This evidence synthesis has been compiled by members of the CITF Secretariat and does not necessarily represent the views of all CITF members.

By Jeanie Quach

More research is being conducted to assess “long COVID”, defined as symptoms persisting for weeks to months after recovering from COVID-19. A study published in JAMA studying Swedish health care workers found that the most common long-lasting symptoms were the loss of taste and smell, fatigue, and shortness of breath. Meantime, in an Italian report published in Acta Paediatrica, researchers found long COVID affects children much like adults.

Eight-month assessment of health care workers after mild COVID-19

Studies on the long-term outcomes among individuals with mild COVID-19 are still limited. A cohort study involving 1,400 health care workers recruited between April 15 and May 8, 2020 was conducted in Stockholm, Sweden to assess COVID-19 related long-term symptoms up to eight months after infection. Some participants had had mild COVID-19 and others, part of the control group, had no evidence of prior infection. Blood was collected four and eight months post-COVID and questionnaires asking about demographics, symptoms, disease severity, and any chronic diseases were obtained at baseline. Participants self-reported the presence, duration, and severity of 23 predefined symptoms at the 8-month follow-up. Those that had at least one symptom for two months rated the effect of these symptoms on their daily lives.

About 26% of participants who had had mild COVID-19 reported at least one moderate to severe symptom lasting for at least two months, compared to only 9% of participants who had no evidence of prior infection. At the 8-month follow-up, 15% of participants who had had COVID reported at least one moderate to severe symptom, compared to 3% of non-COVID participants. The most common symptoms, lasting for up to two months in the COVID positive group, were the loss of taste and smell, fatigue, and shortness of breath. The participants who had had COVID reported much higher disruptions to their work, social, and home life than participants who had no evidence of prior infection. Less frequently reported symptoms including headache, palpitations, concentration and memory impairment, as well as muscle and joint pain also contributed to the loss of productivity.

The authors conclude that health care workers with mild COVID-19 report a diversity of symptoms that disrupt their daily lives and they can last up to eight months.

Havervall S, Rosell A, Phillipson M, Mangsbo SM, Nilsson P, Hober S, Thålin C. Symptoms and functional impairment assessed 8 months after mild COVID-19 among health care workers. JAMA. 2021 Apr 7. doi: 10.1001/jama.2021.5612

Children also experience persistent symptoms following COVID infection

As researchers are only beginning to learn about long COVID, there is even less data on long COVID in children. A brief report in Acta Paediatrica talks about persistent symptoms in Italian pediatric patients with previously diagnosed COVID-19. The cohort of 129 children diagnosed with COVID-19 were enrolled and interviewed to determine the duration of symptoms. About 66% of children had at least one persisting symptom 60 to 120 days after their initial COVID-19 diagnosis. About 43% of children still reported the presence of these symptoms after 120 days. The most frequent symptoms included sleep disturbances, pain and chest tightness, nasal congestion, fatigue, muscle and joint pain, and concentration difficulties.

Although this is a single-centre study with a small sample size, the findings indicate that symptoms do persist for children, as they do in adults.

The authors highlight the importance of conducting further large-scale studies, with healthy controls and objective clinical assessments, to reduce the impact of COVID-19 on children’s health and development.

Buonsenso D, Munblit D, De Rose C, Sinatti D, Ricchiuto A, Carfi A, Valentini P. Preliminary evidence on long covid in children. Acta Paediatrica. 2021 Apr 9. doi: 10.1111/apa.15870

Read a summary of earlier studies on long COVID here.