Pfizer and Astra Zeneca vaccines’ effectiveness against the Delta variant of SARS-CoV-2

The Delta variant (Β.1.617.2) of the novel coranavirus SARS-CoV-2 has spread to the entire world becoming a new wager in teh battle against the pandemic. A clinical study was conducted to determine the immunity of the available Pfizer and Astra Zeneca vaccines to check their effectivenes against the variants Alpha and Delta. The doctors of the Therapeutical Clinic of Athens National and Kapodistrian University Theodora Psaltopoulou, Panos Malandrakis , Yiannis Danassis and the rector Thanos Dimopoulos summarised the data as they were published in the international magazine New England Journal of Medicine.

The effectivess after one dose was 30.7 against the Delta variant and 48.7 percent for the Alpha variant with similar results for both vaccines. However, after the second dose of the Pfizer vaccine thet effectiveness was 93.7 percent against the Alpha and 88 percent against the Delta variant. After two doses of the AstraZeneca vaccine the effectiveness was 74.5 for the Alpha variant and 67 percent against the Delta variant.

Ιn conclusion, said the professors, the vaccines’ effectiveness after two doses and the completion of the inoculation is high against the symptomatic disease COVID-19 even against the new, more contaminant Delta variant. They also underlined the need for the immediate completion of the vaccination of all the population, especially of the vulnerable groups as the Delta variant spreads and is expected to prevail in the next period.