Foretells whether the current epidemic another, much larger?

Предвещает ли нынешняя эпидемия другую, гораздо более масштабную?

“According to epidemiologists, it is now possible to know whether the current epidemic portend a wave of other, much more ambitious. But Beijing is silent” – written by Jean-Yves NAU, journalist and doctor of medicine, and Antoine Flo, Director of the Institute of global health at the medical faculty, University of Geneva, the publication Slate.fr.

“We should recognize that in China there is a slowdown in the spread of the virus, while in South Korea, Iran or Italy are developing a new epidemic foci”, – stated in the article.

“Should we interpret the change in Chinese epidemiological curves as the beginning of the next General reverse current? Or Vice versa, should be afraid of the second wave, even worse than the previous? Is observed from December wave is only a harbinger of the main wave, as observed in the tsunami? There may soon be an answer to such important questions,” the authors of the article.

“Officially today in mainland China was just over 80 thousand confirmed cases of infection Covid-19. The country has 1.4 billion inhabitants. The first indicators of flare calculated using the mathematical models allowed to predict that from 50% to 60% of the population will eventually be infected with the novel coronavirus ( … ), ” reads the article.

“By the way, why 50% or 60% instead of 100%? Simply because once infected, people remain immune for at least several months, this is enough to block the emergence of new infections on the background of the epidemic regime. This is what experts call “population immunity.” If there were a vaccine it would produce immunity to the same type”, – experts explain.

“Let’s take as an example became infamous cruise liner Diamond Princess. The observed incidence remained at around 20% (705 people infected with the coronavirus from 4061 passengers and crew members). So let’s leave the theoretical hypotheses about 50% -60% and we postulate that here we were in the low range. Meanwhile, 20% of China’s population is 280 million people!” – scientists argue.

“We also learned that on Board the Diamond Princess for almost half of cases (322 of 705) proceeded completely asymptomatic. In China during the epidemic in January and February 2020, many of these asymptomatic infections might have gone undetected and will not be registered by the surveillance system. Perhaps, but really we know nothing about it,” noted NAU and Flo.

“A serious question, because if we assume that in two months there were 80 thousand, 160 thousand and 800 thousand cases of infection, we are still very far from incidence of experimentally observed aboard the Diamond Princess, if to extrapolate them to China, then presumably will be infected 280 million Chinese people, not even mentioning the predictions given much more catastrophic mathematical models,” write the experts.

“If we face today, the phenomenon of the “mother wave”, to use the terminology of experts in tsunami to denote the waves-a precursor? Any approaching big wave?” – thinking of the authors.

“For the exact answer to this important question is the scientific method, proposed in studies of seroprevalence. The question here is simply about how to test the blood serum sample of people, which is more representative of the Chinese population, that is located in the epicenter of the epidemic in Wuhan, a city which has experienced the most intensive viral activity,” say the experts.

“Analyzing the samples taken from 1,000 people today, we could with high precision to provide an estimate of the rate of infection with SARS-CoV-2. Assuming that the sample is representative enough for the population of Wuhan, we could say, what happened to the incidence – indicators are much lower than from 1% to 5%, or 10%, 20% or more” – explain the authors of the publication.

“For our part, we have conducted several studies of seroprevalence in an emergency situation related to the crisis in health care, in particular, on the example of an epidemic caused by Chikungunya virus, transportable mosquitoes that occurred in 2006 in reunion and in Mayotte. This was the first study that we are qualified as “cursory and not very strict”(eng. “quick and dirty”), but it brought us results which can be very useful,” write the NAU and Flo.

“We got this result thanks to a study conducted using blood samples from a Bank of samples which were systematically taken from all pregnant women (and stored for other reasons, in particular, to check the absence of risk of toxoplasmosis during pregnancy),” – said in the article.

“We should recognize that pregnant women are not representative of the General population, nor do we necessarily recommend you to do the same in China”, – the scientists.

“But the fact remains – most recently, in September 2006, we were able to conduct a very strict examination, following all generally accepted professional standards, and get exactly the same results: the incidence of 40%, whereas the mathematical model predicted 75%”, – stated in the article.

“There is also another population group for which the stored frozen blood samples and which can be quickly available-that blood donors”, – experts say.

“Chinese blood banks may, upon request, to provide aliquote share a recent donor’s income for a “fugitive and not very rigorous” studies of seroprevalence because blood donors are not strictly representative of the population as a whole, but informative enough to directly or indirectly reduce the number of unknowns facing all of the medical and political figures of the planet in the fight against the epidemic Covid-19″, – it is recommended by scientists.

“In all of our interests to know the answer to these questions and, therefore, to conduct these types of studies as soon as possible, which is what we suggested in the journal the Lancet. Why, then, who recommended it with such caution? Why the Chinese government did not? And if it were, why the results are not yet published?” – thinking of the authors.

“To better guide public policy, such “fugitive and not very rigorous” studies must be carried out wherever will rage epidemic,” declares Jean-Yves NAU and Antoine Flo.

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