PCR: I have been in communication with an experienced virologist in Belgium who worked for many years in the US on coronaviruses. Watching the inaction of the Belgium government, he has sent this letter to the country’s authorities.
Having led a small team of researchers for a dozen years in the United States on human coronaviruses, and in particular on SARS-CoV, I would like to share my perspective on the particular challenge that this new coronavirus poses for the population.
The new coronavirus is now called COVID-19 by the W.H.O., and SARS-CoV-2 by virologists to emphasize its genetic proximity to SARS-CoV. The commonalities and differences between the two, the lessons that can be learned from epidemics and the comparison with the flu virus shed light on the choices to be made for public health.
In addition, both the SARS epidemic and that caused in 2012 by another similar coronavirus, MERS-CoV, led only to a limited number of infected individuals and fatalities: SARS-CoV, 8,098 probable cases and 774 fatalities (9.6%); MERS-CoV, 2,492 probable cases and 858 fatalities (34.4%). In comparison, the influenza virus infects tens of millions each year and causes tens of thousands of fatalities worldwide (death rate ~ 0.1%).
We must recognize an essential difference between the flu with which we are all familiar and which causes severe complications only in people with weak immune systems (~ 0.2% of cases), and the atypical pneumonias at the center of the syndrome affecting individuals infected with SARS-CoV, MERS-CoV or SARS-CoV-2, i.e. the proportion of severe cases (~ 16% of cases for SARS-CoV-2, WHO February 10).
We have been officially in a flu epidemic for two weeks in Belgium, having passed the threshold of 132 visits to a doctor for 100,000 inhabitants. Surveillance of a fraction of influenza cases indicates a mix of different strains of the influenza virus, but in a fraction of these cases the virus causing the symptoms remains unidentified. We must determine in the coming months if this fraction contains cases due to COVID-19.
Each year, the flu virus typically infects between 2 and 8% of Belgians. A rate of 5% corresponds to 550,000 infections and with 0.2% of them presenting complications requiring hospitalization, this amounts to 1,100 hospitalizations for the country in this case.
There are 6.4 general purpose hospital beds per 1,000 inhabitants in Belgium and with an occupancy rate that fluctuates around 80%, there remains an average of 1.28 beds per 1,000 inhabitants available, more than enough to accommodate flu cases with complications even when 10% of the population suffers from the flu. On the other hand, the complication rate requiring hospitalization is 16% for cases of symptomatic infection with these new coronaviruses, thus eighty times that of the flu!
Relatively few cases are enough for the hospital system to be overwhelmed: just ten cases of infection by COVID-19 per 1,000 inhabitants (1% of the population) would require 1.6 hospital beds per 1,000 inhabitants, at the threshold of a critical situation.
In cases requiring hospitalization, SARS affects more than the respiratory system, it is a systemic disease involving several organs: the coronavirus damages the lungs, intestines, small blood vessels and the central nervous system.
Coronaviruses antagonize the interferon system, our first line of defense against viruses, which allows them to replicate without brake and also leads to an abnormal innate humoral immune response (these two factors explaining long incubation periods), with excessive production of some cytokines; death occurs in half of these severe cases, due to respiratory failure or multi-organ failure caused by these cytokines.
A cross-check of sources (scientific publications, press and internet) indicates that today February 17 there are more than 800,000 probable cases of COVID-19 in China and well over 50,000 fatalities, figures much higher than those published by the Chinese government (71,335 cases and 1,775 fatalities). The city of Wuhan has 38 crematoriums which have been operating 24 hours a day since February 1 and collectively can incinerate 1,200 corpses per day.
The 2002-2003 SARS epidemic was controlled by elementary public health measures which consist of isolating infected patients, identifying the persons with whom each patient has been in contact, and monitoring or isolating these contacts in turn.
This epidemic almost escaped the control of the authorities on several occasions, in particular in Hong Kong and Toronto, because a large part of the medical personnel were also infected with this coronavirus.
The relatively small number of cases due to SARS-CoV has made it possible for basic public health measures to come to grips with this epidemic, and it is clearly no longer possible to identify and isolate the contacts of patients infected with COVID-19 when the number of patients is in the hundreds of thousands and the majority of them cannot be treated.
