The investigation carried out by the National Institute of Health Doctor Ricardo Jorge (INSA) found that, in people between 65 and 79 years old, the effectiveness of the vaccine against inpatients was 94 percent, a percentage that drops to 82 percent in the elderly from 80 years. Regarding deaths associated with covid-19, researchers estimated an effectiveness of vaccines that use the messenger RNA platform of 96 percent for the age group 65 to 79 years and 81 percent for those over 80 years, said the INSA in a statement, which had the collaboration of the Shared Services of the Ministry of Health (SPMS) and the General Directorate of Health (DGS) in carrying out the study.

These data, according to the institute, reveal that “vaccines provide substantial protection against hospitalizations and deaths related to the SARS-CoV-2 virus after the complete vaccination schedule”. The study also made it possible to test the reduction in the effectiveness of the vaccine up to three months after taking the second dose in the group of people aged 80 years and over, and the results “did not show evidence of a reduction in the effectiveness of these vaccines against hospitalisations and deaths associated with covid. -19 during this period of time”, advanced the INSA.

Conducted between February and August, the study covered about 1.9 million people aged 65 and over, through the crossing and analysis of data recorded in eight information systems of the National Health Service. Of the four vaccines being administered in Portugal, Pfizer and Moderna, with two doses, use this new technology based on a molecule called messenger RNA.

Another INSA study, released 24 August suggested that these vaccines are less effective at preventing infection with the Delta variant of the SARS-CoV-2 coronavirus. This work concludes that there is "significantly higher probability of infection by the Delta variant in vaccinated persons", roughly "double the risk of infection by the Alpha variant".