SOUTHEASTERN N.C. — The more contagious a virus, the more people need to be immune for it to reach an endemic stage. Some local health officials suggest that phase of the Covid-19 pandemic could be near.
What that looks like is an almost total immunity rate and lower numbers of hospitalized patients, with infection rates somewhat static, not rising or falling. The real goal is to live with the virus so that it doesn’t disrupt daily life.
Data keeps shifting as Covid evolves. Whereas last year experts believed herd immunity, based on the beta variant, would have to reach 70% of the population, Wilmington Health chief epidemiologist Dr. Paul Kamitsuka said in light of the highly contagious omicron variant, that rate needs to be closer to 95%.
“We’re starting to get toward those levels, if you combine infection-acquired immunity and vaccine-acquired immunity,” he said. “But this is one of those situations where having had the vaccine is significantly more protective than having the infection itself.”
Following a recent surge of omicron, case numbers are trending downward but with so much still unknown about the constantly mutating and evolving virus, only time will tell.
Dr. Kamitsuka explained a virus, by nature, looks to survive by continually infecting new hosts.
“If it kills off all its victims, it’s not going to survive,” he said. “What the virus has done through random mutation is ‘learned’ how to infect people without killing them, thereby continuing to spread in nature and ultimately survive.”
For New Hanover Regional Medical Center’s chief clinical officer, Dr. West Paul, getting Covid-related hospital numbers to a more manageable place is key.
“With an endemic, it doesn’t go away,” he said. “But it may lessen the number [of patients] we’re seeing and that would be great.”
Currently, the hospital is averaging 100 or so people a day, though Paul would like to see it fall to 10 or 20. He said 90% of the hospital’s Covid-19 patients are unvaccinated or not boosted. Out of those 100 patients, 83% came in for Covid-related symptoms and 17% were admitted for other reasons and happened to test positive, he added.
The number of patients winding up in intensive care with omicron, about 10%, is lower than the 35% seen last summer during the delta variant surge, he noted. Still, nearly all Covid ICU patients wind up on ventilators.
“We have another 50 or 60 off isolation but still in house being treated for Covid symptomology — just off isolation,” Paul said. “Those are in recovery but may still need oxygen, are intubated or have significant illness that they cannot be discharged.”
Similar trends as the flu
Many have compared the Covid-19 pandemic with the multiple influenza pandemics before. For over a century, the flu has mutated; medical professionals can map what the future of living with Covid might look like based on history.
“[The 1918 pandemic] went on for a couple years then sort of petered out and became the endemic H1/N1 virus,” Kamitsuka said. “The same thing appears to be happening with Covid. Over the next weeks or months, it’s going to recede into something more like the flu.”
Though contagious, omicron already is proven to be less lethal — and the more people who obtain immunity, the less dangerous the virus becomes.
“Every year you have flu season, and it will kill off 30,000 people yearly, but it’s mostly secondary to exacerbating chronic medical conditions,” Kamitsuka said.
The difference is, the flu right now is seasonal, while Covid has not proven to be, Paul said. It still requires a different vaccine annually to stave off its invasion.
“It is nowhere near close to the mortality Covid causes, but we know flu vaccines have saved numerous lives, especially with the vulnerable populations,” he said. “Covid is much more deadly, order of magnitude more deadly, than the flu.”
Still, the process to track it may end up being similar to how the state currently receives preemptive warning of flu seasons.
N.C. Department of Health and Human Services’ newly appointed secretary — and Wilmington native — Kody Kinsley explained North Carolina uses syndromic surveillance, a collection and review of public health data, to catch early signs of illnesses to come. For the flu, hospitals track people who are admitted with flu-like symptoms and the data is compared with other hospitals to detect trends.
The state has instituted syndromic surveillance for Covid as well and is testing the wastewater of more than 20 facilities to track infection. This wastewater monitoring data will assist with determining the rate of infection and recently has been added to the Centers for Disease Control and Prevention’s Covid data tracker.
“People with Covid-19 shed viral particles in their stool,” according to a NCDHHS press release. “These viral particles are pieces of the SARS-CoV-2 virus, which causes Covid-19 when still intact. In wastewater, the particles are no longer infectious but can still be measured using sensitive laboratory techniques.”
North Carolina’s wastewater systems only cover 50% of the population but are tested twice weekly and reported to the state Covid dashboard.
“That’s really our early canary, if you will,” Kinsley said. “We watch carefully, work with the hospitals and protect the hospital capacity.”
Kinsely said hospital capacity is “the critical stop gap” for transmission. Having enough beds and infrastructure in place is key to being able to respond and get to an endemic state.
