Data on Variants Supports Getting a COVID-19 Booster, Say MUSC Researchers

The pattern of the COVID-19 pandemic has been a series of waves: surges in COVID-19 cases and hospitalizations followed by declines. Spikes can be attributed to several factors, including human behavior, infection prevention policies, changes to the coronavirus itself, the effectiveness of vaccines over times, and “the number of people who are vulnerable because they have not developed some immunity, whether from natural infection or through vaccination,” according to a recent Johns Hopkins Medicine blog.

Health experts are warning of another wave as the omicron variant begins to spread and delta is still around. Michael Sweat, Ph.D., leader of the Medical University of South Carolina’s COVID-19 Epidemiology Intelligence Project, cautioned South Carolinians in an interview, “There’s a very, very strong probability a wave is starting.” Sweat leads a COVID-19 team that tracks four parts of the state where MUSC Health has hospitals. Cases increased 188% in one area in just one week.

Sweat attributes the increased number of cases to the delta variant as much as omicron. “There’s been a huge amount of concern in the press about omicron, but right now we’re facing a delta threat, and people have just largely given up on masking and distancing and other measures.” He added, “Pay attention to omicron, worry more about delta.”

A day after Sweat warned of a new wave, scientists at MUSC identified the first cases of the omicron variant in South Carolina. The findings were described in an article on the MUSC website. According to Julie Hirschhorn, Ph.D., director of the MUSC molecular pathology lab that discovered them, three cases were identified: “Two out of the three were fully vaccinated, but not boosted. And one had only one dose of the vaccine.”

Questions about transmissibility and severity of illness due to the omicron variant are still being studied. An analysis from South Africa found that the omicron variant was 2 ½ times more transmissible than the delta variant, Sweat said. Omicron’s measure of transmissibility is “something similar to measles, which is one of the most contagious things out there,” Sweat explained. Hirschhorn also pointed out how quickly the number of cases attributed to the omicron variant seem to be increasing. “The U.K. seems to be doubling cases about every day,” she said. “So it does seem to be more transmissible than delta.”

Hirschhorn added, “There’s not a whole lot of evidence about severity of disease yet, because we’re just starting to see the hospitalizations. … The hospitalizations in the U.K. also appear to, in early terms, suggest that it’s maybe more mild disease.”

But less severe disease, if that’s true, doesn’t suggest there’s no danger. “That’s great [if omicron is a more mild disease], except that if you have COVID circulating in large quantities, then you always have the ability for more mutations to happen. And so I think it’s pretty critical that people try and protect themselves in any way they can.”

That means getting vaccinated and getting a booster shot. “All three of our omicron cases were in people at least six months out from their last shot,” Hirschhorn noted. “The data supports that if you’re six months out, you should probably get boosted.”

The MUSC website features regular updates on the COVID-19 pandemic and vaccination, and MUSC Health highlights "Vaccine Fast Facts."