While France is going to begin the release from containment on May 11, a risk of the coronavirus returning is possible. Other countries have experienced this and raise fears of a new containment.
By confining the French, the government wanted to limit the number of people infected with the coronavirus as much as possible and thus limit the influx into hospitals. A strategy that seemed to pay off since the figures from hospitals are generally positive, because declining, for two weeks now. This same strategy nevertheless has a major drawback: it makes it very difficult to access the stage of collective immunity, this step which corresponds to the moment when a sufficient rate of the population would be immune, after having been contaminated for example, against Covid-19. Very recently, the Pasteur Institute, on the strength of a study, announced that by May 11, the date of the end of confinement, 6% of French people would be immunized, yet an estimated 60% the famous rate necessary for collective immunity, which would naturally stop the spread of the virus. Covid-19 will continue to circulate after May 11, and even if the rate of contagiousness of the virus has dropped since the start of the epidemic – from 3.4 to 0.6 today – the risk of a second epidemic wave will inevitably exist.
Until now, it was assumed that a person infected with the virus developed antibodies and was immune. Yes but … The infectious disease control center of South Korea, on the front line against the coronavirus long before Europe, published worrying news. Out of 7,329 cases of infected patients who had completed their quarantine and had tested negative, 163 (2.1%) were tested positive again. On average, the virus was found in these patients after 13.5 days. For one of them, the period between the end of quarantine and the return of the virus was 35 days. About a third of the patients tested positive a second time concerned young adults aged between 20 and 30 years. The explanation for this return of the virus is not yet certain according to scientists. These could be tests that did not work well, indicating that a patient was cured when he was not. Another explanation: the virus could “hide” in the body, in places where samples are not taken. He could then “hibernate” and return later. Other viruses have this behavior, such as Ebola which remains sexually transmitted to cured patients or even chickenpox which can return to adulthood after a child illness. The last possibility to explain this return of the virus, which would be the most frightening, would be that it could reactivate. According to Michael Kinch, director of the Center for Research Innovation in Biotechnology and Drug Discovery at Washington University in St Louis in the United States, it is not a reactivation strictly speaking which would occur but a new contamination. In the presence of another infected person, a cured patient would be infected again. The reason ? Patients who are too slightly affected would not create enough antibodies to be able to prevent a return of the coronavirus in the event of further exposure.
Data from South Korea has raised the question of whether a patient who has recovered from the coronavirus is automatically immunized. Mike Ryan, WHO executive director for health emergency management, said he was not sure if the antibodies in the blood would prevent further coronavirus. contamination. Covid-19 is the third coronavirus to spread on the planet after SARS and MRES. Studies have been performed for these two predecessors. Being infected with SARS would give the patient about two years of immunity. For the MRES it would be three years. These two studies tell us that immunity is possible … but not unlimited. Scientists believe that the strength of the disease could induce the power of immunity. Patients who have developed mild symptoms would therefore have a reduced amount of antibody. Thus, a quarter of 175 Chinese patients who had little or no symptoms developed a very weak immune response.
In China, while the containment measures have been lifted in Wuhan, the cradle of the coronavirus, the health authorities are being very vigilant after concerns arising from new contaminations recorded in Heilongjiang province, near the Russian border. The provincial capital, Harbin, was even forced to re-establish control measures in certain districts. These new cases are the result of so-called imported contaminations, because now the most important epidemic foci are located outside of China. And many in Russia. However, within a few days, “local” cases were reported. The figures are very low: 10 cases one day, 12 another. But the existence of these cases raises questions. Are they the result of contamination via imported cases or are there still outbreaks in China, ready to catch fire after the reopening of the country?
City-State, Singapore had initially succeeded in containing the spread of the virus thanks to a very strict strategy of control and tracing of the contacts with the infected people. On April 8, there were only 142 new cases that day and 6 deaths since the start of the epidemic. But everything has been racing since April 15. The health authorities of the financial center of Southeast Asia announced Monday, April 20, 1426 new cases of people contaminated by Covid-19. The number of new cases has jumped across the country since test campaigns were launched in overcrowded homes where migrant workers live, often in unsanitary conditions. The country’s prime minister had warned that the number of migrant workers infected with the virus was likely to increase sharply as test campaigns were rolled out. As a result, the authorities have ordered quarantine for tens of thousands of workers and moved many of them to less dense housing, to avoid further spread. And Singapore, which had already closed its borders to non-residents, resolved to temporarily close schools and non-essential businesses. In short, confinement after the hour.
Before the Senate on April 15, Jean-François Delfraissy, the president of the Scientific Council, predicted between 10,000 and 15,000 new contaminations per day once the deconfinement was implemented in France. In recent days, the daily reports of the Ministry of Health show 400 to 2,500 new daily contaminations … Hence the need for a very studied containment exit plan, which the government must make public at the end of April. The National Institute of Health and Medical Research (Inserm), in a study posted online on April 12, insisted that it will be necessary to maintain social distancing after the end of confinement. “The lifting of containment without exit strategy would cause a second wave overwhelming the health system,” warned the institute, especially that for the time being and not before “mid-2021”, according to Prime Minister Edouard Philippe, no vaccine against Covid-19 has not been found and marketed. And bad news, for now, experts believe that only a vaccine will really do away with the coronavirus.
In an interview with the Washingon Post, the director of the American center for infectious diseases said he was very worried about a return of the Covid-19 this winter. He believes that a cocktail between the seasonal flu and the coronavirus would be explosive. Especially since the containment had another unexpected effect: it ended the seasonal flu with about 1 and a half months in advance. However, it is the end of the seasonal flu in the spring which allows epidemiological models to anticipate the next wave. And therefore to design suitable vaccines, including protection against “current” viruses. Indeed, if it is called in the year “flu”, this disease is indeed caused each year by one or more different viruses. All the scientists’ work is to estimate in the spring which viruses will be present six months later and to include them in the annual vaccine. In the absence of reliable information, the vaccine could be much less effective this year because it may not target all the circulating viruses. The congestion in the healthcare system in the United States caused by a severe flu and a Covid-19 returning would be much worse than what was known between March and April.
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