Both are vaccines and use the messenger RNA technique, which is why they are comparable. And Harvard University studied its effectiveness through analysis of health records from the United States Department of Veterans Affairs, the largest health care system in this country.
In total, the Harvard researchers analyzed data from three million veterans, albeit with diverse cohorts that allowed them to conduct the study methodically:
Subjects were analyzed in pairs, with demographic, age, race, and gender similarities. The only difference between each member of the couple was the type of vaccine they were given: Pfizer or Moderna.
Which vaccine is better, Pfizer or Modern?
First round:
The initial phase of the Harvard study lasted 24 weeks and gave valid results until before the appearance of the Delta variant.
The victory in this first moment was for Moderna, since there were 4.52 positive cases of COVID-19 per 1,000 subjects in people who were vaccinated with this antigen.
In contrast, in the group who were vaccinated with Pfizer, it was found that there were 5.75 positive cases per 1,000 people.
This means that those protected with Pfizer were 27% more likely to contract a COVID-19 infection.