What about the measures being considered as the government organizes a gradual lifting of restrictions on May 11? What do we know about the contagiousness of children? What are the issues related to testing? What about future changes in Covid-19? Will it last through the summer? And the second wave? Update on current scientific knowledge.
The government announced a general reintegration on May 11, with a deconfinement strategy that confirms that the priority is the preservation of profits, not the health of the population. A second wave of contagion seems inevitable according to some specialists, and nothing at this moment seems to indicate that its progression would slow down once winter is over (according to Donald Trump). Another concern expressed would be the mutation rate of SARS-COV-2, which predicts the emergence of a more virulent strain than the one we are currently experiencing. However, the link between the virus’s mutation (rapid or not) and its virulence is not proven and does not necessarily make sense if we refer to the process of natural selection in the theory of evolution.
Related reading : Portage salarial: a silent revolution in the world of work
What about the exit strategy announced by Macron?
The number of new infections in France seems to be decreasing; we have surpassed the peak of the epidemic since the week of April 6. Macron announced an exit for May 11.
First, it should be noted that the dismantling will occur earlier for many workers, as it is no longer about essential activities, but those that can operate under barrier gestures. It is safe to say that work in many businesses will resume as early as the week of April 20, with its share of infected individuals, either at the workplace or in public transport. We refer here to the general statement from UCL [1].
Further reading : What is the role of a land expert?
Next, there is the question of protective equipment: will there be enough on May 11, and now for the sectors that will take over? This can be seriously questioned when access to equipment is still under pressure in many hospitals.
The reopening of nurseries, schools, colleges, and secondary schools caught everyone off guard. It is acknowledged that children are asymptomatic in the majority of cases, so the virus is not dangerous for them (fewer than 10 children under 15 have died from coronavirus worldwide since the beginning of the epidemic), although it spreads very quickly among them, as it is difficult to enforce barrier gestures.
The reopening of schools
The ongoing question is whether they are contagious, and this question arises worldwide for all asymptomatic carriers. Professor Raoult reportedly influenced Macron’s decision to reopen schools [2] (let’s remember that Macron visited him on April 10). Nevertheless, his study on the subject states only two things: that children are asymptomatic, and their viral load is not higher than that of adults, which does not mean it is lower!
Thus, children could massively catch the virus in schools and transmit it to their parents, grandparents, etc. Once again, Professor Raoult favored communication, without the slightest scientific basis, with potentially dramatic consequences. And Macron is happy to find pseudo-scientific arguments to support the current decision, whose sole purpose is to send parents back to work.
While waiting to learn more about the contagiousness of children and symptoms of asymptomatic individuals in general, the principle of precaution should prevail: schools should have remained closed, which almost all scientists recommended. Furthermore, barrier gestures will need to be respected within institutions, which is more than complex and will probably not be ready by May 11.
Long-term confinement of the elderly
Constraints will remain for those who are “at risk.” But we do not know, for example, at what age it will be imposed: 70, 65, 60? This will affect older workers. The Scientific Council estimates that 18 million people are at risk [3], which is therefore not a small issue.
The thorny issue of testing and screening
Macron announced testing only for symptomatic individuals. This decision, of course, is guided by the lack of testing capacity. In any case, there is a scientific consensus that testing symptomatic individuals is almost uninteresting because we already know they are sick; the tests only confirm whether it is Covid-19.
It is essential to focus on screening individuals who have been in contact with the infected person (family, colleagues, neighbors, etc.) to determine if they are sick before symptoms appear; this saves valuable time in controlling the spread of the epidemic. The question also arises about mass testing certain populations: caregivers, children, populations in a “cluster” area, or even anyone who wants to be tested.
However, the government is considering a contact tracing application that allows for digital screening surveys, and thus faster. This seems incompatible with testing only symptomatic individuals. But above all, this raises a number of questions regarding both effectiveness and the cost in terms of individual freedoms [4], and we will return to this topic in a future article.
**
Macron discussed serological tests, explaining that only a small part of the population will be infected and thus vaccinated, which seems to suggest that these tests are unnecessary. The Scientific Council estimates that a portion of the vaccination “may be around 10-15%” but based on tests conducted in Oise and Grand Est, areas that have been severely affected. Therefore, we are probably very far, on a national scale, from the approximately 60% needed to achieve herd immunity.
How long are we immune?
Furthermore, remember that the duration of immunity today is unknown, but probably on the order of a few months. The question remains to determine the proportion of asymptomatic individuals. France will therefore not do so, for obscure reasons, but Germany is in any case in the process of conducting studies on the subject. Another importance of these serological tests would be to “use” vaccinated populations for tasks with patients, which could, in particular, be of interest for caregivers and personal data in nursing homes. There is also no announcement.
Macron said nothing about chloroquine, except that all indications have been examined, which is compatible with, for example, the Inserm Discovery study, which tests 5 molecules.
