As booster shots roll out nationwide, scientists stress original vaccines are still working

Amid a nationwide campaign to promote COVID-19 booster shots, scientists say the original vaccines are still holding up remarkably well for most people.

Amid a nationwide campaign to promote COVID-19 booster shots, vaccine scientists and public health experts say vaccines are still holding up remarkably well for most people -- depending on how effectiveness is measured.

In fact, many scientists now worry that the recent booster shot authorization could give the false impression that existing vaccines are no longer offering protection.

"They all work well," said Dr. Paul Goepfert, an infectious disease physician and director of the Alabama Vaccine Research Clinic. "They aren't perfect by any means. But if your bar is prevention of hospitalizations in the United States, they still work incredibly well."

A vaccine's effectiveness can be measured in several different ways. One is their ability to protect people from mild infections. When first authorized, Pfizer and Moderna's vaccines proved 95% and 94% effective using this threshold, and Johnson & Johnson's single-shot vaccine proved 75% effective.