 cents on politics and policy advice:

Allowing the virus to go though the population during summer will result in some degree of herd immunity. Usually, summer colds are vastly easier than winter colds — less likely to result in complications, pneumonia, etc. Thus, letting the virus go through the population now will, in the long term, save lives. Sweden has dome this experiment and is probably going to be proven right.

Austria, Denmark and Norway will probably see more deaths in the fall and perhaps Eastern Europe, Germany, too if the lockdown is the reason the numbers are low. These countries will be in a particularly bad position as they would have paid the economic cost of the lock downs — children lost school, everyone lost money, and, may have more COVID-19 deaths than if they had done nothing at all.

Italy, Spain, US, the UK and Sweden seem to be managing to pretend to be taking measures against Covid-19, but their mortality rate seems to be the same as if they had done nothing at all. Doing nothing at all to prevent the virus spreading during summer seems to be the best strategy.

I am surprised by New Zealand and Australia — they are in the middle of winter and they seem to have few Covid-19. Although, Australia is seeing an increase in cases at the moment. I didn’t believe their containment strategy would work. We’ll see if the low numbers will lasts until the end of winter.

Across the world, inflation, political instability and war appear unavoidable now.  I worry about my children, and my nephews and about their future. Will David and Edward go to war instead of college? If so, will David fight against or with his siblings in this new twisted world?

Romania confirms first coronavirus death

He was identified as the likely first corona casualty in the media and our blogpost from two days ago, while he was still alive. The terminal lung cancer patient had made his imminent death easy to predict for the doctors and to the media (the fact that our blog predicted it means I spend a lot of time inside writing on this blog and reading the news.)

The Romanian authorities have decided to do away with privacy and disclose the man's preexisting conditions and medical situation. I urge all other nations to do the same and release data that can be analysed. We are at war with this virus. There is no reason to hide behind the "pre-existing conditions". 

This is the official news: 

BUCHAREST — The Romanian government confirmed on Sunday the first death in the country due to coronavirus.

The deceased was a 67-year-old man who had been suffering from terminal cancer. He was confirmed to be infected with coronavirus on March 18 and was being treated in a hospital in the southern Romanian city of Craiova.

Romania, which has recorded 367 cases of coronavirus to date, declared a state of emergency on March 16. (Reporting by Luiza Ilie; Editing by Susan Fenton)

https://nationalpost.com/pmn/health-pmn/romania-confirms-first-coronavirus-death

How deadly is the coronavirus? A lower bound

For this estimate I will look at two of the world's most affected regions: Lombardy and Wuhan and use the data available today.

In Wuhan, the infection is over, for now, with 3000 deaths. The city has 10 million people. If everyone was infected, the death rate would have been 0.03%. If 60% of the population was infected, the death rate would be 0.05%. If the quarantine measures taken were successful and fewer people were infected, we should see a new wave of infections once life is back to normal.

In Lombardy, 2000 died so far, and there is no sign the pandemic has passed its peak. If all Lombardy residents (10 million people) were infected, a death toll of 2000 would mean the mortality of the virus is 0.02%. That's like swine flu. Sure, this is only a lower bound. The mortality is certainly higher. 

OK, so how many were tested? Lombardy has conducted 52244  tests -- ONLY about 0.5% of their population. Of those, 19844 tests were positive. That means 40% of the people tested had the coronavirus. IF we assume the people we didn't test have the same chance to be infected as the people we did test, we'd have 4 million infections at the moment with a death rate of 0.05%. 

We do know they were thrifty with the tests and tested primarily critical cases or people who met positive carriers. Even so, it is expected that the population they don't test to be less infected than those tested. However, it is believed that 70% of the cases are asymptomatic or quasi-symptomatic. Data from China suggests that 80.7% of their cases were mild, and less than 5% of the cases were critical. 

In the Italian town of Vo, they tested the whole population of 3000 people and detected 89 positive cases -- all asymptomatic patients -- BEFORE the first symptomatic case. So, if we take this as a benchmark, we assume that for every symptomatic patient, one has 100 mild or asymptomatic cases. For the 20 000 positive, symptomatic cases we have today we would have had 2 million residents infected that are quasi-symptomatic or asymptomatic in Lombardy, which would bring the death rate to 0.1%.  Now, Valeriu's plots show that the dead double about every 3 days.  The number of affected people should double at roughly the same rate. This means that the whole populations should be infected in a week or so if this lower bound were true and if the quarantine is ineffective. The total death toll would then be less scary -- somewhere between 5000 and 10000 people.

