4:13 PM, Feb 27, 2020


AstraZeneca vaccine is 79% effective against symptomatic Covid-19, company says

Posted at 6:17 PM, Mar 22, 2021
and last updated 2021-03-22 18:17:34-04

(WXYZ) — AstraZeneca has announced the results from its long-awaited US-based clinical trial, saying that its COVID-19 vaccine is safe and provides strong protection against symptomatic infection.

I love sharing good news, especially when it comes to vaccines that fight this nasty virus. And the good news today is that AstraZeneca’s vaccine was found to be 79% effective against symptomatic infection. And 100% effective against severe disease and hospitalization.

Now, for folks over 65, the efficacy rate was actually a tad higher…it was 80%. And why that’s important is because older folks had not been well-represented in earlier studies. And some countries where the vaccine is already approved were limiting it to citizens under the age of 65.

Because I get questions all day long from my patients, wanting to know if the vaccines are really safe. So let me first start with the number of participants.

AstraZeneca’s phase 3 trial had over 32,000 people from three countries - the United States, Chile, and Peru. Two-thirds of them got the vaccine, which is two shots in the arm, four weeks apart. The rest were given a placebo. Now 20% were 65 years or older. And roughly 60% of that age group had underlying health conditions like heart disease, diabetes, and severe obesity.

Now, the data showed that the vaccine was well-tolerated not just by older folks but for all groups. As for blood clots, specifically thrombosis - which is a blot clot that formed in a deep vein - or events characterized by thrombosis, the data did not show an increased risk for those. And there were no cases of cerebral venous sinus thrombosis - which is blood clots in the brain. Or any cases of serious neurological problems.

It’s been reported that the government has already pre-ordered 300 million doses. Do we need that many? Well, let’s look at the current projected timeline.

AstraZeneca says it plans to apply for emergency use authorization in the first half of April. So if the FDA does grant approval, that might not happen until May. And by then, we’re supposed to have enough vaccines from Pfizer, Moderna & Johnson & Johnson for every American adult.

Having said that, I think having a fourth strong and safe vaccine is a good thing. In the meantime, as more vaccine doses become available it’s important for Michiganders to continue to get vaccinated when they can. And as I’ve said before, the best vaccine is the one that's in your arm.