TAMPA, Fla. — One of the most-comprehensive pieces of research of COVID-19 vaccine performance in "real life" scenarios found the inoculations lose some of their protective power over time.
The eight-month-long study included about 800,000 veterans — roughly 500,000 of whom were vaccinated.
The findings were recently published in the journal Science. They reveal the effectiveness of the three vaccines cleared for current use in the United States could drop up to 85 percent over the course of six months.
Researchers say immune systems and defense levels can wane over time. And, the Delta variant might have played a role in declining efficacy.
The drop was especially noticeable with the single shot of the Johnson & Johnson vaccine, where effectiveness fell from 86 percent to a mere 13 percent.
Pfizer dropped from 87 percent to 45 percent, and Moderna dipped from 89 percent to 58 percent in half-a-year's time, the study found.
The New York Times published an interactive article Thursday, comparing other research that's been coming out. For instance, the newspaper said a study in England looked at vaccine effectiveness against the Delta variant, specifically. It determined the Pfizer shot drops from 90 to 70 percent effective against symptomatic infection after five months. The same research found Moderna protection declined, as well, although less significantly.
Health experts say that's not an indication that vaccines don't work. In fact, they often still prevent deaths and hospitalizations. The nation's top medical experts say vaccines remain a crucial tool in the fight against the virus.
Mask-wearing and hand-washing can help protect you, too. New treatments are emerging as doctors continue to study COVID-19. Monoclonal antibody treatments have been shown to ease symptoms – especially when taken within the first few days after diagnosis.
The state's latest available data for Oct. 29 showed nearly 65 percent of Floridians had gotten a COVID shot. And, that number is growing. As of Nov. 10, Google data showed nearly 70 percent of the state's population had gotten at least one dose with more than 60 percent being classified as fully-vaccinated.
Click here to learn more about vaccine effectiveness research, as obtained by the Centers for Disease Control and Prevention.
Editor's Note: A version of this article was first published by Jennifer Hoff of our Minneapolis sister-station KARE 11 News.
