COVID-19 cases are spiking in several of the least vaccinated states in the country and the highly transmissible Delta coronavirus variant is likely to blame, according to health officials.
The Delta variant, first detected in the U.S. in March, has seeped into South Carolina but has yet to suffuse the state in the same way it has the Great Plains region, where states like Missouri have seen case rates more than double over the past three weeks.
That could change quickly, however, due to South Carolina’s low vaccination rate, state health officials warned Wednesday.
“Missouri has really become the hot spot for COVID-19 in America,” said Dr. Johnathan Knoche, a public health medical consultant for the state Department of Health and Environmental Control. “And its vaccination rates are very similar to ours here in South Carolina.”
As of Thursday, Missouri had fully vaccinated 39.1% of eligible residents. South Carolina has inoculated 42.6%, according to DHEC.
Unless the state can start getting shots into more people’s arms, a surge in cases could be on the horizon, Knoche said.
“With the Fourth of July holiday just around the corner, we may see an increase in cases, including in cases of the Delta variant,” he said. “Unvaccinated people or those who choose not to follow disease control and prevention measures to protect against COVID infection put us all at risk.”
DHEC officials had identified only 10 Delta variant cases statewide, as of Monday, but the true number of Delta cases in South Carolina is likely far greater.
That’s because the state sequences only a tiny fraction of COVID-19 cases — less than 1% cumulatively since the beginning of the pandemic, according to the U.S. Centers for Disease Control and Prevention — meaning that most Delta variant cases likely go undetected.
Of the 195 samples sequenced at DHEC’s public health laboratory over the past four weeks, 78% were identified as variants of concern, a designation the CDC uses to describe strains that show evidence of increased transmissibility, more severe disease or resistance to vaccines or medical treatments.
Just over 5% of the variants of concern DHEC identified were of the Delta variety, also known as B.1.617.2, Knoche said.
While still a small proportion of total cases in South Carolina, Delta’s transmissibility makes it capable of expanding in scale rapidly.
The proportion of Delta cases in the Southeast (11.6%) and nationwide (26.1%) has more than doubled in the past two weeks, according to CDC estimates. Public health experts believe that Delta will soon become the dominant strain in the U.S., as it has in countries like Britain, where it accounts for more than 95% of new cases.
Delta has gained traction so quickly because it’s more transmissible than other variants of concern, including Alpha, which has long been the dominant strain in the U.S.
Researchers estimate the Delta variant is between 40% and 60% more transmissible than Alpha, which itself is 50% more transmissible than the original strain identified in Wuhan, China.
There’s not enough research yet to definitively say whether Delta also produces more severe illness in the people it infects, but some early data suggests it might lead to more hospitalizations than Alpha.
Research shows it’s also slightly better than Alpha at eluding antibodies the body makes after a COVID-19 vaccination, although all three brands of shots available in the U.S. are still highly effective against the Delta variant.
“Fully vaccinated individuals in South Carolina are about 88% protected from symptomatic disease and about 94% protected from being hospitalized due to the Delta variant,” said Knoche, adding that people who get just a single shot of the Pfizer of Moderna vaccine are only about 33% protected.
For that reason, he said, it’s crucial more people roll up their sleeves and get vaccinated.
“With the Delta variant contributing to more and more cases worldwide, we need to be encouraging all of our unvaccinated friends and families to get their shots now,” Knoche said.
If vaccination rates don’t increase in under-vaccinated areas soon, South Carolina is likely to see COVID-19 case rates jump in those areas, even if they remain flat in places where more people are inoculated.
“We don’t want to encourage having a gap widen between those who are vaccinated and more protected and those who are not vaccinated and are less protected,” Knoche said. “When you have these areas with low vaccination levels and a variant that has high transmission, those are the areas where cases, clusters and outbreaks are more likely to occur.”