After two years of a pandemic that saw nearly 500 million people become infected and billions vaccinated, studies have highlighted the importance of piercing for those who have natural immunity after recovering from the disease. One of two studies published in the medical journal The Lancet Infectious Diseases analyzed the health data of more than 200,000 people in 2020 and 2021 in severely affected Brazil, which has the second highest number of COVID deaths in the world. For people who had already had COVID, the Pfizer and AstraZeneca vaccines found 90 percent efficacy against morbidity and death, China’s CoronaVac had 81 percent, and the Johnson & Johnson vaccine had 58 percent. a hundred. “All four of these vaccines have been shown to provide significant additional protection to those with a previous COVID-19 infection,” said study author Julio Croda of the Mato Grosso do Sul Federal University. “Hybrid immunity due to exposure to natural infection and vaccination is likely to be the norm worldwide and can provide long-term protection even against emerging variants,” said Pramod Kumar Garg of the Institute of Translational Health Science and Technology in India. associated with the study. A study using the Swedish National Register until October 2021, meanwhile, found that people who recovered from COVID maintained a high level of protection against re-infection for up to 20 months. And people with hybrid immunity to two-dose vaccines had an additional 66 percent lower risk of re-infection than those with just natural immunity. Paul Hunter, a professor of medicine at the University of East Anglia who did not participate in the study, told AFP that 20 months of “very good protection” from natural immunity was “much better than we would expect for the initial two doses.” vaccine program “. However, he warned that both studies were completed before the Omicron variant became dominant worldwide and that it had “significantly diminished the protective value of a previous infection”. A study in Qatar published on the pre-publication website medRxiv last week provided an insight into the protection that hybrid immunity offers against Omicron. Immunity pic.twitter.com/o2V2QTz3Op – Randall Munroe (@xkcd) December 20, 2021 Three doses of the vaccine were found to be 52 percent more effective against symptomatic infection with the BA.2 Omicron subtype – but that number rose to 77 percent when the patient was previously infected. The study, which has not been peer-reviewed, found that “hybrid immunity resulting from previous infection and recent booster vaccine provides the strongest protection” against subtypes BA.1 and BA.2. © Agence France-Presse