In Belgium, we are still at a stage where public health measures can make a difference and I am surprised at the timidity of the announcements made by the competent authorities in this regard; the message seems to be “we are ready”, which sounds a little hollow given the figures given above.
The key factor in epidemiology is R0, the basic reproduction number of the virus. A value of 2 indicates that an average patient infects two others. Any figure greater than 1 leads to an epidemic that spreads exponentially in a naive population. We are all completely immunologically naive for this coronavirus, while we are not naive for the flu.
Different authors calculate values between 2.2 and 3 for the R0 of COVID-19, values similar to those for influenza viruses, and may be influenced downward by quarantine procedures. In fact, a more recent study indicates that in the absence of quarantine, the R0 of COVID-19 is between 4.7 and 6.6; and yet another puts it at 7.
A complication in the transmission of COVID-19 compared to SARS-CoV and MERS-CoV is that apparently it can occur even before symptoms appear. Japanese researchers calculate that half of the infections take place while the patient is still asymptomatic, while American researchers think that the proportion is lower, 10-20%.
This property, and the relatively long incubation time of coronaviruses before the onset of symptoms, makes the task of identifying contacts and isolating them much more difficult (incubation, typically 1 to 14 days but longer times are also observed; for influenza it is 1 to 4 days).
The doubling time of the number of infected individuals is estimated at 6.4 days by some, at 5 days, by others, and only 2.4 days in the absence of quarantine measures. So from a case today, we would arrive at 131,072 infected in 85 days in the least favorable scenario with quarantine measures, which brings us to the beginning of May. In the absence of quarantine measures, however, we top a million cases in 48 days.
Another complication which renders the usual public health measures ineffective are the “super-spreaders” who for misunderstood reasons are capable of infecting a large number of individuals; if they appear early, they can change the dynamics.
It is not possible to predict the number of cases in Belgium that will be caused by COVID-19, but everything must be done to minimize its transmission and stay below 10 symptomatic cases per 1,000 population, i.e. 110,000 cases for Belgium.
I would like to suggest several public health measures that are more aggressive than those proposed to date. The SPF health website recommends: “if you are sick and if you have been to China recently or if someone close to you is sick and has gone to China, call your general practitioner to report your trip and your symptoms. Do not go to his waiting room or to the emergency room. ”
Excellent suggestion that should simply be extended to anyone with temperature or other flu or enteric symptoms (diarrhea). These people, as well as those living under the same roof, should remain in isolation until the infectious agent has been identified in each case, and longer if necessary depending on the outcome.
We should remember that multiple infections with different viruses are possible and that the COVID-19 may not be immediately detectable when the patient is already very ill. For example, the virus could not be detected until a week after the hospital admission of the ophthalmologist who launched the alert in China on this epidemic. This could be attributed to defective detection kits and/or to a virus that replicates more efficiently in the lungs than the rest of the respiratory tract; it should be noted that even for CDC-produced kits, a substantial proportion of them were found to be defective.
In Hong Kong in 2003, a hospital well prepared for infectious disease had only one medical staff infected with SARS-CoV, while in another less well-prepared hospital, the admission of only one patient led to 136 cases, mostly medical staff. In 2003 in Toronto, 257 people were infected in several hospitals before the spread of the virus was controlled, but protective measures were lifted too quickly, resulting in a second wave of infection a month later!
We should remember that convalescent patients can sometimes be still contagious, especially through their stools, and that contaminated material can remain infectious for weeks. Despite all this knowledge, over 1,300 medical staff were reported to be infected in Wuhan as of today.
It is critical to keep medical personnel uninfected, both so that they can continue to treat and to prevent them from becoming vectors of spread themselves. As asymptomatic transmission of COVID-19 seems likely, all patients, whatever the reason for their presentation, and all hospital staff, whatever their function, should all be considered as potentially contagious and treated as such.
A video was able to capture several transmissions of COVID-19 in a market in China and in one case it was enough to have an interaction of 15 seconds between two individuals wearing no mask and separated by a display of vegetables for the contamination to take place. In another market, the shortest transmission event was a 50-second interaction. While SARS-CoV transmission involved relatively large droplet and short distance, the evidence indicates that COVID-19 can be transmitted through aerosol.
