Public health strategies that rely on group immunity to combat the covid-19 pandemic are a “dangerous fallacy,” warns a group of 80 international scientists in an open letter published this Wednesday by The Lancet magazine.
Allow the virus to spread among population sectors with fewer risk factors, while protecting the most vulnerable people, it is a path that “is not supported by scientific evidence”, the researchers warn.
“The evidence is very clear: controlling community infections of covid-19 is the best way to protect our societies and economies, until vaccines arrive in the coming months …
“The evidence is very clear: controlling community infections of Covid-19 is the best way to protect our societies and economies, until effective vaccines and therapeutic methods arrive in the coming months,” consider the signatories of the text.
Among them are experts in public health, epidemiology, pediatrics, sociology and virology, among other disciplines.
In the text they emphasize that it is not yet clear how long immunity against coronavirus is maintained after having overcome the disease, and it is not completely understood who can suffer long-term sequelae. Betting on group immunity, they argue, can lead to a series of new waves of the pandemic over several years and place the vulnerable population in a situation of risk for an indefinite time.
Experience already gained during the first wave suggests that it is “Practically impossible and very unethical to isolate large sections of society”, say the researchers, who believe that uncontrolled transmission among young people increases the risk for the rest of the population.
The authors of the letter admit that the restrictions of recent months in many countries have caused a “demoralization and loss of confidence” among citizens, which has led some governments to evaluate the possibility of relaxing the measures during the second wave, but they emphasize that it is essential to control the infections “urgently”.
The letter in “The Lancet” also warns that Lack of contagion containment measures can jeopardize the capacity of health systems.
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This strategy also implies “an unacceptable burden for health workers, many of whom have died from COVID-19 or have suffered trauma as a result of having been forced to practice disaster medicine.”
“It is necessary to implement effective measures to suppress and control the transmission (of the virus), and must be accompanied by financial and social programs “ that cushion the negative consequences of these restrictions, particularly for the most vulnerable sections of the population.
This week, the World Health Organization (WHO) itself warned that “It is not an option” to let the new coronavirus circulate freely for the population to acquire herd immunity, as some have suggested. “Never in the history of public health has herd immunity been used as a strategy to respond to an epidemic, much less a pandemic. It is scientifically and ethically problematic ”, declared the head of the WHO, Tedros Adhanom Ghebreyesus, in a press conference.
“Letting go of a dangerous virus, about which we do not understand everything, is simply unethical. It is not an option, ”he insisted.
He also explained that the world does not know much about the immunity enjoyed by people who contracted the virus, and stressed that some were infected again. “Most people infected with the virus develop an immune response in the first weeks, but we do not know if this response is strong or long-lasting, or if it differs from person to person,” he explained.
He stressed that the concept of herd immunity is used in vaccination campaigns and recalled that for smallpox it is required that 95% of the population be vaccinated so that the remaining 5% is protected. For polio the rate is 80%.