How does this compare with my guess of 0.2%?

My 0.2% guess for Lombardy's population of 10 000 000, would mean 10 000 - 20 000 deaths. For the 2000 people who died so far, we'd need one million to have been infected a few days ago. That would probably have increased to a few million by now -- already a good fraction of the total population of 10 million. If this is right, the pandemic should reach its peak in the next few days. 

If 0.2% of the people die, about one million people should have been infected a few days ago. Depending on how well the quarantine works, that number might have increased slower or faster. Sooner rather than later, however, it will have to stop as the pandemic runs out of people. 

Thus based on my 0.2% guess, I conjecture the following 

-- the quarantine in Lombardy does not prevent infection. It will however spread the peak of the pandemic and make it easier for hospitals to handle the patients. In a few days, most people would have been infected and in another few days, the pandemic will stop. By April 20, there will be no Coronavirus in Lombardy. Sure, isolated infections like in Wuhan today will still take place. 

-- Lombardy will NOT go beyond 20 000 deaths. 

-- The rest of Italy and will follow the same path, a few weeks behind. Southern provinces should have it easier with the arrival of summer weather. 

I hope my lower bound is truer than my guess because 20 000 deaths is still a lot. Either way, we should probably see the death rate plunge below the average of previous years during the months to come. 

The overall mortality will be similar in the rest of Europe. That means we'll see in Germany what we see in Italy now. So, by the end of March or in the first days of April, there should be over 3000 Coronavirus deaths in Germany as well. 

Romania's first Coronavirus Death?

The patient most likely to be Romania's first Coronavirus death has been identified. The 67 years old man has lived in France for 10 years. There, he developed lung cancer and is now in the terminal phase of  the disease. 

His wish was to die at home. For us, Romanians, dying in hospital is sad -- even if it's a posh French hospital. We like to die at home, with a priest and a candle, surrounded by family and friends. We like to say goodbye naturally rather then fight a battle we can't win. 

So... he came back. Unable to walk and travel alone, he was assisted by a French social assistant on his last flight home. What he didn't know was that, on top of the terminal cancer, he also has a coronavirus infection. 

Under normal circumstances, a normal cold in such a patient could easily lead to pneumonia and death. Today, however we have tests for Coronavirus. 

When the man went to the local hospital with terminal lung cancer and pneumonia, the doctors asked for a Coronavirus test. The test was initially refused. A few days later, a test was conducted and came positive. 

In this time, doctors and nurses have been exposed to the patient. They are now in quarantine. The emergency department of the hospital has been closed down. 

The doctors predict that, due to the underlying lung cancer and pneumonia, this patient will be Romania's first Coronavirus death. 

Here are the news: 

"The Truth" newspaper tells us the truth, this time. Terminal cancer patient expected to be Romania's first Coronavirus death. They tell us it is lung cancer, which is known to kill relatively fast and it's not debilitating until the very end. 

"The 3rd Antena" follows with news about the hospital closure and the patient's age, but instead of telling us he had terminal lung cancer, they only mention chronic health problems. Lung cancer is not a chronic problem. People die in a few months. 

Mediafax also tells us the scary bits. The hospital is closed. Its 23 medical professionals are in quarantine. They don't tell us about terminal cancer or that he will likely be Romania's first coronavirus death. 

I think knowing that the patient had terminal cancer, a life expectancy measured in weeks and that he came home with the declared purpose to die at home, is important to understand what role the coronavirus plays in this man's death (if he does die). The coronavirus kills people. However, understanding what part of life is taken away from each patient is crucial in understanding the severity of the disease. We cannot just call it a pre-existing condition. Data should be available where know what each of these people have had! That information should be made public. How much life is lost? How many years? How many happy years? We can't just count the bodies... It's not a slaughterhouse. 

Last but not least, how many like him haven't been tested? According to Romanian customs, it would have been perfectly reasonable to call the priest instead of the doctors. The priest, actually, should do a coronavirus test. I would say, certainly, test all dead people; even though here the doctors first refused to test, as it was off protocol. Calling the doctors may not have been exactly the best thing, as they are now all in quarantine and the hospital is closed. But, this way, the contacts have been traced and 5 other corona patients have been found. Otherwise, they would have continued to spread. Are there more? Maybe? Certainly?