Which brings me to my second suggestion. A place like a hospital with many and varied human contacts promotes the spread of viruses, this is certainly one of the lessons of coronavirus epidemics, including this one. A simple N95 type mask correctly positioned on a beardless face very effectively protects against the risk of infection and significantly limits transmission by infected people.
Wearing such a mask at work, as well as eye protection, is a constraint and tiring, but their immediate adoption by hospital staff is the surest way to limit the circulation of COVID-19 in Belgium and to protect those on the front lines to maintain the health of the population. Experience shows (MERS-CoV, in South Korea) that even when the nursing staff was adequately protected by their N95 mask, it was the auxiliary staff such as the receptionists who were infected and who contributed to the dissemination of the disease.
In all major respiratory epidemics, sooner or later we come to the situation where all hospital staff wear an adequate mask. Let’s be smart and put on these masks as soon as possible, let’s not wait for the first cases before acting!
Finally, we should be transparent with the Belgian public about the reality of the particular risk posed by COVID-19 and educate them on how they can best protect themselves and others. For example, the friendly gesture of kissing colleagues and friends can only encourage the spread of such a virus.
Instead of claiming, as a video on a mainstream news website does, that packages from China are safe, an unscientific and erroneous claim, it is more useful to represent the real situation: the risk is really very weak, but it cannot be overlooked given the possible consequences of contamination.
We must also give people the tools they need to protect themselves. For example, how do you clean a package, or a coat on which someone sneezed on in the tram? It turns out that coronaviruses are relatively fragile from a physicochemical point of view and can be inactivated by common household products, such as bleach, detergents and soaps in general, alcohol 70 %, even dry cleaning products, or a temperature above 60 °C.
And we must provide the public with a phone number that anyone with a symptom can contact to arrange for the testing of samples. Attending events with large crowds should also be discouraged until we have a better understanding of transmission dynamics in our country. There needs to be a very visible public information campaign as soon as possible.
Let’s all work together to eliminate this virus and stay healthy!
Source
***
The new coronavirus, are the proposed public health measures adequate?
Marc G. Wathelet: What to do in Belgium about the new coronavirus epidemic that is spreading catastrophically in China? The new coronavirus, are the proposed public health measures adequate?
Having led a small team of researchers for a dozen years in the United States on human coronaviruses, and in particular on SARS-CoV, I would like to share my perspective on the particular challenge that this new coronavirus poses for the population.
The new coronavirus is now called COVID-19 by the W.H.O., and SARS-CoV-2 by virologists to emphasize its genetic proximity to SARS-CoV. The commonalities and differences between the two, the lessons that can be learned from epidemics and the comparison with the flu virus shed light on the choices to be made for public health.
In addition, both the SARS epidemic and that caused in 2012 by another similar coronavirus, MERS-CoV, led only to a limited number of infected individuals and fatalities: SARS-CoV, 8,098 probable cases and 774 fatalities (9.6%); MERS-CoV, 2,492 probable cases and 858 fatalities (34.4%). In comparison, the influenza virus infects tens of millions each year and causes tens of thousands of fatalities worldwide (death rate ~ 0.1%).
We must recognize an essential difference between the flu with which we are all familiar and which causes severe complications only in people with weak immune systems (~ 0.2% of cases), and the atypical pneumonias at the center of the syndrome affecting individuals infected with SARS-CoV, MERS-CoV or SARS-CoV-2, i.e. the proportion of severe cases (~ 16% of cases for SARS-CoV-2, WHO February 10).
We have been officially in a flu epidemic for two weeks in Belgium, having passed the threshold of 132 visits to a doctor for 100,000 inhabitants. Surveillance of a fraction of influenza cases indicates a mix of different strains of the influenza virus, but in a fraction of these cases the virus causing the symptoms remains unidentified. We must determine in the coming months if this fraction contains cases due to COVID-19.
Each year, the flu virus typically infects between 2 and 8% of Belgians. A rate of 5% corresponds to 550,000 infections and with 0.2% of them presenting complications requiring hospitalization, this amounts to 1,100 hospitalizations for the country in this case.
