COVID-19 Vaccine Effectiveness Estimated to Turn Negative Over Time in Children: Study

By Zachary Stieber September 14, 2022 Updated: September 14, 2022 The effectiveness of Pfizer’s COVID-19 vaccine against infection turned negative over time for children aged 5 to 11, according to a new study. Researchers found that for kids in the age group, the effectiveness peaked at 60 percent to 70 percent several weeks after the first dose. It … Read more

Moderna COVID-19 Vaccine Effectiveness Turns Negative Within Months: Study

A nurse administers a COVID-19 booster vaccination at a COVID-19 vaccination clinic in San Rafael, Calif., on April 6, 2022. (Justin Sullivan/Getty Images) By Zachary Stieber October 10, 2022 Updated: October 11, 2022 biggersmaller Print The effectiveness of Moderna’s COVID-19 vaccine against infection turns negative over time, according to a new study that was funded by the vaccine maker. The … Read more