Friday, 9 Dec 2022

Long-term symptoms 23 months after SARS-CoV-2 infection

In a recent article posted to Open Forum Infectious Diseases, scientists analyzed coronavirus disease 2019 (COVID-19) symptoms lasting 23 months after the infection.

Study: Long COVID in the Long Run—23-Month Follow-up Study of Persistent Symptoms. Image Credit: Maria Sbytova/Shutterstock


More than 572 million confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases globally were reported over two and a half years into the COVID-19 pandemic. In addition, there are likely many more undetected COVID-19 cases. Meanwhile, numerous studies have shown that the long-lasting impacts of COVID-19, also known as long COVID, could significantly influence the global public health and healthcare burden. Nonetheless, the length of long COVID is still unknown, given most studies indicate that patients still have identifiable signs and symptoms at the time of their last evaluation about 12 months following infection.

In a prospective cohort of 180 mostly non-hospitalized cases, the present study's authors have previously detailed the prevalence of symptoms four months following SARS-CoV-2 infection, with more than half of the subjects experiencing persistent symptoms.

About the study

In the current prospective research, the scientists investigated the same study population they assessed earlier for four months for long-term COVID-19 symptoms for 23 months post-SARS-CoV-2 infection. 

The team invited all patients with confirmed COVID-19 in the Faroe Islands between March 2020 and April 2020 to participate in the study. Further, 180 subjects were interviewed via phone, and a validated questionnaire was used to evaluate their symptoms. Moreover, all study volunteers submitted informed consent before enrolling. The last follow-up was performed 19 to 23 months after illness onset, from November 2021 to January 2022.

The researchers asked questions on memory, recovery, and concentration only at the last follow-up since the chronic neurological effects of COVID-19 were unknown at the start of the SARS-CoV-2 pandemic. They also interrogated the participants regarding concentration and memory problems before COVID-19.


Overall, the study results showed that above one-third of COVID-19 patients from the spring of 2020 reported still having symptoms over two years following the acute infection. However, 76% of volunteers claimed full recovery, even some with at least one SARS-CoV-2 symptom during follow-up. Some people with chronic COVID-19 symptoms reported feeling complete recovery, whereas 2% reported feeling no recovery, and 22% reported no full recovery.

Fatigue, altered taste, and smell were the most common persistent symptoms similar to the acute phase and four-month follow-up. In addition, the common symptoms also included difficulties concentrating and remembering, which the team only asked the subjects at the last follow-up.

Most subjects mentioned mild or few symptoms, while 7% reported three or more, and 4% still had symptoms they rated as interfering with their everyday lives and severe, particularly noticeable for memory problems and fatigue. Chronic COVID-19 symptoms were less common in children than in adults. Besides, headache was the most prevalent symptom across children in the current study, and none reported impaired taste or smell.

Notably, the long COVID prevalence estimate offered by the present study was slightly lower yet was consistent with the few investigations examining long COVID one-year post-infection. All prior assessments demonstrated that the symptoms continue but not to the same extent. The team mentioned that the differences across studies might be due to methodological problems. Other possible causative elements included the subjective nature of symptoms and the influence of the cultural and psychological variables.

The study data were consistent with previously published research, which indicated that age and the number of acute symptoms were indicators of long COVID. Additionally, a trend was observed for higher body mass index (BMI) and smoking with long COVID. According to the correlation between the number of symptoms during the acute stage and the likelihood of long-term COVID, the acute phase was still a good indicator of COVID-19's long-term effects. This inference was applicable even in cases where the disease was relatively mild, like in the current study, which included participants who were primarily not hospitalized.


According to the authors, no other research has documented symptoms more than a year following COVID-19.

The study findings illustrated that 38% of the 170 patients observed for an average of 22.6 months had long COVID symptoms. The most common symptoms were fatigue, altered taste and smell, and trouble focusing and remembering. Older age and the number of symptoms during the acute phase were indicators of long COVID. The team stated that long COVID might require several months or even years to resolve.

In summary, the present findings highlight a significant clinical and public health issue, with around one-third of mostly non-hospitalized SARS-CoV-2 patients having persisting symptoms over two years after acute infection, albeit a relatively mild illness course at the initial phase. More studies are required to assess the long-lasting COVID-19 repercussions linked with newer viral variants and any potential protective benefits of COVID vaccinations.

Journal reference:
  • Helmsdal, G. et al. (2022) "Long COVID in the Long Run—23-Month Follow-up Study of Persistent Symptoms", Open Forum Infectious Diseases, 9(7). doi: 10.1093/ofid/ofac270.

Posted in: Medical Science News | Medical Research News | Disease/Infection News

Tags: Body Mass Index, Children, Chronic, Coronavirus, Coronavirus Disease COVID-19, covid-19, Fatigue, Headache, Healthcare, Infectious Diseases, Pandemic, Public Health, Research, Respiratory, SARS, SARS-CoV-2, Severe Acute Respiratory, Severe Acute Respiratory Syndrome, Smoking, Syndrome

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Written by

Shanet Susan Alex

Shanet Susan Alex, a medical writer, based in Kerala, India, is a Doctor of Pharmacy graduate from Kerala University of Health Sciences. Her academic background is in clinical pharmacy and research, and she is passionate about medical writing. Shanet has published papers in the International Journal of Medical Science and Current Research (IJMSCR), the International Journal of Pharmacy (IJP), and the International Journal of Medical Science and Applied Research (IJMSAR). Apart from work, she enjoys listening to music and watching movies.

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