NC’s COVID surge is steeper than it was months ago. Here’s why this wave is different.

North Carolina’s daily COVID-19 cases have been surging since early July, and the state reported 6,892 new cases on Sunday.

How does this current surge compare to the last spike following the holidays this past winter?

“What we’re seeing right now is an amplification in the spread of the increase in the number of [COVID-19] cases, and that’s worrisome to me,” said Dr. Pia MacDonald, an infectious disease epidemiologist at RTI International, a nonprofit research institute in Research Triangle Park.

Multiple experts agree that the speed of the increase in the number of cases per day is faster now than it was over the winter, and that’s due to the highly contagious delta variant.

From June to October of 2020, the number of daily new coronavirus cases reported were mostly in the 1,000s or 2,000s range, with several exceptions where the state only reported a few hundred new cases. On Nov. 11, the state reported over 3,000 new cases for the first time. On Nov. 19, there were over 4,000 new cases for the first time.

But the current surge in COVID-19 cases in North Carolina looks a little different. On June 30, 208 new cases of COVID-19 were reported in North Carolina. But it only took until Aug. 5 for the state to report over 4,000 new COVID-19 cases.

The number of new cases every day is “definitely increasing at a faster rate” than it did over the winter, said Dr. Susan Kansagra, acting senior deputy director for the Division of Public Health and section chief of the DPH chronic disease and injury section at the North Carolina Department of Health and Human Services.

Dr. Mandy Cohen, Secretary of the N.C. Department of Health and Human Services, spoke with a sense of urgency about the current wave of COVID-19 cases at a July 29 news conference.

“This rise in cases is faster than what we have seen with past increases,” Cohen said. “This is because the COVID-19 virus is now much, much more contagious than it was earlier.”

How quick are these numbers rising?

The amount of new cases each day has generally increased throughout July.

By July 8, North Carolina was regularly reporting over 500 new cases a day. By July 15, over 1,000 new cases were being reported most days. On July 28, 2,633 new cases were reported, and the state has reported over 2,000 new cases a day since then. The state reported 4,331 cases Aug. 5.

So far, the state has reported 13,759 total deaths due to COVID-19.

But North Carolina is projected to see a total of 16,758 COVID-19-related deaths by Dec. 1 if the delta variant of SARS-CoV-2, the virus that causes COVID-19, continues to spread and vaccine distribution is “scaled up over 90 days.” That’s according to the Institute for Health Metrics and Evaluation at the University of Washington.

If 95% of North Carolinians wear masks, the projection drops to about 14,982 people; if mobility moves towards pre-COVID-19 levels in the vaccinated population, the projection is that about 18,634 North Carolinians could die.

Why is this COVID-19 surge happening?

Kasangra, MacDonald and Cohen all point to one main cause of the steeper summer surge — the delta variant.

The delta variant is more transmissible than the ancestral strain of the virus.

“Public health experts were estimating that if somebody was infected with the previous strain, in the absence of any other type of interventions, they would infect an additional two to three people,” Kasangra explained. “With the delta variant, that estimate goes up to about six people, again in the absence of other interventions.”

Cohen said in a news conference that the delta variant is “by far the most dominant variant that we have seen thus far.”

Adds MacDonald, “What we’re seeing is that with the delta variant, one person gives it to more people than the ancestral variant, and that’s why we’re seeing the growth happening so fast.”

Is it different in unvaccinated versus vaccinated communities?

Kasangra said that there is a correlation between sharp COVID-19 case increases and the vaccination rate of a county or area. The News & Observer reported in July that vaccination rates in most of the Triangle were higher than the statewide average, and inversely, spread was lower in these counties.

However, MacDonald noted that with the delta variant, “we’re seeing vaccinated people can pretty efficiently move the virus from one person to another.” This is different than in earlier variants.

“If you have a bunch of people who are vaccinated, it’s going to move less effectively through that population in terms of people getting symptomatic from it,” MacDonald explained.

“But the problem with delta is that we’re seeing quite a few people who are vaccinated getting infected with the virus and passing it onto others,” MacDonald said. “So it’s not that transmission may be different among vaccinated versus unvaccinated people, but you’re going to find more symptomatic people in non-vaccinated groups.”

What causes surges and peaks?

MacDonald and Kasangra noted that the peak in the winter corresponded with the timing of the holidays and gatherings. Families came together to celebrate Thanksgiving and December holidays like Christmas and New Year’s Eve, which could promote transmission.

“If we think about communicable disease, especially things that spread person to person, the more interaction you’re having, the more ability that virus has to spread,” Kasangra said.

The winter peak in cases began to drop off in January and February, when average cases started to slowly decline again.

The decrease also occurred when the COVID-19 vaccine was made available to the public — first to older populations, and then gradually to everyone, Kasangra and MacDonald said.

The decline also may have occurred when the holidays were over, and people were traveling and gathering less, MacDonald said.

“We’ve only gone through one season of it now, and we’ll see what happens in the future. Certain strains may start to behave differently as well, so we’ll learn more about that as it goes forward,” Kasangra said.

Is the current surge going to peak as high as the winter surge?

No, says MacDonald. While the surge will eventually peak, “We’re not going to see the same peaks based on the fact that we do have 47% of the total population of North Carolina vaccinated.”

Vaccinations were not widely available throughout November and December as winter cases surged, and were in short supply in January and February to select populations.

However, there are still a lot of people who can become infected with COVID-19.

MacDonald said 60% of the North Carolina population has some kind of immunity, either because they’ve already had COVID-19 or they’ve been vaccinated. This means that 40% of the state is immunonaive “and therefore highly susceptible to getting infected.”

“So there’s still a lot of people who can get infected, and therefore, we will see an amplification and a growth of where we are right now and the number of cases per day,” she said.

This story was originally published August 10, 2021 at 10:00 AM with the headline "NC’s COVID surge is steeper than it was months ago. Here’s why this wave is different.."