1 in 8 SARS-CoV-2 patients develop long COVID symptoms: Lancet study

One in eight adults who are infected with the SARS-CoV-2 virus experience long term symptoms due to COVID-19, according to a large Dutch study published on Friday in The Lancet journal.

The study provides one of the first comparisons of long-term symptoms after SARS-CoV-2 infection, called 'long COVID', with symptoms in an uninfected population, as well as those in individuals both pre- and post-COVID-19 infection.

The inclusion of uninfected populations enables a more accurate prediction of long-term COVID-19 symptom prevalence as well as improved identification of the core symptoms of long COVID.

The study looked at the symptoms most often associated with long COVID, including breathing problems, fatigue and loss of taste and smell, both before a COVID-19 diagnosis and in people who have not been diagnosed with the disease.

The researchers collected data by asking participants to regularly fill out digital questionnaires on 23 symptoms commonly associated with long COVID.

The questionnaire was sent out 24 times to the same individuals between March 2020 and August 2021, meaning participants who had COVID-19 during this time were infected with the SARS-CoV-2 Alpha-variant or earlier variants.

Most of the data was collected before the COVID-19 vaccine rollout in The Netherlands so the number of vaccinated participants was too small to analyse.

Of 76,422 participants, 4,231 participants who had COVID-19 were matched to 8,462 controls taking account of sex, age and time of completing questionnaires that indicated a COVID-19 diagnosis.

The researchers found that several symptoms were new or more severe three to five months after having COVID-19, compared to symptoms before a diagnosis and to the control group, suggesting these symptoms can be viewed as the core symptoms of long COVID.

The core symptoms recorded were chest pain, difficulties breathing, pain when breathing, painful muscles, loss of taste or smell, tingling hands and feet, a lump in throat, alternately feeling hot and cold, heavy arms or legs and general tiredness.

The severity of these symptoms plateaued at three months after infection with no further decline, according to the researchers.