New real-world protection data show that the effectiveness of Pfizer and AstraZeneca vaccines in preventing the symptomatic form of Covid-19 caused by mutant variants of the coronavirus is partially reduced-87.9% and 59.8% after two doses, respectively. The difference after the first dose was more significant, with a decrease of about 17% compared to the Alpha variant.
“Moderate” differences, especially after two doses: these are the differences found in the effectiveness of the UK anti-Covid vaccine, where Delta variant (B.1.617.2) Coronavirus SARS-Cov-2, also known as the Indian Coronavirus, has now become the dominant one, representing 96% of Covid-19 cases Sequencing on June 7.In Italy, according to the latest surveillance by the Higher Institute of Health dating back to May 18, we are talking about 1% prevalence And the recent outbreak Milan’s virgin gym, At least one case of Delta variant was found in a health care worker who had received two doses of the vaccine.
A rare but not accidental case, as the data on real-world protection in the UK shows, the data is represented in digital form for the first time Effectiveness of the two main vaccines (from Pfizer-BioNTech and Astrazenca) Prevent the symptom form of Covid-19 caused by the Delta variant.
Effectiveness of Covid vaccine against Delta variants
These data are reported by researchers from the Department of Public Health (PHE) and are currently studying the preprint MedRxiv (“Effectiveness of COVID-19 vaccine against B.1.617.2”) showed that the efficacy of the two doses of Pfizer-BioNtech and AstraZeneca vaccines against Delta variants was partially reduced, although the overall protection was still sufficient.
In detail, the data shows that the two doses Pfizer-BioNTech Have The average effective rate is 87.9% (78.2% to 93.2%) In terms of preventing diseases caused by the Delta variant, the Alpha variant (English) calculated 93.4% (90.4% to 95.5%), so an average decrease of 5.5 percentage points.
Similarly, even two doses AstraZeneca Compared to the Alfa al variant, the effectiveness is reduced by 66.1% (from 54% to 75%) 59.8% (28.9% to 77.3%) Compared with the Delta variant, the average difference is 6.3 percentage points.
Later the difference became more obvious Single dose vaccine Equal to an average reduction of 17.6%, the data of the two serums are similar. In detail, compared with the variant cases in the UK, the estimated dose protection rate has exceeded 51.1% 33.5% Oppose the Indian variant.
“The absolute difference in the efficacy of the first dose supports the choice Maximize the administration of two doses In the most vulnerable part of the population ——The researcher concluded that——. After only two doses of vaccine were found Moderate difference in effectiveness For variant B.1.617.2“.