Collective immunity to Covid-19 could prove “unattainable,” according to a new large-scale Spanish study. In fact, antibodies to the virus may disappear after only a few weeks in some patients. The Spanish government has teamed up with some of the country’s top epidemiologists to find out what percentage of the population has developed antibodies that can confer immunity to the coronavirus. The study found that only 5% of people tested in the country retained antibodies to the virus, according to findings published in the medical journal The Lancet. In addition, “immunity may be incomplete, it may be transient, it may only last a short time and then disappear,” according to Raquel Yotti, director of the Spanish Institute of Health Carlos III, who helped carrying out the study. In fact, the study also revealed that 14% of people who tested positive for antibodies to the coronavirus during the first series of tests were no longer positive during subsequent checks carried out weeks later.
Other researchers said the study corroborated other conclusions that immunity to the virus may not last long in people who develop only mild symptoms, or even those who do not develop any symptoms. “The absence of symptoms suggests a mild infection, which never really allows the immune system to function well enough to generate ‘immunological memory’,” said Ian Jones, professor of virology at the University of Reading, England. He adds that “anyone who tests positive for antibodies should not assume that they are protected. They may be, but it’s not clear. ” The study’s lead author, Marina Pollán, told CNN: “Some experts have calculated that around 60% of infected people could mean collective immunity. But we are very far from reaching this figure. ”
The study found that, although Spain is one of the countries most affected by Covid-19, “estimates of the prevalence of antibodies remain low and are clearly insufficient to ensure collective immunity”. In Spain, more than 28,000 people died after catching the coronavirus.
Read also – Pregnant women may be more likely to suffer from serious coronavirus infections
As noted by CNN, The Lancet published comments from two other scientists, Isabella Eckerle and Benjamin Meyer, who said that the Spanish study, as well as similar studies in the United States and China, showed that l collective immunity could not be obtained. Isabella Eckerle heads the Geneva Center for Emerging Viral Diseases, while Benjamin Meyer is a virologist at the University of Geneva. The “main conclusion” of this study is that “most of the population appears to have remained unexposed” to the coronavirus, “even in areas where the virus is widely circulated,” said the scientists. They added: “In light of these results, any approach proposed to obtain collective immunity through natural infection is not only highly unethical, but also unworkable.”
As studies on antibodies elsewhere in the world show, the most densely populated areas of Spain – the cities of Madrid and Barcelona – have the highest levels of antibody prevalence. This level was above 10% in Madrid and 7% in Barcelona. The Spanish study, which tested more than 61,000 people, is the latest to distance itself from the idea of collective immunity.
Last May, a study suggested that only 7.3% of the inhabitants of Stockholm, the Swedish capital, had developed antibodies against coronaviruses, despite the adoption by the Swedish government of a new and controversial strategy of not imposing strict containment. Swedish Prime Minister Stefan Lofven last week ordered an investigation into the country’s handling of the virus, telling reporters that “we have had thousands of deaths”, and adding that “the question now is how Sweden should change, not if it has to. ”
Unlike most European countries, Sweden has not implemented strict and comprehensive containment measures in response to the pandemic. Instead, it has largely allowed businesses and hotels to stay open and students to attend schools. In May, Swedish epidemiologist Anders Tegnell justified this response to the health crisis by saying that countries which have imposed strict containment measures are likely to suffer a second major wave later in the year, while that of Sweden would smaller.
New Spanish study, however, casts doubt that Sweden, which has reported nearly 5,500 deaths from coronavirus and has one of the highest deaths per capita in the world, may be better prepared to avoid a second wave.
Also read – 239 scientists say coronavirus could be transmitted through the air in an open letter to WHO