How deadly is the coronavirus? The 0.2% revisited.

Last week, I put forward 0.2% as the most likely value for the mortality of COVID-19. In this post, I will explain my rationale at greater length and look at today's numbers to see how that prediction holds up. 

I should thank my professors Kip Thorne and David Politzer who taught me how to think. I have learned to play with order of magnitude calculations during countless office hours for Physics 1 that I spent at Caltech with David Politzer, sometimes with and sometimes without students. Kip also did this very often in his TAPIR group meetings, which, for a few good years,  were my main source of pizza. 

The situation is as follows: 

We have this new disease that is killing people. 

We don't know 

• how many are infected because we have not been able to test the entire population.
• how many are dead. Sure, countries keep publishing how many dead people have been testing positive. It is, however, true that some people die without being tested.  On the other hand, a death is still an important event. I thus believe a dead man is less likely to go unnoticed and untested than a man who displays cold symptoms. 
• the difference between the daily deaths at this time of the year and how many deaths we see now in each particular region. I would believe this number more readily than the estimates based on counting tests. 

We know we have more infected than confirmed positives. We are certain it's not less. Valeriu Predoi plots all the data from the various countries and nicely fits it to exponentials. From there, one observes some trends. Germany's death toll is much closer to being parallel to the number of cases than Italy's. The effect of the quarantine cannot be seen in the data as of yet. For Italy and for most other western countries, the deaths toll double much faster than the number of cases because they do NOT test enough. Roughly, the more a country tests, the more parallel these lines get. Countries that start testing later like the US have the number of cases doubling faster than the deaths.

The death rate in Italy is showing a hint of slowing down as is that in France and Spain due to the quarantine. It can be seen that the quarantine moves the death toll to a slower exponential, but cannot entirely stop the spread of the virus. Belgium shows a clear effect on the quarantine where the increase in the number of confirmed cases is also slowing down. This can be clearly seen for China, and recently for Ireland, Denmark, Sweden and Finland. Sweden recently decided to test only the cases requiring hospitalization. I am unsure if in the other countries the testing procedures have changed as well or if there is a working quarantine.

We don't have an antibody test as of yet. If we could test for the viral antibody, we could go to Wuhan and see what fraction of the population has developed immunity to the coronavirus. That would be an accurate measure for the number infected. 

Now... to put forward a reasonable guess for the mortality rate. What do we do? 

I thought it's reasonable to look for well-organized countries with a good health care system. Here, dead people are less likely to go untested and uncounted. So, we can believe the dead.

 It takes awhile (about 2 weeks -- because there is an incubation period) for somebody to die of COVID-19.  But how long does it take for someone to get tested? People are certainly not tested the day they get infected. They are actually more likely to get tested the day they die. The disease has an incubation period of a few days, people wait in line to get a test, the results take some time to come back and be posted online. 

I thus assumed that, with all the counting errors and delays, the number tested today is a reasonable indication for how many people were sick some 10 days - 2 weeks ago.  This assumption no longer holds if, for example, the quarantine works and the number of infected people stops growing. It will also not work if the infection has passed its peak and the virus finds it hard to find new people. Or, if the test policies change - say, if the country runs out of tests or the medical system is overwhelmed and testing is being prioritized for special cases (critically ill, politicians, etc). 

Like most order-of-magnitude estimates, it is a reasonable assumption, but, not always true. It is my best guess. 

Thus, I said, a reasonable guess, perhaps a reasonable upper bound even, for the mortality rate of COVID-19 globally is the number of dead people divided by the number of confirmed cases in the countries where tests abound and health care is good. 

The following common situations will make the mortality appear higher 

• Tests running on short supply. Naturally, healthcare authorities will continue testing critically ill patients and stop testing people with light or no symptoms. The critically ill patients are more likely to die, artificially increasing the apparent mortality rate. 
• Political directives against testing. This appears to be the case of  the United States. Only 1 American in 1 million was tested by March 1. 
• diagnosing COVID-19 based on radiological findings because there are no tests. Only the most severe cases will show on a C-T scan. This certainly happened in Wuhan. 

With the above said, let's look at the numbers today and compare to last week. 