The omicron surge escalated much more quickly than delta. Paul said New Hanover Regional Medical Center didn’t see as many patients this time around as with the surge last summer into fall.
“This surge, we started in the low double digits to almost triple digits in a couple weeks. We did not see that with delta. It took five or six weeks to creep up,” Paul said.
The number of pediatric Covid cases also tripled or quadrupled with omicron, he explained.
In general, however, Paul said the surge is plateauing, which allows hospitals to serve additional patients.
Kinsley said in North Carolina omicron peaked the week of Jan. 21. Following the decrease in cases, hospitalizations should follow suit, he explained, but there is a lag.
“You get infected, you don’t end up in the hospital for several days,” Kinsley said. “It makes sense that, collectively, if the peak of cases was about a week and a half ago then perhaps we’ll see hospitalizations come down in another week or so.”
Locally, the percent positivity of Covid-19 tests has seen a steady drop over the past three weeks. During the peak of omicron, New Hanover County reported 811 cases per day on Jan. 19. As of Feb. 1, that dropped to 60 cases per day.
The county has reported 5,145 cases over the last 14 days, with a 36.6% positivity rate as of Feb. 3. This comes to approximately 367.5 cases a day.
Kamitsuka said New Hanover averaged two deaths per day during omicron — a vast difference from three to eight deaths a day during delta.
“That’s not trivial,” he said. “For God’s sake if everyone just wears the right masks — N95 and KN95 — it’s going to protect us all. Those not vaccinated or don’t wear the right masks, given how contagious omicron is, you’re playing Russian roulette with your life because it still can kill as we see everyday.”
Kinsley and officials at the state continue to push for vaccinations as the main protection against any Covid-19 surge. Right now vaccines and boosters are widely available for ages 5 and up; 65% of New Hanover County residents are fully vaccinated. Though younger children are currently unable to be inoculated, it could change within the next month. Pfizer submitted data for emergency-use, two-dose shots for babies ages 6 months and up to the Federal Drug Administration for approval.
While those who have had Covid-19 do have immunity resistance, it’s not as strong as what derives from the vaccine, Kamitsuka said.
Based on a study released by the CDC, people who had Covid and subsequently did not receive vaccines were 2.3 times more likely to get it again.
“If you’ve had Covid before, your immunity lasts for three months of being highly protective and then it trails off,” Kamitsuka explained. “For those who had vaccines, after about six months, it trails off.”
While boosters provide an even higher level of protection, the level and longevity are still unknown.
While Covid cases are on the down turn, Kinsley expressed those who aren’t vaccinated should do so, to ensure the best chance at reaching herd immunity: “Maybe some folks who were unvaccinated didn’t get Covid this time, but if we have another variant on the horizon, now’s the time.”
Early detection of the omicron’s “sibling” variant, BA.2 — or “stealth omicron,” as it’s become known — has not shown up in North Carolina yet, according to Kinsely. Still, officials are monitoring the situation.
A subvariant of omicron, Kinsley likened BA.2 to a “second cousin three times removed.” The secretary said they’ve kept a watchful eye on its impact in other places, particularly in Denmark where the subvariant has invaded the population.
When dealing with new variants, Kinsley said he and officials at the state health department assess it in three ways:
- Is it more contagious?
- Is it more severe?
- Is it powerful enough to bypass the immunity people have from the current vaccines, from having the virus, or from predecessor variants?
Early evidence indicates BA.2 may be up to 50% more transmissible because it’s spreading rapidly relative to the proportion of omicron cases.
“That’s not a foregone conclusion yet; there is still much we don’t know about it and we’re still a ways off from understanding how much more contagious it is,” Kinsley clarified.
He said the state labs analyze how antibodies perform against new variants and what the virus does to certain tissues in the body. Observing what happens as people show up to hospitals with an active infection provides additional empirical evidence.
Even if BA.2 is more contagious, Dr. Kamitsuka pressed that current immunity should provide equal protection to the subvariant.
“I’m optimistic that the next few months will look different from the past few months in terms of numbers of cases being much lower,” he said. ”Because of the levels of immunity in the population and also the changes in the virus itself.
“We just have to get through the next few weeks first.”
Being boosted will provide 92% protection, but more importantly, Dr. Paul said, it helps patients avoid hospitalization. And rarely does the hospital see a boosted patient with Covid-19, he added.
Right now, according to genetic sequencing on all positive Covid-19 tests in the state lab, 99% of cases are classified as omicron.
“All that to say, I am concerned about this [new] variant just as much as I am concerned about every variant and will always be concerned about variants,” Kinsley said. “But I’m not in a place where we need to be over-alarmed.”
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