According to a study of the working group on the effectiveness of vaccination against COVID-19, made up of the General Directorate of Public Health, the Carlos III Health Institute and the Spanish Medicines Agency, approved coronavirus vaccines lose effectiveness over time.
That is, the Pfizer / BioNTech, Moderna, Janssen and AstraZeneca vaccines lose their effectiveness when months have passed since its administration. The study, to which you have had access The Spanish, has shown that the effectiveness of vaccines it decreases over time in residents of senior centers.
The study indicates that people vaccinated from May presented 96% effectiveness, while the efficacy of the doses in those who were immunized in March was reduced up to 58% with or without symptoms, and until 64% if the infection was symptomatic.
“The results show that there has been a significant decrease in the effectiveness of vaccination, both against infection and against more serious episodes such as hospitalization or death, in people residing in centers for the elderly, which could be due to a loss of immunity of people vaccinated in February and March, moment in which it was vaccinated mainly in residences, since the protection in people vaccinated between April and May has remained at high levels “, indicates the study.
Efficacy by age, by vaccine and by gender
The study has also shown that the effectiveness of vaccines is four points higher in men than in women (80% in men, 76% in women). On the other hand, the vaccine that has presented the most efficacy during the development of the study was that of Modern: Janssen protection in symptomatic infections was 56%, AstraZeneca 68%, Pfizer 78% and in Modern 89%.
Finally, the analysis indicates that efficacy in people under 50 years of age is lower. The authors consider the possibility that young people have had a higher level of exposure to the virus as a reason for the low effectiveness.
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