Doctors explain Johnson & Johnson vaccine's lower efficacy rate

Posted at 7:34 AM, Mar 18, 2021
and last updated 2021-03-18 07:55:32-04

TAMPA, Fla. — Experts say it’s difficult to compare the effectiveness of the COVID-19 vaccines because the clinical trials are all set up in different ways.

“So what they’re looking at in terms of efficacy is an endpoint. All three of the vaccines that we do have out there right now have defined that endpoint in a little bit of a different way,” said Dr. Michael Teng, Associate Professor of Medicine at the University of South Florida.

According to the CDC, the single-shot Jonhson & Johnson vaccine was 66.3% effective in clinical trials at preventing COVID-19 in patients. The multi-dose Pfizer and Moderna vaccines have 95% and 94.1% efficacy rates, respectively.

Some people tell us they have concerns about getting the Johnson & Johnson vaccine because its effectiveness is less than its counterparts, but experts stress there were different elements in play during each clinical trial.

“The Johnson & Johnson vaccine was trialed later and it was also trialed in places like Latin America and South Africa where these variants of concern that we’ve been talking about came up. So that also affects the vaccine efficacy as well,” said Teng.

He says the way vaccine effectiveness works is by lowering your risk of getting symptomatic infections.

“What we do know though is that for all three of the vaccines, they’re very effective against severe COVID, at preventing hospitalizations and preventing deaths,” said Teng.

Experts are urging people to get vaccinated with any of these vaccines, as soon as they’re able to because the highly contagious UK strain is now the dominant variant in Florida.

“Instead of opting out of getting vaccinated, you should actually get vaccinated to protect yourself because this variant is here,” said Teng.