UAB experts warn Delta variant could become dominant strain in U.S. within weeks

Experts from the University of Alabama at Birmingham encourage everyone to get vaccinated to prevent the spread of the Delta variant, which is believed to be much more contagious and more harmful than original strains.

Midsection of female doctor with swab test sample during COVID-19 crisis. Female medical professional is holding test tube in hospital. She is wearing protective suit.Experts from the University of Alabama at Birmingham encourage everyone to get vaccinated to prevent the spread of the Delta variant, which is believed to be much more contagious and more harmful than original strains. The Delta variant — the latest strain of the SARS-CoV-2 virus that causes COVID-19 — is spreading rapidly throughout the world. It is expected to become the dominant strain in the United States within the next few weeks. With almost two-thirds of Alabamians unvaccinated, some health care providers are concerned there will be a resurgence of COVID-19 in the fall. 

The number of Delta variant cases nationwide has doubled over the last few weeks and now accounts for nearly 20 percent of cases in the United States. According to Jeanne Marrazzo, M.D., professor of medicine and director of the University of Alabama at Birmingham’s Division of Infectious Diseases, this variant is between 50 and 90 percent more infectious than the other COVID-19 variants.  

“Delta is clearly escalating in the U.S. and will become the dominant variant in the next couple of weeks,” Marrazzo said. “We’re in an arms race against these evolving variants. We have a window of time when we can ramp up vaccinations in our vulnerable populations, including young people at this point, in order to stave off the chance that this variant is going to get a substantial foothold in our population.” 

For video clips from UAB experts discussing the Delta variant, click here.

The variant itself is believed to be more harmful than original strains. If an individual becomes infected with the Delta variant, evidence suggests that they are more likely to be hospitalized or severely ill. 

Paul Goepfert, M.D., a professor with the UAB Division of Infectious Diseases, says the leading hypothesis describing the Delta variant is that it has changed the composition of the virus’s spike protein to allow itself to enter a cell more efficiently. This mutation allows the spike protein to better attach to the cells that line the respiratory tract, including the throat, nasal passages and lungs.  

To put the transmissibility of the virus into perspective, Michael Saag, M.D., director of the UAB Center for AIDS Research and professor in the School of Medicine, explains how quickly one can become infected with the Delta variant.   

A female health care worker wearing a face mask is vaccinating a female student wearing a face mask against COVID-19 (Coronavirus Disease) by a health care worker at Bartow Arena, May 18, 2021.The best way to stop new variants is to get vaccinated.
(Photo by: Andrea Mabry)

“If you are in an enclosed space with somebody with the original strain, it may take eight to 10 minutes on average for you to pick up the infection,” Saag said. “With the Delta variant, you might be in the room for less than a minute, and you can become infected with the virus. That’s how infectious it is, and the people who are the most vulnerable are the unvaccinated.”

Goepfert emphasizes that current evidence suggests the mRNA vaccines are up to 90 percent effective against COVID-19 variants and reminds people that the other coronavirus strains developed when there was little to no vaccine around. 

“Thirty percent of Alabamians are fully vaccinated, but the rest are not,” Goepfert said. “So, we have a virus that sees an immune system that it wants to get around. If COVID has taught us anything, I suspect this virus is going to learn to mutate into a new variant to get around the vaccine-induced immune response. The best way to never see this new variant is to stop it from developing in the first place. The way to do that is by getting vaccinated.”

Saag says even children are at risk for experiencing severe illness and hospitalization with the new variant and encourages parents to get their eligible children vaccinated. He added that young people in particular are a reservoir for continuing the propagation of the virus and getting them vaccinated is an important step in mitigating the spread of the coronavirus.

“If you are in an enclosed space with somebody with the original strain, it may take eight to 10 minutes on average for you to pick up the infection,” Saag said. “With the Delta variant, you might be in the room for less than a minute, and you can become infected with the virus. That’s how infectious it is, and the people who are the most vulnerable are the unvaccinated.”

“Vaccination rates are relatively low for Alabama, and when — not if but when — Delta gets here in larger numbers, it’s like kindling wood for a wildfire,” Saag said. “Without the vaccine, it’s like playing Russian roulette with the virus.” 

Experts are expecting to see a doubling of the Delta variant in Alabama within the coming weeks and expect the variant to account for 40 to 50 percent of the cases by mid-July. Over the next few months, the UAB team will be watching hospitalization rates and gathering information on how children respond to the Delta variant, the degree of protection the vaccine provides and whether booster shots may be needed.  

For more information on how you can get vaccinated at UAB, click here.