The results, not yet reviewed by independent scientists, add to recent data that concluded that the vaccine, administered in two doses and that several countries, including Portugal, do not recommend it to people over 65, due to lack of proven efficacy in clinical trials, it is effective in the elderly.
Researchers at the University of Bristol, UK, studied a group of patients over 80 years hospitalized in England with respiratory disease (with or without covid-19).
The group was separated into two subgroups: One with patients diagnosed with covid-19 and the other with patients who tested negative for covid-19.
The team of researchers also noted how many patients had taken the first dose of the Pfizer / BioNTech vaccine (which is also a double dose) and how many received the first dose of AstraZeneca / Oxford.
Among the 36 patients diagnosed with covid-19, nine (25%) received an injection of the AstraZeneca / Oxford vaccine at least two weeks before their hospitalization.
In contrast, among the 90 patients who tested negative for covid-19, 53 (58.9%) took a dose of the same vaccine in identical circumstances.
The difference found leads the authors of the analysis to point out an 80.4% efficacy of the AstraZeneca / Oxford vaccine in reducing severe forms of covid-19.
For the Pfizer / BioNTech vaccine, the calculated efficacy is lower, in the order of 71.4%, taking into account that 18 of the 245 patients diagnosed with covid-19 received an injection, against 90 of the 269 patients who tested negative for the new coronavirus .
The study authors note that the number of patients studied with the Pfizer / BioNTech vaccine is higher, because it started to be administered earlier in the UK than the AstraZeneca / Oxford vaccine.
The latter vaccine, which the United Kingdom has given to adults, including elderly people of different ages, continues to be recommended by the World Health Organization for people over 65.
The covid-19 pandemic has already claimed at least 2,549,910 deaths worldwide, resulting from more than 114.7 million cases of infection, according to a report made by the French news agency AFP.
In Portugal, 16,430 people died of the 806,626 confirmed cases of infection, according to the most recent bulletin from the Directorate-General for Health.
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