COVID-19 Health 

Long-Term Effects of COVID-19 Infection


As the world enters Pandemic Year Two, data is showing that the long-term effects of COVID-19 infection are becoming a long-term problem.

By Kate Stone

Many individuals who caught and recovered from COVID-19 in 2019 are still suffering from troublesome long-term symptoms that are taking a lasting toll on their quality of life. In a recent study, Helen Y. Chu, M.D., from the University of Washington in Seattle and her team of researchers have taken a close look at recovered COVID-19 patients with persistent symptoms six to nine months after first falling ill.

Previous studies have documented persistent symptoms, also dubbed “long COVID,” in patients one to three months after the onset of the illness. This is the first study to look at patients up to nine months down the road. Patients in this study no longer tested positive for the novel Coronavirus, but were left with long-term effects of COVID-19 infection, or sequelae.

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Definition of sequelae

Sequelae (plural) refers to the aftereffects of a disease, condition, or injury.

Long-Term Effects of COVID-19

The people who participated in this study were 18 to 94 years of age. 57 percent were women. 6.2 percent were asymptomatic. 84.7% were outpatients with mild cases of COVID-19. 9.0 percent had moderate or severe disease requiring hospitalization.



Hypertension was the most common long-term effect of COVID-19 infection. The follow-up survey was completed up to 300 days after illness onset among participants who had contracted and recovered from COVID-19. Among participants with COVID-19, persistent symptoms of hypertension were reported by 26.6 percent of patients aged 18 to 39 years, 30.1 percent of patients aged 40 to 64 years, and 43.3 percent of patients aged 65 years and older.

Chronic Fatigue

According to this study, chronic fatigue is impacting 13.6 percent of COVID-19 survivors. The Mayo Clinic defines chronic fatigue syndrome (CFS) as, “a complicated disorder characterized by extreme fatigue that lasts for at least six months and that can’t be fully explained by an underlying medical condition. The fatigue worsens with physical or mental activity, but doesn’t improve with rest.

Continued loss of sense of smell or taste

Early in the COVID-19 pandemic, loss of the sense of smell emerged as a common symptom among people infected with the SARS-CoV-2 virus, even for people who didn’t show any other symptoms. Six to nine months later 13.6 percent of patients in this study have not yet recovered their sense of taste, smell, or both.

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Brain fog and beyond

Difficulty thinking through actions or performing some cognitive functions, commonly dubbed “brain fog” and some other symptoms have emerged as ongoing problems for former patients. In fact, 13 percent reported other symptoms, including 2.3 percent with brain fog. 7.9 percent reported negative impacts on at least 1 activity of daily living, with the most common being household chores.

This particular study was limited by a comparatively small sample size, single study location, potential bias from self-reported symptoms during illness episode, and some participant attrition. However, the researchers behind this study believe it to be the longest follow-up symptom assessment after COVID-19 infection conducted thus far. The results point to the health consequences of COVID-19 extending far beyond acute infection, even among those who experience mild illness. 

Read more about long COVID and cognitive functioning: Feeling Brain Fog? It Could Be in Your Blood

This study was published by JAMA Network Open. Funding was provided by the Bill and Melinda Gates Foundation.


Logue JK, Franko NM, McCulloch DJ, et al. (2021). Sequelae in Adults at 6 Months After COVID-19 Infection. JAMA Netw Open. 4(2):e210830. doi:10.1001/jamanetworkopen.2021.0830

The information contained in this article is for informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.


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