Study: Some Individuals Report Long-Term Effects Following Mild COVID-19

Although it is known that many patients hospitalized with COVID-19 report persistent long-term symptoms, there is not much knowledge regarding long-term outcomes among individuals with mild COVID-19.

The results of a recent study suggest that even individuals with mild COVID-19 experienced long-term effects for several months after infection onset.¹

The COMMUNITY study, published in JAMA and conducted by investigators at Danderyd Hospital and Karolinska Institute in Sweden, intended to examine long-term immunity after COVID-19 infection. Health care professionals at Danderyd Hospital in Stockholm, Sweden, were asked to participated between April 15, 2020 and May 8, 2020. The study was limited to approximately 2000 participants because of testing restrictions.¹

For the first phase, blood samples were collected from 2149 hospital employees, of whom 19% had antibodies against SARS-CoV-2. Blood samples were collected every 4 months since then. Study participants also responded to questionnaires regarding long-term symptoms and their impact on quality of life. At the 8-month follow-up, participants reported via smartphone app the presence, duration, and severity of 23 predefined symptoms associated with COVID-19. This group consisted of 323 health care workers and was compared with 1072 health care workers who did not have COVID-19 during the study period.¹

Overall, 26% of those who had COVID-19 previously, compared with 9% in the control group, had at least 1 moderate to severe symptom that lasted more than 2 months. Moreover, 11%, compared with 2% in the control group, had a minimum of 1 symptom with negative impact on work, social, or home life that last at least 8 months.¹ 

Based on the responses, the most common long-term symptoms were loss of smell and taste, fatigue, and respiratory problems. However, the investigators wrote that they did not observe an increased prevalence of cognitive symptoms such as brain fatigue, memory, and concentration problems or physical disorders such as muscle and joint pain, heart palpitations, or long-term fever.^1,2

“Despite the fact that study participants had a mild COVID-19 infection, a relatively large proportion report long-term symptoms with an impact on quality of life,” Sebastian Havervall, deputy chief physician at Danderyd Hospital and PhD student in the project at Karolinska Institutet, said in a statement.² “In light of this, we believe that young and healthy individuals, as well as other groups in society, should have great respect for the virus that seems to be able to significantly impair quality of life, even for a long time after the infection.”

The investigators noted that limitations of the study include the possibility of recall bias and the subjective rating of symptoms. Furthermore, they concluded that further research is needed to determine the mechanisms underlying COVID-19–related long-term effects.¹

References

1. Havervall S, Rosell A, Phillipson M, et al. Symptoms and functional impairment assessed 8 months after mild COVID-19 among health care workers. JAMA. April 7, 2021. doi: 10.1001/jama.2021.5612
2. One in ten have long-term effects 8 months following mild COVID-19. News Release. Karolinska Institutet; April 7, 2021. Accessed April 8, 2021. https://news.ki.se/one-in-ten-have-long-term-effects-8-months-following-mild-covid-19