- The study — published in the Lancet medical journal Monday — reviewed more than 3.4 million people who were inoculated with the Pfizer COVID-19 vaccine.
Overall, the vaccine was 90% effective in protecting hospitalization and death from COVID-19 up to six months after the second dose, per The Washington Post.
- However, the study found that prevention could wane over time, dropping from 88% to 47% in six months after the second dose in some cases.
- The researchers said this is “probably primarily due to waning immunity with time rather than the delta variant escaping vaccine protection.”
Per ABC News, the study is in line with previously published data from Israel and the U.S. Centers for Disease Control and Prevention, which reviewed vaccine effectiveness over time. However, this study is an indication of how well the delta variant impacts immunity.
- “The effectiveness of the vaccine against the delta and non-delta variants remained high during the study, suggesting that the vaccines worked well even when a variant was present,” Dr. Simone Wildes, an infectious disease specialist, told ABC News.
In late September, the Food and Drug Administration approved the Pfizer-BioNTech COVID-19 booster vaccine for emergency use, specifically for those who are 65 years old and older, and those who might have medical issues that put them at risk for severe COVID-19.
- “This pandemic is dynamic and evolving, with new data about vaccine safety and effectiveness becoming available every day. As we learn more about the safety and effectiveness of COVID-19 vaccines, including the use of a booster dose, we will continue to evaluate the rapidly changing science and keep the public informed,” Dr. Janet Woodcock, the acting FDA commissioner, said in a statement.