What are the long-term symptoms of COVID-19?

For most people, COVID-19 is a mild and transient disease, but some may develop persistent problems after the acute phase. Long-term symptoms have been reported previously following other infectious diseases, so it is no surprise that some patients experience long-term symptoms after COVID-19. It is already known that patients who are treated in intensive care for severe lung failure - regardless of the cause - may struggle with long-term functional impairment after discharge from the hospital.

Common symptoms

Among people with COVID-19 who were not admitted to hospital, the most commonly reported symptoms 6-12 months after the disease include

• impaired memory
• altered sense of taste and / or smell
• fatigue / tiredness, impaired ability to think and concentrate (so-called "brain fog")
• breathing difficulties.

Read more here:

• COVID-19: Post COVID-19 condition. Rapid overview.

People with COVID-19 who were admitted to hospital, especially those who received intensive care, have more frequent and more symptoms after 6-12 months than people who have not been admitted, and they seem to have a higher risk of being readmitted. The most common symptoms are fatigue / tiredness, breathing difficulties, anxiety and sleep problems, but also muscle weakness, headaches, pain, dizziness, depression and prolonged cough.

It is still uncertain how long the symptoms persist among people who have had mild to moderate disease courses. A Norwegian study of non-hospitalised patients in the rapid review found that people who had had COVID-19 reported a higher incidence of brain / nervous system and respiratory problems than non-infected people 12 months after the disease. The difference was greatest for altered smell and taste (COVID-19 17% compared to non-infected 0.3%), impaired memory (18% against 4%), breathing difficulties (11% compared to 1%) and fatigue (17% compared to 4%).

Risk factors for long-term symptoms after COVID-19

Women are more prone to long-term symptoms than men, regardless of whether they have been admitted to hospital or not.

People who have had a more severe acute COVID-19 disease course with a need for hospitalisation and intensive care, more symptoms at the time of diagnosis and who have underlying diseases, have an increased risk of persistent symptoms 6-12 months after COVID-19.

The rapid review included only one study of long-term symptoms after COVID-19 among children and adolescents, and this included children and adolescents who were admitted to hospital in Moscow.

Knowledge about long-term symptoms

There is a need for several larger studies with good control groups to gain more reliable knowledge about long-term symptoms. In this way, we can investigate how long-term symptoms after COVID-19 may differ from symptoms that non-infected people may also experience, for example, because of the measures during the pandemic.

The studies in the rapid review only applied to unvaccinated people. There is a need for studies examining the incidence of long-term sequelae after COVID-19 among vaccinated people compared with unvaccinated, and the risk of long-term sequelae after infection with the omicron variant.

In autumn 2020, the World Health Organization (WHO) launched the concept and diagnosis "Post COVID-19 condition". Meanwhile, we also received the diagnostic code U09 in ICD 10 "Post-infectious condition after COVID-19" for use in hospitals. Norwegian health authorities, including the Norwegian Institute of Public Health, now use the term "long-term sequelae after COVID-19".

Treatment / rehabilitation

Treatment or rehabilitation depends on the symptoms or problems presented.

The Norwegian Directorate of Health recommends that people who have had a mild or moderate disease course should consult their doctor if they have symptoms after four weeks that make it difficult to participate in daily life. The doctor will then consider the need for rehabilitation.

Patients with a severe disease course and longer stays in intensive care often have a greater need for rehabilitation. Patients with long-term problems after a mild to moderate disease course should also receive appropriate treatment and rehabilitation options.

• Guidelines from the Norwegian Directorate of Health on long-term sequelae and rehabilitation after COVID-19- In Norwegian