A virulent virus may not be more dangerous
In relation to the questions surrounding the second wave, fears about possible mutations of the virus are sometimes expressed. The SARS-COV-2 coronavirus, like any other virus, mutates very quickly. However, it should be noted that for viruses, the mutation rate of SARS-COV-2 seems to be quite low: an average of 2 mutations per month [5]. But the question is not to be mistaken: the question is not whether a mutation that makes the virus virulent can exist (the answer is trivially yes), but whether such a mutation (virulent) has a real chance of being the winner of the natural selection process.
Indeed, the resources available for the coronavirus — in this case, the global human population — are limited, and natural selection thus pushes the virus to adapt to survive. In other words, a mutation of the virus that would make it unable to spread, infect, or reproduce in new individuals would disappear as soon as the first infected case recovers. On the contrary: for a mutation to have the best chance of adjusting, and for its frequency in the virus population to increase, it is necessary that the mutation provides what is called a selective advantage: better infection, faster replication, etc.
By approaching the question this way, it is better to understand why the virulence of a virus, defined as its ability to make the host sick; or even lead to death, is never an advantage for the virus itself. A sick host moves less, will be less in contact with other potential hosts and — in case of concern — may even end up in cellular isolation in an intensive care unit. The exact opposite of a successful adjustment.
A successful adaptation, for a virus, is on the contrary the least virulent possible, to remain unnoticed and be able to replicate quietly and spread. This is one of the great “advantages” of SARS-COV-2. Not all individuals infected with the virus necessarily have symptoms, which affects its spread in the population.
The
virulence is, for a virus, an undesirable secondary consequence. When it increases, it is because it is linked to another aspect of the virus that, in turn, is selected by evolution — just as HIV, by replicating in the organism, weakens the immune defense.
However, the ongoing mutations of the SARS-COV-2 coronavirus currently have no reason to lead to increased virulence or lethality: its “success” is so far remarkable and very few obstacles stand in its way. Virologists and epidemiologists currently consider that a “new more virulent strain” is unlikely to manifest in the near future. If evolution and selection were to occur in the short term, then it is necessary to expect that they would push for a better rate of (the average number of people infected by the virus in a day). Indeed, the coronavirus is still far from infecting a significant portion of the global population and, in a sense, is still swimming in a pool of potential hosts. A mutation that would allow it to spread would, therefore, need to provide a real selective advantage.
A summer armistice from the Corona virus?
On the other side of the Atlantic, Donald Trump stated several weeks ago that the virus could not survive in summer, supported by a handful of Chinese scientists, and imitating the rumor that the virus does not withstand heat. Would the virus actually disappear in summer, and what are the elements behind this hypothesis?
Antoine Flahault, director of the Global Health Institute in Geneva, and infectious disease specialist Anne-Claude Crémieux stated in February that it is not possible to predict whether the virus will be affected by seasons like other known viruses [6].
For other viruses, the reasons for this seasonality are multiple. First, they survive better on hands and inert surfaces in a cold and dry environment, as advanced by Olivier Schwartz, Director of the Virus and Immunity Unit at the Pasteur Institute, and Frédéric Tangy, head of the Viral Genomics and Immunization Laboratory at the Pasteur Institute. Jeremy Rossman, a virology professor at the University of Kent in the UK, adds that the duration of sunlight in winter causes a deficiency in vitamin D and melatonin, and that the dry air during this period reduces the effectiveness of nasal mucus, weakening the immune system and making it more permeable to viruses and infections.
Anne-Marie Moulin (researcher at the SPHERE laboratory of CNRS) explains that these are just reflections, by analogy with known viruses, without retrospect on the behavior of Covid-19. It also seems that other parameters, such as wind, significantly affect the spread on a large scale, complicating the analysis of the seasonal behavior of viruses and infections. Scott Dowell (epidemiologist leading the development and monitoring of vaccines for the Bill & Melinda Gates Foundation) indicates that the seasonality of viruses is not really well understood and is an important research axis in the field of epidemiology.
According to Covid-19, a study from Beihang University in China on March 3, 2020, highlighted that a warm and humid environment accelerates the evaporation of micro-droplets responsible for the spread of Covid-19, which would significantly slow down transmission [7]. David Heymann from the London School of Hygiene and Tropical Medicine relativizes that the evidence specific to the pandemic we are experiencing is not sufficient to draw conclusions about its seasonality. Furthermore, tests for the coronavirus indicate a relatively high resistance to heat compared to other viruses [8]. The authors also emphasize that infections in Singapore, Australia, and the African continent clearly show that the virus spreads regardless of the climate. When both hemispheres of the globe are affected, one cannot expect a significant seasonal effect on the reproduction rate.
In conclusion, it is difficult to think that summer will slow down the virus, and various scientific interventions indicate that there has been no major epidemic or pandemic that has ceased to change with the seasons [9]. Letting vigilance regarding the virus’s health under the pretext that summer heat will soften its spread would take a risk that could have disastrous consequences.
And the second wave?
