As more COVID-19 vaccines near approval, Louisville epidemiologist examines differences

LOUISVILLE, Ky. (WDRB) -- A new vaccine from Johnson & Johnson would mean people could receive one of three different types of vaccines for COVID-19, and it would allow for less time spent waiting in line to be vaccinated.

The vaccine only requires one dose for full immunity to the virus. Currently, the Pfizer and Moderna vaccines require two doses, several weeks apart.

"The initial iteration may be a one-dose, but maybe later on, we'll figure out it's best to give two doses, or maybe some people should get two doses and some people only need one doses," said Dr. Paul Shulz with Norton Healthcare. "That could all happen or change later down the road as we get more information."

Shulz said some people have also voiced concern over the new vaccine's efficacy rates, but he said there's more to the numbers. Clinical trials show the Jansen vaccine from Johnson & Johnson is 72% effective, while the Moderna and Pfizer vaccines are both over 90% effective.

"In the Janssen trial, because of the timeline and the locations, they know there were some of these variants included in the data," Shulz said.

To build immunity to COVID-19, the Pfizer and Moderna vaccines use mRNA, genetic material that contains instructions for making proteins found on COVID-19.

"It's like putting a USB in a computer, and the computer sees there's a program there, and it runs it," Shulz said.

The one-dose Johnson & Johnson vaccine also targets the proteins found on COVID-19, but instead, it uses double-stranded DNA. The vaccine is referred to as an adenovirus-based vaccine. Adenovirus-based vaccines have been researched and used for decades to make vaccines for other illnesses like HIV, Ebola and the common flu.

Shulz said for now, patients likely won't be able to pick which vaccine they get.

"The best vaccine is the one you can get," he said. "During a pandemic, you don't want to be too choosy about what vaccine you get to the point you end up delaying immunization in a significant amount of people."

BROADBENT ARENA VACCINATION SITE — The COVID-19 vaccination facility inside Broadbent Arena in Louisville, Ky.

So far, Shulz says research shows those who have gotten the one-dose Johnson & Johnson vaccine reported having less severe side effects, such as flu-like symptoms, compared to those who received two doses of the Pfizer and Moderna vaccines.

Johnson & Johnson said it is ready to ship doses as soon as the vaccine is approved, but Shulz said it could take several weeks until they are available in the Louisville area.

Shulz, an infectious disease specialist and chief epidemiologist at Norton Healthcare, was also a sub-investigator in a Phase 3 clinical trial for the Johnson & Johnson COVID-19 vaccine. The trial was a partnership with the University of Kentucky and Baptist Health Lexington.