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  • A new study found that the likelihood of developing long COVID was significantly less after having the Omicron variant of COVID-19 compared to having the Delta variant of the disease.
  • The researchers looked at data from over 56,000 adults in the U.K.
  • Doctors are still learning about how long symptoms may last, but there are treatment options available.

Researchers from Kings College London have found that the Omicron variant of COVID-19 is less likely to cause long COVID than the Delta variant of the disease is.

According to their study published in the journal The Lancet, the odds of experiencing long COVID were between 20 to 50 percent less during the period that the Omicron variant of COVID-19 was dominant versus the Delta variant period, depending on age and time since vaccination.

Using data from the ZOE COVID Symptom study app, 56,003 UK adult cases were identified as first testing positive between December 20, 2021 and March 9, 2022 when the Omicron variant of COVID-19 was the dominant strain.

Researchers then compared these cases to 41,361 cases first testing positive between June 1, 2021 and November 27, 2021 when the Delta variant of COVID-19 was dominant.

They discovered that nearly 4.5 percent of Omicron-variant cases of COVID-19 were long COVID, compared to a roughly 11 percent of the Delta variant cases of COVID-19.

“We know that patients with more severe disease are more likely to have long COVID, and the Omicron wave lead to less severe symptoms and less hospitalizations than Delta,” Natalia Covarrubias-Eckardt, MD, medical director of the Inpatient Rehabilitation and the Post-COVID Rehabilitation Program at Providence St. Jude Medical Center in Orange County, California told Healthline.

However, the absolute number of people with long COVID was still higher in the Omicron-variant period due to the large numbers of people infected with the Omicron variant of COVID-19 from December 2021 to February 2022.

William A. Haseltine, PhD, former professor at Harvard Medical School and Harvard School of Public Health and author of Omicron: From Pandemic to Endemic : The Future of Covid-19, said at one point it was suspected that long COVID was actually a psychological condition.

“But those have been dispelled by the serious nature of some long-term symptoms, particularly neurological symptoms,” he said.

“The second thing we understand,” he continued. “Is that acute COVID-19 can cause serious permanent damage to organs.”

Dr. Haseltine said this includes damage to the brain and the heart, the lungs, liver, the pancreas, and the kidney.

“Another way to define long COVID is a series of symptoms that occur following COVID-19, following resolution of the virus two to three months after the virus is gone,” he explained.

According to Haseltine, when defined this way “you get somewhere between 30 and 50 percent of people have at least some long symptoms within three to six months.”

He emphasized that a much smaller fraction of infected people, from two to five percent, have very serious, life-altering symptoms extending for a year or more.

“Those include, in my mind, specific organ damage,” he noted. “Everyone is at risk of long COVID, as far as we know.”

Haseltine explained that an exception to this is a type of long COVID in which someone experiences organ damage.

“Organ damage is more likely associated with severe COVID-19 requiring hospitalization and in some cases intensive care unit admission,” he said.

But he emphasized that the “traditional symptoms” of brain fog, difficulty breathing, and extreme fatigue, aren’t associated with disease severity and almost anybody can develop those symptoms.

“Almost anybody can suffer those long consequences regardless of the severity or any other pre-existing condition that we know,” said Haseltine.

Haseltine confirmed that only one study he’s seen, shows that vaccination prior to breakthrough infection reduces the incidence of long COVID, but only slightly, about 15 percent.

“That means that of you have a breakthrough infection following vaccination and boosting, that you still can contract long COVID,” he said.

Haseltine believes this is most relevant in the current situation where the vaccinated population seems to be equally at risk of infection as the non-vaccinated population.

“That means that they are equally, that they’re basically unprotected from long COVID, but with a slight edge, like a 15 percent edge of protection,” he said.

Haseltine said this contrasts with more than 90 percent protection from serious disease and death that vaccines afford.

“Even at the height of the pandemic, only about one to two percent at the most, of people who were infected in the United States died,” he said. “Under those criteria, greater than one to two percent of people who are infected [after] having been vaccinated are very likely to experience lifelong complications of COVID-19, such as long COVID.”

He said this means brain damage, mental confusion, and fatigue.

“In some ways, the fatigue part of long COVID resembles chronic fatigue syndrome,” said Haseltine.

Haseltine thinks we’re going to find that as big as chronic fatigue syndrome (CFS) is, long COVID-associated chronic fatigue will be bigger.

“The rough estimate is 150 to 200 million Americans have been infected,” he said. “If you have two percent of that, that is a very large number.”

Haseltine also said there are fears that this will not only stress the medical community, but also the economy.

“There is some realization that long COVID symptoms are taking people out of the job market,” he said.

According to Dr. Covarrubias-Eckardt, treatment depends on the primary symptoms.

“For those with post-exertional malaise,” she said. “Pacing strategies are very effective.”

She said that people experiencing “brain fog” can be taught memory strategies and techniques to help compensate for the condition.

Asked if long COVID-19 eventually resolves for most people over time, Covarrubias-Eckardt said we’re still learning how long symptoms last.

“But we’ve seen many people improve and get back to their regular activities,” she said.

New research has found that the Omicron variant of COVID-19 carries significantly less risk of causing long COVID than the Delta variant of COVID-19 did.

Experts say the sheer number of people who could experience this condition carry severe implications for society.

They also say that doctors are still learning about how long symptoms may last, but there are treatment options currently available.