According to the study, of adults who have had Covid-19, 21.4% experienced at least one new or severely increased symptom three to five months post-infection compared to before infection. This was against 8.7% of uninfected people in the same time period, suggesting that one in eight Covid-19 patients (12.7%) in general population experience long-term symptoms due to Covid-19.
The study also looked at an individual’s symptoms both before and after the Covid infection and found some core symptoms of long Covid including chest pain, difficulties in breathing, pain when breathing, painful muscles, loss of taste and smell, tingling extremities, lump in throat, feeling hot and cold, heavy arms and/or legs, and general tiredness, it said.
The authors highlighted the need for more research into what causes long-term Covid-19 symptoms. Judith Rosmalen, from the University of Groningen and lead author of the study, stated that there is an urgent need for data informing the scale and scope of the long-term symptoms experienced by some patients after Covid-19 illness.
“However, most previous research into long Covid has not looked at frequency of symptoms in people who haven’t been diagnosed with Covid or looked at patients’ symptoms before the diagnosis of Covid.” In the study, researchers collected data by asking participants of population-based Lifelines Covid-19 Cohort to fill out digital questionnaires on 23 symptoms linked with long Covid.
The questionnaire was sent out 24 times to the same individuals between March 2020 and August 2021. 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.
The study was conducted on 76,422 participants. It was seen that the severity of symptoms plateaued at three months after infection with no further decline. Other symptoms that did not significantly increase three to five months after a Covid-19 diagnosis included headache, itchy eyes, dizziness, back pain and nausea.
Of the study participants who had submitted pre-Covid symptom data, the researchers found that 21.4% (381/1,782) of Covid-19-positive participants, compared to 8.7% (361/4,130) of the control group, experienced at least one increased core symptom at moderate severity 3 months or more after SARs-CoV-2 infection. This implies that in 12.7% of Covid-19 patients their new or severely increased symptoms three months post Covid can be attributed to SARS-CoV-2 infection.
