COVID Vaccines Reduce Long COVID Risk, Study Shows

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The risk of developing long COVID has decreased over the course of the COVID-19 pandemic. Researchers attributed about 70% of this reduced risk to vaccines and 30% to changes in the virus over time and improved detection and management, according to recent research published today in the New England Journal of Medicine.

A team of researchers from Washington University School of Medicine in St. Louis led by Ziyad Al-Aly, M.D., a Washington University clinical epidemiologist, used health records from the Department of Veterans Affairs to identify 441,583 veterans who had COVID-19 between Mar. 1, 2020, and Jan. 31, 2022. They also used about 4.7 million records of uninfected veterans as the control group.

Researchers separated everyone into eight groups, three control cohorts and five COVID-19 cohorts. The control group consisted of the those who did not have the original COVID-19 strain in 2020, the delta variant in 2021 or the omicron variant in 2022.

The COVID-19 group was made up of those who were not vaccinated during the pre-delta, delta, and omicron era and were infected as well as those who were vaccinated and were infected during the delta or omicron era.

Long COVID-19 rates were the highest in the group with the original strain, which makes sense because there was no vaccine available at this time.

In those with COVID-19, long COVID incidence during first year after infection was:

• 10.4% in the pre-delta era
• 9.5% in the delta era
• 7.8% in the omicron era

In the vaccinated, long COVID-19 rates were:

• 5.3% in the delta era
• 3.4% during the omicron era

“Among vaccinated persons, nearly all disease categories showed a lower cumulative incidence of [Long COVID-19] and none showed a higher cumulative incidence of [Long COVID-19] during the omicron era than during the delta era,” Al-Aly writes in the study. “These findings suggest that vaccine uptake will be key to maintaining the lower cumulative incidence of [Long COVID-19] relative to earlier phases of the pandemic.”

Long COVID occurs in about 10% of people, no matter the severity of the initial infection, but it is more common in people who were hospitalized for COVID-19, according to the National Institutes of Health. It is characterized by a variety of symptoms that may be the same or different from the COVID-19 infection. Patients could experience symptoms anywhere in the body. They are commonly chronically fatigued and may experience infertility, shortness of breath, digestive issues, hair loss and joint pain to name a few. Symptoms can last days, weeks, months or even years. To date, the World Health Organization (WHO) estimates there have been a total of 7.6 million cases worldwide. In this study, health outcomes were measured using 10 categories: cardiovascular, coagulation, hematologic, fatigue, gastrointestinal, kidney, mental health, metabolic, musculoskeletal, neurologic and pulmonary.