What You Need to Know about the AstraZeneca COVID-19 Vaccine


Dr. Todd Ellerin

Todd Ellerin, MD, Director of Infectious Disease

To date, we have three COVID-19 vaccines approved for use here in the United States—the two-dose Pfizer and Moderna vaccines, and the single-dose Johnson & Johnson vaccine.

A fourth vaccine from AstraZeneca, also known as the “Oxford vaccine,” has been a workhorse for countries outside the United States, helping to vaccinate millions of people in more than 100 countries.

The AstraZeneca vaccine may soon be under consideration by the Food and Drug Administration (FDA) for use in America. But many Americans are now nervous about this potential vaccine, after reading headlines generated by some big missteps in the company’s rollout.

I believe the AstraZeneca vaccine has enormous potential. But the company needs prove they can stop being careless about communication, data integrity, and how they conducted their clinical trials.

There are some legitimate concerns, but it’s important to remember that none have been proven.

Let’s take a look at some of the issues.

Communication snafus

AstraZeneca’s public relations nightmare began in the U.S. when the independent Data and Safety Monitoring Board (DSMB) questioned the 79 percent efficacy rate against symptomatic COVID-19 (and 100 percent efficacy in preventing hospitalization) initially touted by a company press release, saying the data was not complete and therefore the may not be accurate.

The drug maker reviewed the data and later issued an amended press release, which stated efficacy against symptomatic COVID-19 is 76 percent—still extremely effective. The updated data also shows that the AstraZeneca vaccine is still 100 percent effective in preventing hospitalization.

Here’s the important thing to remember: The FDA does not approve or deny medications based on press releases. It will review all of the data in the clinical trials.

The Centers for Disease Control and Prevention (CDC) also has an advisory committee that will also review the data for the AstraZeneca clinical trials and issue a recommendation.

If a vaccine is authorized for use in the U.S., its clinical data has been carefully reviewed and evaluated to ensure the medication is safe and effective.

Reported blood clots

The risk of blood clots has also made headlines in conjunction with the AstraZeneca vaccine. When we look back at the clinical trials for this vaccine, there were 21,000 participants and zero reported cases of blood clots in those patients.

The exact number of blood clots isn’t known, but the CDC estimates as many as 900,000 cases per year in the United States. Right now, researchers are trying to determine if there are an excess number of blood clots in people who receive the AstraZeneca vaccine.

The European Medicines Agency recently reviewed cases of reported blood clots due to the AstraZeneca vaccine and says “the vaccine is not associated with an increase in the overall risk of blood clots and that the benefits of the vaccine in combating the still widespread threat of COVID-19 continue to outweigh the risk of side effects.” (Emphasis mine.)

Some countries have decided to put a pause on using the AstraZeneca vaccine in certain populations as research continues. This is a good thing—it allows us to get a better understanding of the risks associated with the vaccines and allows us to rebuild trust.

A note about trust in COVID-19 vaccines

For me, the most frustrating thing about these “unforced errors” by AstraZeneca is their contribution in the erosion of public trust in vaccines.

Healthcare professionals have worked diligently to build trust in the safety of the vaccine, and to address the concerns of people who are hesitant to take any of the COVID-19 vaccines. It’s vitally important that the public trusts the vaccine as we try to win the race against variants and pandemic fatigue.

I look forward to the day when we see more good headlines than bad about the AstraZeneca vaccine.

If the FDA and CDC do their thorough review of the data and say the AstraZeneca vaccine is safe, I would recommend it to patients here in the U.S. if and when it’s available to them.

The best COVID-19 vaccine is the one that is available to you.

Learn more about COVID-19.