The range, severity, and duration of these post-COVID symptoms are not the same for everybody. While some eventually feel better over time, others simply do not see improvement.

A recent study published in the Annals of Clinical and Translational Neurology found that non-hospitalized patients with long COVID may experience various symptoms and compromised quality of life 11 to 18 months after the initial infection, with an average of about 14.8 months.

The researchers evaluated patients about six to nine months after their initial visit to Northwestern Medicine Neuro COVID-19 Clinic, and reported that the frequency of several symptoms had no significant changes between the first and follow-up evaluations.

“We asked the question everyone is interested in: How long is long COVID?,” Igor Koralnik, MD, study author and chief of Neuroinfectious Diseases and Global Neurology at Northwestern Medicine, told Verywell. “This is the longest follow-up study on neurologic symptoms in non-hospitalized patients anywhere in the world and it shows that most symptoms persist on average 15 months from disease onset.”

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What Do the Findings Mean?

Although some symptoms did not change after recovering from the initial COVID-19 infection, the findings showed that dysgeusia (altered sense of taste) and anosmia (loss of smell) mostly went away.

But the prevalence of heart rate and blood pressure variation, as well as gastrointestinal symptoms, increased overall. A different study published in Nature Medicine also found that people who got COVID-19 are at risk of developing irregular heart rhythms, even among those who were not hospitalized during the acute phase of the disease.

“These results suggest that there is a late development of dysfunction of the autonomic nervous system—dysautonomia—in these patients,” Koralnik said.

Researchers have yet to find out the reason behind this dysfunction in the body. It is unclear why around a third of infected patients develop long COVID, and there may be an autoimmune predisposition to it, he added.

Long-term follow-up is critical to determine how COVID-19 symptoms change over time, according to David J. Cennimo, MD, FACP, FAAP, an associate professor of medicine and pediatrics in the division of infectious diseases at Rutgers New Jersey Medical School.

The myriad of heart complications, such as palpitations, were underestimated earlier in the pandemic, Cennimo added. “We need to be thoughtful in monitoring patients for long-term cardiac complications," he said.

Does Vaccination Prevent Long COVID?

Cennimo said some limited data have suggested that vaccination “can improve the symptoms of long COVID.”

However, COVID-19 vaccinations did not make a difference in long COVID symptoms in the new study.

“In our study, 77% of patients got vaccinated between the first and second visit,” Koralnik said. “Vaccination had a neutral effect on the symptoms: no significant improvement or deterioration. We encourage all our patients to get vaccinated and boosted according to CDC recommendations.”

Only 52 patients were able to complete the follow-up study, which could have reduced the accuracy in detecting differences between people who tested positive for COVID and the control group that tested negative.

A new study at the BMJ suggests that vaccination after getting COVID-19 may reduce the risk of long COVID for at least several months after getting the shot, but a causal relationship has yet to be established.

The overall effect of vaccination against long COVID symptoms still needs to be studied. It’s also possible that vaccination might not have any effect at all.

Regardless, experts recommended that everyone get vaccinated and boosted against COVID-19 to reduce the risk of hospitalization and death.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.