Health specialists see state moving toward endemic response to virus from News-Review

By Paul Welitzkin

GAYLORD — In February, California became the first state to formally shift to an endemic approach to the coronavirus. Three medical/health officials said Michigan may eventually adopt the same strategy for the disease.

Diseases are endemic when they occur regularly in certain areas according to established patterns, while a pandemic refers to a global outbreak that causes unpredictable waves of illness.

Dr. Christopher Ledtke, an infectious disease specialist with Munson Healthcare, said recently that Michigan is heading towards the endemic, but is not there yet.

“Endemic implies that the virus will continue to circulate but at levels that are more manageable,” he said.

Dr. Teena Chopra, a professor of infectious diseases at the Wayne State University School of Medicine in Detroit, said the state is not yet in the endemic phase but is moving in that direction.

“The switch from pandemic to endemic is not an on/off switch. It is a slow transition and depends on many factors including the susceptibility of the population, immunity, new variants, etc. Even after we are in the endemic phase, there can be outbreaks, hospitalizations and deaths,” she said.

Dr. Peter Gulick is a professor of medicine at the Michigan State University College of Osteopathic Medicine and an infectious disease specialist. He said an endemic status is a “constantly moving target but in order for you to be in an endemic the COVID cases need to have stabilized. As far as (the) last few days cases as well as hospitalizations and deaths have stabilized, but we will need more time to be sure we don’t have any more surges. So most experts are still cautious about saying we are in an endemic yet,” he said.

Joshua Petrie, an associate research scientist at the Marshfield Clinic Research Institute in Wisconsin and a former professor in the department of epidemiology at the University of Michigan School of Public Health, said California’s plan takes a long-term view in managing the virus “recognizing that there is a lot of uncertainty about what the virus will look like in the future and that there won’t be a clear line between pandemic and endemic. I think this sort of long-term strategy is useful, and I’m sure a lot of states are finalizing similar plans,” he added.

Petrie added that an endemic will likely include a targeted response, just as other phases of the pandemic has.

“We’ve seen responses become more targeted throughout the pandemic. In Michigan there were the stay home orders early on, then broad mask mandates during later surges, followed by more targeted masking requirements. Throughout, these responses have also included targeted outbreak response, testing, surveillance, and vaccination programs. I think these responses will continue to become more targeted and focused on preventing outbreaks and rapidly responding to local outbreaks to minimize impact and preserve health care capacity,” Petrie said.

Chopra added that “We first need to define what endemic means for (the disease).”

“We can define that when we start seeing a pattern (such as) is there a seasonality or new variants? This is going to help us prepare,” she said. “We need to have resources in the form of (the) right surveillance tools and vaccines to be ready for what is coming just like we plan every year for the flu.”

Gulick said an endemic response will be when the condition has stabilized with a decrease in cases and usually occurs when the vast majority are properly immunized with either vaccine and/or natural immunity.

“Currently we are 66% with one vaccine and 59% fully vaccinated, which doesn’t necessarily mean the booster which is right now protecting us from omicron. With an endemic we just have to try to immunize as many as possible,” Gulick said. “Influenza is a good example of endemic as every year we have minor surges but the majority of infection is controlled as we have vaccinations as well as oral therapy for the virus. In a pandemic, the disease is still not controlled globally, which is still occurring in pockets like Africa and India, and so new more aggressive variants will continue to occur. To control this we will need to vaccinate much more along with natural immunity to get better control.”

According to the Mayo Clinic, herd immunity occurs when a large portion of a community becomes immune to a disease, making the spread of disease from person to person unlikely. As a result, the whole community becomes protected — not just those who are immune.

“By strict definition, herd immunity is the level of immunity in a population where sustained transmission of a disease is no longer possible,” said Petrie. “I think many people were thinking this way when vaccines first became available; that we could totally stop the pandemic. Waning immunity and variant emergence has of course complicated that. That said, the more immunity there is in a population, the fewer infections and severe outcomes there will be not only among vaccinated individuals, but also their unvaccinated contacts. I think this latter concept is certainly important to long term management of SARS-CoV-2.”

Gulick said herd immunity is still a worthy goal.

“The concept of herd immunity is still good where we need to get a certain amount of a population immune so the virus has little more to infect and less chance for variants and major surges,” he added.

Chopra said herd immunity is important.

“It is a combination of natural infection and immunity through vaccination and is very important to keep our hospitals from being overwhelmed,” she said.

Gulick believes that vaccinations and booster shots will remain important in the endemic stage.

“The big question is the ability of COVID to cause variants that are more transmissible, more virulent like delta and more able to evade the immune system and vaccine induced immunity. This is the big question. So, yes at this time vaccines and boosters are important especially in the immune compromised patients which may still only get partial immunity and have infection with new variants,” he added.

Petrie agrees with Gulick.

“We saw hospitals fill up, primarily with unvaccinated individuals, during the omicron surge,” Petrie said. “Individuals who had a booster were 90% less likely to be hospitalized than unvaccinated during the omicron surge. Continuing to prevent severe COVID-19 will remain a priority. I would expect additional boosters will eventually be necessary, and updates to the vaccine may be needed in the future if new variants emerge.”

Chopra said in addition to vaccines and booster shots, masks will play a prominent role in the endemic response.

“Masks are also very important (as) they prevent transmission. Even with endemic disease, if you are at high risk and are in a crowded place, masks will be protective against transmission,” Chopra said.

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