There are 6.4 general purpose hospital beds per 1,000 inhabitants in Belgium and with an occupancy rate that fluctuates around 80%, there remains an average of 1.28 beds per 1,000 inhabitants available, more than enough to accommodate flu cases with complications even when 10% of the population suffers from the flu. On the other hand, the complication rate requiring hospitalization is 16% for cases of symptomatic infection with these new coronaviruses, thus eighty times that of the flu!
Relatively few cases are enough for the hospital system to be overwhelmed: just ten cases of infection by COVID-19 per 1,000 inhabitants (1% of the population) would require 1.6 hospital beds per 1,000 inhabitants, at the threshold of a critical situation.
In cases requiring hospitalization, SARS affects more than the respiratory system, it is a systemic disease involving several organs: the coronavirus damages the lungs, intestines, small blood vessels and the central nervous system.
Coronaviruses antagonize the interferon system, our first line of defense against viruses, which allows them to replicate without brake and also leads to an abnormal innate humoral immune response (these two factors explaining long incubation periods), with excessive production of some cytokines; death occurs in half of these severe cases, due to respiratory failure or multi-organ failure caused by these cytokines.
A cross-check of sources (scientific publications, press and internet) indicates that today February 17 there are more than 800,000 probable cases of COVID-19 in China and well over 50,000 fatalities, figures much higher than those published by the Chinese government (71,335 cases and 1,775 fatalities). The city of Wuhan has 38 crematoriums which have been operating 24 hours a day since February 1 and collectively can incinerate 1,200 corpses per day.
The 2002-2003 SARS epidemic was controlled by elementary public health measures which consist of isolating infected patients, identifying the persons with whom each patient has been in contact, and monitoring or isolating these contacts in turn.
This epidemic almost escaped the control of the authorities on several occasions, in particular in Hong Kong and Toronto, because a large part of the medical personnel were also infected with this coronavirus.
The relatively small number of cases due to SARS-CoV has made it possible for basic public health measures to come to grips with this epidemic, and it is clearly no longer possible to identify and isolate the contacts of patients infected with COVID-19 when the number of patients is in the hundreds of thousands and the majority of them cannot be treated.
In Belgium, we are still at a stage where public health measures can make a difference and I am surprised at the timidity of the announcements made by the competent authorities in this regard; the message seems to be “we are ready”, which sounds a little hollow given the figures given above.
The key factor in epidemiology is R0, the basic reproduction number of the virus. A value of 2 indicates that an average patient infects two others. Any figure greater than 1 leads to an epidemic that spreads exponentially in a naive population. We are all completely immunologically naive for this coronavirus, while we are not naive for the flu.
Different authors calculate values between 2.2 and 3 for the R0 of COVID-19, values similar to those for influenza viruses, and may be influenced downward by quarantine procedures. In fact, a more recent study indicates that in the absence of quarantine, the R0 of COVID-19 is between 4.7 and 6.6; and yet another puts it at 7.
A complication in the transmission of COVID-19 compared to SARS-CoV and MERS-CoV is that apparently it can occur even before symptoms appear. Japanese researchers calculate that half of the infections take place while the patient is still asymptomatic, while American researchers think that the proportion is lower, 10-20%.
This property, and the relatively long incubation time of coronaviruses before the onset of symptoms, makes the task of identifying contacts and isolating them much more difficult (incubation, typically 1 to 14 days but longer times are also observed; for influenza it is 1 to 4 days).
The doubling time of the number of infected individuals is estimated at 6.4 days by some, at 5 days, by others, and only 2.4 days in the absence of quarantine measures. So from a case today, we would arrive at 131,072 infected in 85 days in the least favorable scenario with quarantine measures, which brings us to the beginning of May. In the absence of quarantine measures, however, we top a million cases in 48 days.
Another complication which renders the usual public health measures ineffective are the “super-spreaders” who for misunderstood reasons are capable of infecting a large number of individuals; if they appear early, they can change the dynamics.
It is not possible to predict the number of cases in Belgium that will be caused by COVID-19, but everything must be done to minimize its transmission and stay below 10 symptomatic cases per 1,000 population, i.e. 110,000 cases for Belgium.
