Richland, Lexington counties have high COVID transmission rates again. What’s it mean?

After weeks of negligible numbers of new COVID-19 cases in Richland and Lexington counties, both have seen a quick rise in new infections in just over a month.

Both counties are now considered to have “high” rates of COVID-19 transmission, which is defined by the Centers for Disease Control and Prevention as more than 100 cases per 100,000 people over the past seven days. As of Wednesday, Richland County easily topped that threshold: 153 cases per 100,000 people over seven days, according to CDC data. The rate is worse in Lexington County: 196 cases per 100,000 people over seven days.

A high rate of coronavirus transmission means people in both counties are now encouraged to wear face masks indoors in public settings — regardless of whether they are vaccinated — under new guidance from the CDC and the S.C. Department of Health and Environmental Control. Health officials at the state and federal levels say wearing face masks may help stem the spread of the highly contagious COVID-19 delta variant, which has led to nationwide increases in infections.

It’s been a quick reversal in COVID infection trends for Richland and Lexington counties.

The average number of new weekly cases of COVID-19 in Richland County had dropped as low as eight in mid-June, before steadily rising, according to CDC data. As of this past Sunday, July 25, the county reported about 70 new weekly cases — a nearly nine-fold increase in just over a month.

Likewise, Lexington County had dipped to one or no new weekly COVID cases in early June before rising to about 60 per week as of July 25, CDC data show.

The upward trend is happening across most of South Carolina, with 44 out of 46 counties now experiencing “substantial” or “high” levels of COVID transmission as of the CDC’s most recent reporting on Wednesday. Only Bamberg and Greenwood counties are considered to have “moderate” transmission levels.

COVID-19 infections have increased more than sixfold in South Carolina over the past month, soaring from 1,132 in the last week of June to 6,850 this past week, according to DHEC data.

As a result, the number of COVID-19 patients in South Carolina hospitals has quadrupled since July 2. Far more of those patients are in intensive care units or on ventilators than were earlier this month, but thus far coronavirus deaths in the state have not spiked, public health data shows.

Unvaccinated or partially vaccinated individuals account for the vast majority of new coronavirus cases, hospitalizations and deaths, according to a recent DHEC analysis.

Among those patients for whom vaccination status could be determined, 93% of cases, 86% of hospitalizations and 90% of deaths in June were among those considered not fully vaccinated, state health officials said.

DHEC officials attribute the recent surge in cases to the extremely infectious delta variant, which likely makes up more than half of all cases in South Carolina and can spread rapidly through unvaccinated or partially vaccinated populations.

As of Tuesday, only 44.3% of eligible South Carolina residents were fully vaccinated, one of the lowest rates in the country.