Here's the data from March 14, on which I based my 0.2% guess 

Country	Cases	Dead	Mortality %
Germany	5176	9	0.17
Sweeden	992	2	0.20
Denmark	864	2	0.23
Austria	800	1	0.13
Norway	1205	3	0.25
Total	9037	17	0.19

Here's the same data from today (March 19)

Country	Cases 19/3	Dead	Mortality %
Germany	13083	31	0.24
Sweden	1301	10	0.77
Denmark	1132	6	0.53
Austria	1843	5	0.27
Norway	1606	6	0.37
Total	18231	58	0.32

Germany and Austria stay reasonably close to my 0.2% estimate. 

What does that mean?

• the pandemics doesn't appear to be slowing down. 
• the effects of the quarantine, if it does work, don't show in the data. The quarantine prevents new infections, but, it hasn't been long enough for those newly infected people to be tested. 
• I stick to my guns. Now, my estimate is backed by larger numbers in these two countries. Thus, more solid.  The numbers of cases in the other countries are low suggesting large error bars and not enough tests.
• In a few days, once the hospitals get overwhelmed, there won't be enough tests and the apparent mortality will go up. 

Sweden, Denmark and Norway have gone up. I suspect that they are either out of tests or, due to stress in the medical system, there is no time to test mild cases. My own friend Teresia believes she is now sick with Coronavirus in Sweden and she doesn't even try to get tested. She drinks tea at home and doesn't even turn up the heat (even I am critical of that). Sending you best wishes! 

While in Germany and Austria, the number of detected cases has increased by a factor of 2.4 and 2.3,  Sweden, Denmark and Austria only went up by 30%.  The nature of the virus is the same. The population dynamic sufficiently similar. So, it could be that the pandemic is running its course just like in Germany and that they are out of test or that we start to see the effects of the quarantine.  Sweden stopped testing on large scale -- they are now only testing the cases that require hospitalization. Initially, I was hoping it showed the quarantine working, but it does not seem to be the case.

One can combine the data from the tables above into one table:

Country	Cases Mar 19	Cases Mar 14	Deaths	Mortality 19/3%	Cases 14/19
Germany	13083	5176	31	0.24	2.5
Sweden	1302	992	10	0.77	1.3
Denmark	1132	864	6	0.53	1.3
Austria	1843	800	5	0.27	2.3
Norway	1606	1205	6	0.37	1.3
Total	18231	9037	58	0.32	2.0

Now, let's look at the countries that showed high apparent mortality last week.

	Cases 19/3	Deaths	Mortality %
Italy	35713	2978	8.34
Iran	17361	1135	6.54
China	80928	3245	4.01
Spain	14769	638	4.32
France	9134	264	2.89
USA	9464	155	1.64
UK	2626	104	3.96
S Korea	8565	91	1.06
Diamond Princess	712	7	0.98

 Here's what the data looked like last week:

Country	Cases	Deaths	Mortality %
Italy	21157	1441	6.81
Iran	13838	724	5.23
China	80849	3119	3.86
Spain	6821	208	3.05
France	4499	91	2.02
USA	3045	60	1.97
UK	1140	21	1.84
S Korea	8162	75	0.92
Diamond Princess	696	7	1.01

The apparent mortality is essentially unchanged in China, South Korea and on the Diamond Princess boat. Here, the epidemics is over, or at least over for now. If the quarantine is the main reason the infection has stopped, then the quarantine will have to remain in place. A new wave of infection will start as soon as the country returns to life as normal. 

If the majority of the population has been infected because the quarantine has failed to stop the virus (note that the quarantine would still have flattened the peak of the epidemic, allowing the medical system to better serve the patients), then the country can return to life as normal. No significant COVID-19 deaths or new waves are to be expected. 

The apparent mortality has gone down in the US. That is, most likely, because they started to test more and more people with mild symptoms. The apparent mortality has gone up everywhere else, most likely due to strain in the medical system. 

Lombardy will soon be a good place to test this hypothesis. In the next few days, the epidemy there will stop. We will not see many new cases and people will heal. At that point, we will be able to calculate a lower bound for COVID-19 mortality by dividing the number of deaths to the total population. I guess at least half of the population would have been infected by this point, so this lower bound is correct within a factor of 2. Italy, in general, has a higher than usual flu mortality as I mentioned in my previous post. Thus, the COVID-19 mortality will also be higher, perhaps by the same factor.  

In conclusion, I believe the estimate I made last week is correct. The mortality for the coronavirus still hovers around 0.2%.