translated from Spanish: Study noted that pfizer vaccine effectiveness declines faster than AstraZeneca’s

The full schedule of the Pfizer/BioNTech vaccine is initially more effective against covid caused by the delta variant than that of the AstraZeneca/Oxford preparation, although the efficacy of the former declines more rapidly, according to a preliminary study published Thursday. The research, led by experts from the University of Oxford, found that, in infections with a high viral load, pfizer’s vaccine protection one month after the second puncture is 90% higher than that present in unc vaccinated individuals, but drops to 85% and 78% after two and three months, respectively. In the case of AstraZeneca, the equivalent protection offered by this preparation was 67 %, 65 % and 61 % respectively. The study, which has not yet been reviewed by the scientific community, analysed data from britain’s national health service (NHS) collected between December 2020 and August 2021.The experts also examined the tests of 700,000 patients taken before and after May 17, when the delta variant became dominant in the UK.Their results, the authors explain in a statement, suggest that those who contract covid-19 from the delta variant after the second puncture have maximum levels of virus similar to those of un vaccinated people. They also stress that although preparations do not eliminate the possibility of contracting the disease, they do reduce the risk of infection and remain the most effective way to ensure protection against the delta variant.” We still don’t know how much transmission can be caused by people who contract COVID-19 after being vaccinated. They may have, for example, high levels of the virus for shorter periods of time,” explains Sarah Walker, an expert in medical statistics and epidemiology at the University of Oxford.No however, she points out, the fact that these patients may have high levels suggests that “people who are not vaccinated may not be as protected from the delta as we expected.” This means it is essential that as many people as possible are vaccinated, both here in the UK and around the world,” adds Walker.Su colleague Koen Pouwels notes that, although Pfizer and AstraZeneca have “slight decreases in protection” against “all infections” and “infections with high viral load”, the overall efficacy of vaccines is “still very high”. In parallel, the experts also found that a dose of moderna’s preparation (developed in the United States) has an efficacy against the delta variant “equal to or greater” than the other two vaccines, but they do not yet have data to evaluate its effectiveness after the complete regimen. Regarding the intervals between doses, the study found that this factor does not alter the effectiveness of vaccines to prevent new infections, while detecting that the youngest groups (18-34 years) have higher levels of protection than those of the elderly (35-64 years). The researchers said their findings could serve to advise the Joint Committee on Vaccination and Immunization (JCVI), which must decide whether to recommend a third booster dose for the fall.

Original source in Spanish