URMC, RRH Test New COVID Vaccine Against South African Variant

May. 3, 2021

The University of Rochester Medical Center (URMC) and Rochester Regional Health (RRH) are at the forefront of COVID research again as they join national studies to test a vaccine for the new, more transmissible South African variant of the coronavirus. The new vaccine, produced by Pfizer and BioNTech, is a slight twist on the companies’ highly effective existing COVID vaccine. 

By some estimates, current vaccines have us on target to end the COVID pandemic in 2021. But mutations in the virus that evade those vaccines could stymie our ability to return to normalcy.  While current vaccines are based on the genetic blueprint of the coronavirus that first emerged in China, the strain of the virus that eventually went on to become dominant worldwide is actually a slightly different version of the original virus, which picked up mutations when it arrived in Europe.  Since then, other variants of the virus have emerged in the U.K., Brazil, and South Africa.

“Our current COVID vaccines are based on a virus that has been slowly mutating from the original Wuhan strain that circulated at the beginning of the pandemic,” said Edward Walsh, M.D., a professor of Infectious Diseases at URMC who is leading the new studies. “While those vaccines are still effective, we need to keep an eye on new variants of the virus and develop new vaccines to continue protection into the future.”

Mutations in the spike protein of three COVID variants
Two mutations in the spike protein make the South African COVID variant easier to spread. Here the spike protein of the South African variant is compared to the UK variant and the original virus first reported in Wuhan, China.

One of the variants that have scientists particularly concerned is the one that emerged in South Africa last December. The so-called South African variant carries two mutations in the spike protein that scientists speculate helps it evade existing vaccines and antibodies and makes it easier to spread.

Shortly after the South African variant was discovered, Pfizer and BioNTech started developing a new vaccine to protect against it. The new vaccine, called BNT162b2SA, is just like its original, currently-approved COVID vaccine except the genetic code for the spike protein it carries has been updated to mimic the South African variant.

“The hope is that this new vaccine will provide better protection than existing vaccines against not only the South African variant but all of the variants that are currently circulating,” said study co-lead Ann R. Falsey, M.D., professor of Infectious Diseases and co-director of the Vaccine Treatment and Evaluation Unit at URMC. “But we need to do studies to verify that hope.”

URMC and RRH have joined two phase 3 clinical trials to test the new vaccine as a booster and as a stand-alone vaccine.

In the booster trial, seven local people who received two doses of the original Pfizer/BioNTech COVID vaccine in a previous trial were given a booster dose of either the original vaccine or the new BNT162b2SA vaccine. Participants will be followed to see if one vaccine provides better or longer-lasting immunity than the other.

The other trial explores how well the new vaccine protects people who have not yet been vaccinated for COVID. It has enrolled 300 healthy, unvaccinated adults across the U.S. – including 45 from the Rochester area. Because effective alternative vaccines exist, none of the participants were given a placebo. All received two injections of the new vaccine three weeks apart.

Participants will report side effects following each shot as well as any COVID symptoms they experience over the subsequent 18 months. Blood samples will be collected at regular intervals to determine how strong and long-lasting participants’ immune responses are. Researchers will also test to see if the antibodies from study volunteers effectively neutralize other emerging variants of the virus.

The findings of these studies will be important in preventing future surges of COVID infections and helping put a definitive end to this pandemic.