On January 23, China declared a reduction in the population after the catastrophic acceleration of the Coronavirus epidemic (Covid-19, SRAS-COV-2), particularly in the province of Wuhan, considered the first infectious hotspot. Two months later, on March 25, deconfinement began, except for the province of Wuhan, which had to wait until April 6. The press massively reports the return to normal activity of the population, quickly astonished across the territory. However, a new increase in the number of cases (55 new cases in the province of Henan ten north of Wuhan) causes the Chinese government to fear the arrival of a second wave of infection for which their healthcare system would not be prepared.
Elsewhere in Southeast Asia, where the epidemic also seemed to have been contained, a new surge in cases has already led Malaysia and Hong Kong to relaunch a fight plan. This reaction seems to conform to WHO recommendations that this region of the world “conducts a violent fight against the epidemic” [10] to avoid the collapse of its healthcare systems.
On site, experts such as Zhong Nanshan, head of the Chinese expert team on Covid-19, estimate that it may be attributed to European travelers or the return of expatriates from involved countries. They assure that the epidemic will be over in April and that the epicenter of the pandemic is already in the United States, where Covid-19 is wreaking havoc.
However, other events may be responsible for this rebound of the epidemic. A religious gathering of 16,000 people in Kuala Lumpur may have led to the emergence of a new infectious epidemic and the resumption of infection, especially in Malaysia. This new wave of infection also calls into question the low number of patients reported by Myanmar and Laos, bordering countries to Malaysia, and thus the reliability of these figures. However, the reason for the rebound in the number of infections is rather the reduced percentage of these populations immunized against the virus or due to poor-quality tests that may have produced false positives [11].
Other epidemiological statements seem more relevant [12].
Benjamin Cowling, an epidemiologist at the University of Hong Kong, considers that the second wave of contagion is “totally inevitable” and speaks in particular of “silent spread,” referring to infected but asymptomatic individuals released en masse after confinement. Ma Jin, director of the school at Jiaotong University in Shanghai, announces that “the fight against the coronavirus will be a long-term struggle.”
Matthieu Revest from the University of Rennes-I believes that a second wave of infection is inevitable, but it will be less intense than the one we are currently experiencing. Antoine Flahault and François Bricaire, head of the Infectious Diseases Department at Salpêtrière Hospital, indicate, for example, that the Spanish flu caused 50 million deaths in three waves over two years between 1918 and 1919.
Numerical simulations already predict a massive second wave of contamination by the end of August in China if measures are not taken. On the other hand, if confinement is continued until the end of April, this return of the epidemic could be postponed by two months. Although these models have their limitations, they seem to indicate that confinement, and health measures in general, should not be interrupted with the risk of provoking a second wave of contamination that could be very problematic for our already overstretched healthcare systems.
Let us conclude with this recent study from Inserm [13] on different scenarios for exiting confinement in Île-de-France. To delay a new lockdown until January 2021, contact tracing should be relatively effective, alternating between “light” measures (school closures, reduction of elderly people, preferred teleworking) and “medium-sized” measures (closure of half-year) of non-essential activities, etc. Suffice it to say that we are far from such a strategy.
UCL Scientific Working Group, April 19, 2020
[1] UCL statement, “Macron prepares a cut for employers,” April 14, 2020.
[2] Marcelo Wesfreid and Tristan Vey, “Reopening schools: Did Emmanuel Macron influence by a study by Didier Raoult?”, Le Figaro, April 14, 2020.
[3] “Coronavirus: 18 million French people at risk remain restricted after May 11,” Les Échos, April 15, 2020.
[4] “Apps, drones… the health alibi for general surveillance,” Alternative Libertarian, May 2020.
[5] against every 6 hours for viruses of the same family: Nicolas Martin and the team of La Méthode scientifique, “Coronavirus: continuous mutation,” France Culture, March 26, 2020.
[6] “Will the Covid-19 coronavirus epidemic disappear in April due to heat, as Donald Trump claims?”, France Télévision, February 12, 2020.
[7] Decrease in the reproduction rate R0, the average number of people infected by the disease, by 48% between March and July.
[8] The virus only deteriorates at 56 °C for 30 minutes and at 65 °C in about 10 minutes.
[9] Recent example: SARS 2002. The epidemic was avoided by banning the use of civet (reservoir species for this virus) and not waiting for summer.
[10] “Coronavirus: new wave of infection in countries that thought the epidemic was under control,” Europe 1 with AFP, March 22, 2020.
[11] Coralie Lemke, “Can we be infected twice by the Covid-19 coronavirus?”, Science et avenir, March 3, 2020.
[12] UCL Scientific Working Group, “Pathways for herd immunity: inclusion vs laissez-faire,” April 12, 2020.
[13] Laura Di Domenico, Giulia Pullano, Chiara E. Sabbatini, Pierre-Yves Boëlle, and Vittoria Colizza, “Expected impact of lockdown in Île-de-France and possible exit strategies,” Inserm, April 12, 2020.
Source: votrejournal.net