Clinical trials are the best way to prove the effectiveness of a vaccine. In a clinical trial, researchers have very specific criteria to select participants. However, inclusion and exclusion criteria means that trial participants often do not represent the general population in the real world. To make sure that vaccines are safe and effective for all, we need to have real-world evidence.

Proof that the Moderna vaccine is effective

Researchers from Southern California followed 352,878 adults who received both doses of the Moderna vaccine. They compared this vaccinated group with the same number of unvaccinated people over the next 3 to 6 months. Then researchers compared rates of COVID-19 infection, including severe disease that resulted in hospital admission or death. The results showed that in a diverse, real-world population, compared to unvaccinated individuals, the Moderna vaccine reduced rates of COVID-19 infection by 87%. Also, the Moderna vaccine reduced hospital admission by 96% and death from COVID-19 by 97.9%. The vaccine effectiveness was similar in different age, sex, and racial/ethnic groups.

The study included health care workers, long-term care residents; older people (65 years or older); workers in education, child care, emergency services, food and agriculture; and people aged 18-64 with underlying conditions. Researchers monitored participants until June 2021. This time period overlapped with the emergence of the Delta variant in the U.S.

Real-world evidence of benefits from the Moderna vaccine

These results show the effectiveness of two doses of the Moderna vaccine across age, sex, and racial/ethnic groups. Further, the Moderna vaccine is proven to be effective against COVID-19 (with and without symptoms) and severe COVID-19 outcomes.


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