My Patients Ask — Does the Pfizer mRNA vaccines work as well in the real world as it did in clinical trials?

According to two Israeli studies, the resounding answer is yes!

The most recent study, published in the New England Journal of Medicine, found the efficacy of the Pfizer/BioNTech COVID-19 vaccine was 94%.

The study conducted in Israel involving nearly 600,000 pairs of matched vaccinated and unvaccinated people.

The vaccine prevented:

  • severe disease in 92% of people seven days after the second dose,
  • prevented symptomatic infection in 94%, and
  • prevented hospitalization in 87%.

Clinical trials of the vaccine reported its effectiveness at almost the exact same figures.

An earlier analysis of data from Israel among more than 1.7 million people who received both doses of the Pfizer vaccine gave slightly different results, but still overall excellent results.

This study estimated the Pfizer vaccine’s effectiveness in preventing severe disease to be in the range of 87% to 96%.

To prevent COVID-19 positive cases (that is, any level of disease), its effectiveness was in the range of 66% to 85%.

This means that some number of COVID infections can still occur, although very few will be severe.

Vaccine effectiveness was somewhat greater among those younger than 60 than among older people.

As soon as we get more data on Moderna, I’ll let you know.

This blog was accurate as of the day of posting. However, as the COVID-19 pandemic rapidly evolves and the scientific community’s understanding of the novel coronavirus and the COVID vaccine develops, the information above may have changed since it was last updated. While I aim to keep all of my blogs on COVID and the COVID vaccine up to date, please visit online resources provided by the CDC, WHO, and your local public health department to stay informed on the latest news.

© Copyright WLL, INC. 2021. This blog provides a wide variety of general health information only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment from your regular physician. If you are concerned about your health, take what you learn from this blog and meet with your personal doctor to discuss your concerns.


This entry was posted in General Health. Bookmark the permalink.