AstraZeneca's two-dose vaccine nearly 80-percent effective in U.S. trials

MADISON, Wis. (CBS 58) - AstraZeneca revealed their vaccine is 79-percent effective in preventing COVID-19 and 100-percent effective in preventing severe disease and hospitalizations. This means the U.S. could see distribution of its fourth coronavirus vaccine as soon as next month, if approved. 

The AstraZeneca efficacy data was released amid Wisconsin’s expansion of vaccine eligibility to millions more in the state on Monday, March 22. Wisconsin doctors say having another vaccine could help in the race against variants.

“We need to stay ahead of these variants to give them less opportunity to infect people,” said Dr. William Hartman, the principal investigator for UW Health AstraZeneca clinical trial.

Dr. William Hartman says more than 32,000 people of varying ages and backgrounds took part in the study. Vaccine efficacy ended up being 80-percent for U.S. participants 65 and older.

“This is an age group that they weren’t able to establish efficacy in Europe with,” he says.

The U.S. study involved two doses, a month apart, but in the U.K. when they spaced doses three months apart, the vaccine performed better.

“They actually even see enhanced efficacy, and so that’s something that the U.S. FDA will have to take into consideration when they’re evaluating this particular vaccine for its Emergency Use Authorization,” Dr. Hartman adds.  

In Europe, the AstraZeneca vaccine was paused due to an investigation of a small cluster of blood clots, but Dr. Hartman says the blood clots may not be associated with the vaccine. The U.S. study proved the vaccine to be safe.

“We saw no evidence of these blood clots in this trial, it’s something that obviously that we will have to continue to monitor,” he says.

The AZ vaccine is an adenovirus vaccine, similar to Johnson & Johnson’s. It’s cheap to make and can be stored in the refrigerator.

“Which means that this could be a workhorse vaccine for the entire world,” adds Dr. Hartman.

Dr. Hartman says AstraZeneca plans to apply for their Emergency Use Authorization in the next week or so.

“It’ll probably be a couple of weeks before it’s actually authorized for use,” Dr. Hartman said.

“Now, with two million more people eligible, we’re back in the spot where we probably don’t have enough vaccine for the number of people that are looking for it,” said Dr. Pothof, chief quality officer at UW Health.

With millions more eligible for vaccines in Wisconsin, UW Health is hoping to ease the burden by offering self-scheduled appointments on their website, while a fourth vaccine is in the process of gaining emergency use.  

“Anyone can go and look to see if there’s an appointment,” adds Dr. Pothof. “If you’re not a UW Health patient it doesn’t mean we won’t vaccinate you. There’s a few more steps, but we can use this with anyone.”

They’re encouraging people to pursue a vaccine even if there’s not an immediate opening.

“Sooner or later someone is going to have a dose,” adds Dr. Pothof. “We do want to vaccinate you, it’s just ,you know, being persistent, but at the same time having patience as we try to get through this list of people.”

Dr. Hartman says side effects of the AstraZeneca vaccine included sore arm, fever, chills and insomnia. If the vaccine gains Emergency Use Authorization in April, the company says they would be ready to distribute 30 million doses to the U.S. immediately.