I would like to suggest several public health measures that are more aggressive than those proposed to date. The SPF health website recommends: “if you are sick and if you have been to China recently or if someone close to you is sick and has gone to China, call your general practitioner to report your trip and your symptoms. Do not go to his waiting room or to the emergency room. ”
Excellent suggestion that should simply be extended to anyone with temperature or other flu or enteric symptoms (diarrhea). These people, as well as those living under the same roof, should remain in isolation until the infectious agent has been identified in each case, and longer if necessary depending on the outcome.
We should remember that multiple infections with different viruses are possible and that the COVID-19 may not be immediately detectable when the patient is already very ill. For example, the virus could not be detected until a week after the hospital admission of the ophthalmologist who launched the alert in China on this epidemic. This could be attributed to defective detection kits and/or to a virus that replicates more efficiently in the lungs than the rest of the respiratory tract; it should be noted that even for CDC-produced kits, a substantial proportion of them were found to be defective.
In Hong Kong in 2003, a hospital well prepared for infectious disease had only one medical staff infected with SARS-CoV, while in another less well-prepared hospital, the admission of only one patient led to 136 cases, mostly medical staff. In 2003 in Toronto, 257 people were infected in several hospitals before the spread of the virus was controlled, but protective measures were lifted too quickly, resulting in a second wave of infection a month later!
We should remember that convalescent patients can sometimes be still contagious, especially through their stools, and that contaminated material can remain infectious for weeks. Despite all this knowledge, over 1,300 medical staff were reported to be infected in Wuhan as of today.
It is critical to keep medical personnel uninfected, both so that they can continue to treat and to prevent them from becoming vectors of spread themselves. As asymptomatic transmission of COVID-19 seems likely, all patients, whatever the reason for their presentation, and all hospital staff, whatever their function, should all be considered as potentially contagious and treated as such.
A video was able to capture several transmissions of COVID-19 in a market in China and in one case it was enough to have an interaction of 15 seconds between two individuals wearing no mask and separated by a display of vegetables for the contamination to take place. In another market, the shortest transmission event was a 50-second interaction. While SARS-CoV transmission involved relatively large droplet and short distance, the evidence indicates that COVID-19 can be transmitted through aerosol.
Which brings me to my second suggestion. A place like a hospital with many and varied human contacts promotes the spread of viruses, this is certainly one of the lessons of coronavirus epidemics, including this one. A simple N95 type mask correctly positioned on a beardless face very effectively protects against the risk of infection and significantly limits transmission by infected people.
Wearing such a mask at work, as well as eye protection, is a constraint and tiring, but their immediate adoption by hospital staff is the surest way to limit the circulation of COVID-19 in Belgium and to protect those on the front lines to maintain the health of the population. Experience shows (MERS-CoV, in South Korea) that even when the nursing staff was adequately protected by their N95 mask, it was the auxiliary staff such as the receptionists who were infected and who contributed to the dissemination of the disease.
In all major respiratory epidemics, sooner or later we come to the situation where all hospital staff wear an adequate mask. Let’s be smart and put on these masks as soon as possible, let’s not wait for the first cases before acting!
Finally, we should be transparent with the Belgian public about the reality of the particular risk posed by COVID-19 and educate them on how they can best protect themselves and others. For example, the friendly gesture of kissing colleagues and friends can only encourage the spread of such a virus.
Instead of claiming, as a video on a mainstream news website does, that packages from China are safe, an unscientific and erroneous claim, it is more useful to represent the real situation: the risk is really very weak, but it cannot be overlooked given the possible consequences of contamination.
We must also give people the tools they need to protect themselves. For example, how do you clean a package, or a coat on which someone sneezed on in the tram? It turns out that coronaviruses are relatively fragile from a physicochemical point of view and can be inactivated by common household products, such as bleach, detergents and soaps in general, alcohol 70 %, even dry cleaning products, or a temperature above 60 °C.
And we must provide the public with a phone number that anyone with a symptom can contact to arrange for the testing of samples. Attending events with large crowds should also be discouraged until we have a better understanding of transmission dynamics in our country. There needs to be a very visible public information campaign as soon as possible.
Let’s all work together to eliminate this virus and stay healthy!
Source
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