Can Omicron Cause Long Covid?

Many public health officials are encouraged by the early evidence suggesting that Omicron variant infections tend not to cause severe illness as other coronavirus varieties. But another important question looms: whether infection with Omicron, including breakthrough cases in vaccinated people, can result in long Covid — the constellation of physical, neurological and cognitive symptoms that can last for months and impair people’s daily lives.

Scientists are still too young to know much about Omicron, vaccination, and long Covid. Research done before the pandemic did not yield any definitive clues. Here is a brief overview of what scientists know and the many unanswered questions.

Can Omicron cause long Covid?

The Omicron variant was only identified in November. It is not yet known how long symptoms can persist. It is not known if it can cause brain fog or extreme fatigue, as with previous viruses.

Recent reports suggest Omicron may cause less severe symptoms than other variants. However, Omicron’s basic symptoms are similar to those of other variants. This suggests that Omicron could have long-term effects.

Doctors, researchers, and patient-led groups caution that Omicron may not be more likely to cause long Covid if there are milder initial illnesses. Studies from earlier waves have shown that many people who had mild to moderate initial reactions to coronavirus infection were later diagnosed with long-lasting Covid.

Can vaccines prevent long Covid?

Maybe.

Vaccines are used to prevent serious illness or death from coronavirus infections. With some previous variants, vaccines seemed to reduce the likelihood of infection itself — and not getting infected is, of course, the best way to avoid long Covid. However, Omicron is a newer variant that has been proven to be more resistant to vaccines.

Studies of long-term Covid in vaccinated persons have largely focused on data from before the emergence and spread of the Delta variant. The results of these studies have been mixed.

One large study published in The Lancet Infectious Disorders was based on data from over 1.2 million British adults who received at least one dose (or more) of coronavirus vaccine. It was found that people who received two doses of vaccine and had breakthrough infections were half as likely to experience symptoms lasting more than 28 days. The study found that 5 percent of people with breakthrough infections reported these lingering symptoms, compared to 11 percent infected individuals in an unvaccinated group.

Another large study was published without peer-review and found a similar encouraging result. Arcadia, a data firm specializing in health care, and the Covid Patient Recovery Alliance (a collaboration of health experts in the public and private sectors) conducted the study. It analyzed records from approximately 240,000 coronavirus-infected patients between May 2021 and May 2021.

It was found that people who received a single dose of the Covid vaccine before they were infected were seven to ten times more likely to experience two or more symptoms of long Covid 12-20 weeks later. The study, which was led by Michael Simon, Arcadia’s director of data science, and Dr. Richard Parker, the firm’s chief medical officer, also found that people who received their first vaccine dose after contracting the coronavirus were less likely to develop long Covid than those who remained unvaccinated, and the sooner they were vaccinated after infection, the lower the risk of long-term symptoms.

However, results from another study that was not yet peer reviewed were less encouraging about vaccines’ ability to prevent long-term Covid. Researchers in the United Kingdom analysed electronic medical records from patients in the United States to conduct the study. It compared about 10,000 people who had received Covid vaccines with a similar number of people who had not been vaccinated against the coronavirus but did have a flu vaccine — an effort to limit the number of people in the study who might be considered vaccine hesitant or who generally had less healthy behaviors, the researcher said.

The study showed that the risk of developing long-term Covid symptoms was not reduced by having a coronavirus vaccination before being infected. Although there was some evidence that vaccined people were less likely to experience long-term symptoms like cognitive symptoms and abnormal breathing, the authors did not conclude statistically.

The authors suggested that it was possible that, because their data relied upon electronic health records, the study might only have captured patients with the most severe symptoms and not a wider range who did not seek medical attention for their symptoms.

Are vaccines possible if you have Covid for a long time?

Before the introduction of the contagious Delta variant of vaccines, patients with long Covid found that their symptoms such as joint pain, fatigue, and brain fog improved after being vaccinated. Many people felt no improvement in their symptoms and a few reported feeling worse.

The Office for National Statistics in the United Kingdom discovered that a first dose vaccine reduced the likelihood of long-term Covid symptoms in people aged 18 to 69 who reported their symptoms between September 2021 and February 2021. The study revealed that the odds of getting a second dose were 9 percent lower.

Some researchers believe that vaccines might be scientifically sound and could help those with long Covid.

Experts are still not sure what causes long Covid. Different symptoms may have different causes. One theory is that the condition could be due to residuals of the virus or its gene material, inflammation or blood circulation problems caused by an overactive immune system that is unable shut down, or both.

Yale immunologist Akiko Ichasaki believes that vaccines can provide lasting relief to people with symptoms caused by remnants of the virus. If the antibodies produced by vaccines are destroyed, Akiko says. However, she stated that vaccines might not provide lasting relief to people who have symptoms that may be due to an immune response similar to an autoimmune disease.