The out-of-control spread of the pandemic is facilitating the emergence of new variants of the coronavirus that partially escape human defenses. There are already five vaccines that seem to be less effective against the variant of the virus detected for the first time in South Africa and present in 40 countries , including Spain, where six cases have been certified . Last Wednesday, doctors from a French hospital reported the first confirmed case of serious reinfection by this variant. The more than 100 million people who have already overcome the covid and the more than 175 million who have already been vaccinated may not be fully protected against new versions of the coronavirus.
The French case is anecdotal at the moment, but disturbing. A 58-year-old man, asthmatic, suffered a mild covid in September, with a slight fever and difficulty breathing. In January, he had to be admitted and intubated for a serious reinfection with the South African variant, according to his doctors, at the Louis Mourier Hospital, in Colombes, very close to Paris. The doctors themselves emphasize that only three dozen reinfections have been confirmed in the world since the beginning of the pandemic, most of them milder than the first infection, although they warn that it is a "probably underestimated" figure.
French doctors have published the first confirmed case of severe reinfection with the variant detected in South Africa
"There is convincing evidence that having already passed an infection with the original virus does not protect against reinfection with the B.1.351 variant [the one detected in South Africa]," warns Dr. Shabir Madhi , from the University of the Witwatersrand, in Johannesburg. Madhi has led a trial of the vaccine by the American company Novavax that has obtained unexpected preliminary results. Half of the 4,400 participants received injections of saline water, for comparison. Some 700 had already overcome the covid months ago, before the new variant appeared in South Africa. The surprise has been that, in this unvaccinated control group, people who had never had covid and those who had had the disease were infected or reinfected at the same rate, touching 4% in both cases. "Previous infections did not protect against variant covid ," Novavax said on February 2. Madhi notes that only mild or moderate cases were observed. "They may be protected against the severe disease caused by the variant," he hypothesizes.
The Novavax vaccine is one of five that has shown evidence of being less effective against variant B.1.351. It was 89% effective in a UK trial, but just 60% in South Africa . The injection of the also American Johnson & Johnson reached an efficiency of 72% in the USA, but only 57% in South Africa . And the African country has directly suspended the administration of the Oxford and AstraZeneca vaccines after observing an efficacy of just 22% in a preliminary trial.
A small study with 20 people published last week in the journal Nature suggests that the vaccines of Pfizer and Moderna are also slightly less effective against viruses with the E484K mutation , such as the variant identified in South Africa and the one first detected in Brazil. "Mutations in the virus are reducing the ability of antibodies to neutralize it," warns Argentine biologist Rafael Casellas , co-author of the research.
"There is convincing evidence that having already passed an infection with the original virus does not protect against reinfection with the variant detected in South Africa," warns Dr. Shabir Madhi
The magnificent good news is that vaccines, although they do not prevent all infections, do have practically absolute efficacy in preventing the most serious cases of covid. “The prediction is that current vaccines will keep people out of the hospital, but at the same time the virus will have the ability to reproduce in those infected so that it continues to spread in society,” explains Casellas, head of a laboratory in the The US National Institutes of Health is of the opinion that covid vaccines will have to be periodically updated , as is done with flu vaccines .
Casellas believes that people who have already passed the covid and are reinfected with a new variant will have "few or perhaps no symptoms." The problem, he stresses, is that if the virus continues to be transmitted among those vaccinated, it will be impossible to achieve herd immunity. With other viruses, such as polio, it is necessary to vaccinate 80% of the population to achieve this collective immunity. The remaining 20% is also protected indirectly, because the virus stops circulating among the vaccinated, which act as a firewall for the unvaccinated. If the new variants of the coronavirus more easily infect already vaccinated individuals, even if it is asymptomatic, the people who have not been vaccinated will not be protected by the phenomenon of herd immunity. In addition to anti-vaccines, citizens who cannot be vaccinated because they are allergic to any component of the drug or for some other medical reason would lose out.
In Spain there is no re-infection with the new variants, according to sources from the Ministry of Health. The biologist Iñaki Comas , co-director of the Spanish consortium that monitors the genomes of the coronavirus, stresses that reinfections are difficult to demonstrate. Hardly any cases have been published in the world. The Oswaldo Cruz Foundation announced on January 18 the first confirmed reinfection with the variant detected in Brazil: a 29-year-old woman, resident in Manaus, was infected in March 2020 with the classic virus and in December with the new variant, in both cases with fever, cough and little else. Comas, from the Institute of Biomedicine of Valencia (CSIC), emphasizes that there are very few published cases. "We do not know what the reality is," he acknowledges.
Researchers at King's College London have calculated that the British variant does not cause more reinfections than the classic versions
The third worrying variant, in addition to those detected in South Africa and Brazil, is the one observed for the first time in the United Kingdom, presumably around 35% more contagious . A team of researchers from King's College London has calculated that the reinfection rate with this new variant barely reaches 0.7%, a figure similar to that estimated for the classic variants. The very preliminary results come from the analysis of data supplied by 37,000 users of a mobile phone application created to investigate the symptoms of covid.
A preliminary study with 20,000 health workers in the United Kingdom suggested in January that a Previous infection offers 83% protection against a new infection for at least five months. The Indian doctor Soumya Swaminathan, chief scientist of the World Health Organization, recalled this fact on Friday . The available scientific evidence indicates that both vaccines and previous infections generally protect against severe cases of covid, those that end in hospitalizations or deaths, Swaminathan added.
Virologist Theodora Hatziioannou , from Rockefeller University (USA) ), he acknowledges his uncertainty. “We don't know what levels of neutralizing antibodies [generated after a first infection] are needed to stop reinfection. Given that the rate of decline [of antibodies over time] is extremely variable from one recovered patient to another, I would assume that the risk of reinfection will also be variable, ”he argues. Hatziioannou, co-author of the study published in Nature , insists that it is necessary to control the transmission of the coronavirus, whether they are new variants or not, and that is achieved with the usual measures, such as masks and physical distance.
“Our experiments in the The laboratory cannot predict what will happen with respect to reinfections, ”admits immunologist Michel Nussenzweig , also from Rockefeller University. The researcher, however, sends a reassuring message: “Our forecast, based on the data, is that vaccines will also moderate the symptoms and severe cases of the disease produced by the variants, although this will have to be proven. And most importantly, vaccines can be quickly modified to optimally match the variants. " Some companies, such as Pfizer and Moderna, have already announced that they are working on improved vaccines against new versions of the coronavirus.
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