Quickest available COVID-19 jab more important than brand

Published on Thursday, April 1, 2021

By: Karen Bascom

With three approved COVID-19 vaccines available, you might be wondering “which one should I get?”

Stop wondering, because experts agree: Get the one you’re offered.

The U.S. Food and Drug Administration has issued emergency use authorizations for three immunizations produced by Pfizer-BioNtech, Moderna, and Johnson and Johnson, respectively.

Dr. Leandro Mena, professor and chair of population health science at the University of Mississippi Medical Center, said people should take whichever vaccine their vaccination site or health care provider has available.

“If you look at the reported data are similarly effective at preventing death and hospitalization associated with COVID-19,” said Mena, an infectious diseases physician who was the principal investigator for UMMC’s clinical trial site of the Johnson and Johnson vaccine.

He also said there is no evidence any of the COVID-19 vaccines are more or less suitable for people with certain health conditions than the others. We know this because of the “rigorous” clinical trial process, Mena said. Each vaccine went through preclinical, Phase 1, 2 and 3 trials that evaluated their safety and efficacy during several months.

“During the pandemic, there was an unprecedented effort to compress this clinical trial process that generally takes five, six, seven or eight years, yet not a single step was skipped,” Mena said.

The trials moved quickly in part because they occurred during the height of the COVID-19 pandemic. With hundreds of thousands of new confirmed cases each day, investigators could compare outcomes between vaccinated and unvaccinated people during the course of a few months and get a robust sample. That’s not feasible with rarer diseases, Mena said.

Another reason was people volunteered for the trials quickly and readily.

“These first two trials (Moderna and Pfizer) required 30,000 volunteers each and the investigators needed a few months to recruit them,” Mena said.

Similarly, the Johnson and Johnson trial needed only a relatively short enrollment period to enroll more than 40,000 volunteers. And because “most adverse events occur within two months of vaccination,” Mena said, the FDA used the available data to issue an EUA while it continues to monitor for long-term safety and efficacy.

“The EUA is used when the need is such that there is a critical demand for the drug,” Mena said. “It doesn’t mean that the testing wasn’t rigorous.”

The FDA has used EUAs for decades, including for treatments of another virus-associated disease, human immunodeficiency virus infection. Mena, who specializes in HIV/AIDS (acquired immune deficiency syndrome) treatment and research, said there are a couple of similarities between the two viruses.

“We have a situation where we have a disease that disproportionately affects particular groups of people, where it has a high risk for those groups and we have a treatment (for HIV) or vaccine (for COVID-19) that has been shown to be effective and can save lives,” he said.

The main difference between the vaccines is their design. The Johnson and Johnson is a one-dose vaccine, while the other two are administered in two doses. Pfizer and Moderna use messenger RNA, which includes a genetic code that teaches the body to make a spike protein found on the SARS-CoV-2 virus. The Johnson and Johnson vaccine uses a viral vector as a “taxi,” Mena said, to deliver a spike protein.

The end result is the same: The body learns how to mount an immune response to the SARS-CoV-2 virus without becoming infected by the virus.

On March 22, Mississippi announced that one million doses of vaccine had been administered. As of March 24, the Mississippi State Department of Health reported about 24 percent of Mississippians had received at least one dose, and 14 percent were fully vaccinated.

With three options, vaccination efforts should pick up needed steam and get Mississippians closer to the 70 percent immunization rate UMMC specialists say will provide effective herd immunity and get the state back to a “new normal.”

“People should get a vaccine as soon as it is available to them and get whichever one is available,” Dr. Bhagyashri Navalkele, medical director of infection prevention and control at UMMC, said in February. And with new coronavirus variants recently identified in Mississippi, public health officials have since strengthened their calls for all eligible people to register for a vaccine appointment.

“This just reinforces our messaging how important it is to get vaccinated and protected now,” said Dr. Thomas Dobbs, Mississippi state health officer, during a March 19 press conference. “Time is of the essence.”

"The best vaccine to take is the vaccine that you can get, the vaccine that's available at that time," Dr. Paul Byers, state epidemiologist, said at the same event. "I don't think we have enough information to begin a prioritization of vaccine types."

In clinical trials, the Pfizer and Moderna vaccines were each about 95 percent effective at preventing symptomatic COVID-19. The Johnson and Johnson vaccine used different outcomes to assess effectiveness and found it was about 85 percent effective at preventing severe COVID-19.

“There are no studies that do direct comparisons between these vaccines and you would need to design another trial in order to know if one is actually more effective,” Mena said.

Even if you wanted to choose your own vaccine, the UMMC/MSDH registration does not allow that option. And if you are 16 or 17 years old, your only vaccine option is Pfizer, while the Johnson and Johnson and the Moderna vaccines are approved for ages 18 and older.

However, Mena said the vaccines will be going through the same rigorous clinical trials process to learn if they are also effective in children.

For more information about COVID-19 vaccines, read this FAQ.

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