An estimated 12.7% of patients infected with SARS-CoV-2 will experience persistent COVID-specific symptoms between 90 to 150 days after COVID-19 infection, according to study findings published in the Lancet.
Prior research that has assessed the likelihood of post-COVID-19 symptoms has lacked the following: an adequate control group, a measure of the prevalence of somatic symptoms in a control group without COVID-19 infection, an assessment of whether somatic symptoms were present before COVID-19 infection, and research in a non-clinical setting that could be applied to the general population.
Researchers of the current study sought to report the nature and prevalence of post-COVID-19 symptoms while taking into account somatic symptoms present in individuals before infection and comparing symptom dynamics in individuals without COVID-19 infection during the pandemic.
For the study, researchers conducted a prospective, population-based, observational, cohort study using 24 data points from the Lifelines COVID-19 cohort study obtained between March 31, 2020 and August 2, 2021 in the northern region of the Netherlands.
They analyzed the long-term symptoms of 4231 people after COVID-19 infection and matched them to 8462 people in the control group. They adjusted for symptoms experienced before COVID infection by excluding reports on symptom severity a week prior to COVID diagnosis as these symptoms may have been related to COVID, prompting people to seek out a COVID diagnosis. They also excluded participants who did not have any baseline information on symptom severity prior to COVID infection.
People participating in the study completed digital questionnaires gathering data on 23 COVID symptoms. Every 2 weeks, the patients repeated the questionnaires to assess their symptoms over the past 7 days.
After adjusting for pre-COVID symptoms and restricting post-COVID symptoms to known core symptoms of COVID, 381 (21.4%) of 1782 people who were COVID-positive reported at least 1 symptom that increased to moderate severity 90 to 150 days after infection compared with 361 (8.7%) of 4130 control individuals (P <.0001) during the same period.
Taking the difference between groups, 12.7% of patients with COVID-19 with increased severity of core COVID symptoms at least 3 months after infection experienced long-term somatic symptoms solely attributable to COVID-19.
The most common persistent symptoms following COVID infection included:
- Chest pain,
- Pain with breathing,
- Painful muscles,
- Body temperature fluctuations (hot to cold feelings),
- Heaviness or tingling in the extremities,
- General fatigue, and a
- Lump in the throat.
Symptoms such as dizziness, headaches, nausea, back pain, and itchy eyes did not significantly increase in severity at 90 to 150 days after COVID. Symptoms such as runny nose, wet and dry coughing, sneezing, fever, and sore throat returned to pre-COVID severity after 50 days, more reflective of acute COVID.
“Increased knowledge on both the nature of the core symptoms and the prevalence of post-COVID-19 condition in the general population represents a major step forward in our ability to design studies that ultimately inform an adequate healthcare response to the long-term sequelae of COVID-19,” the researchers stated.
They added, “Further research that distinguishes potential mechanisms driving post-COVID-19-related symptomatology is required.”
Study limitations included the possibility of asymptomatic COVID cases, the use of the date on the first questionnaire after COVID diagnosis as the date of diagnosis (which may not reflect the true date of diagnosis), and the use of data from the Lifelines COVID-19 cohort study. Since the Lifelines study was conducted at the beginning of the pandemic, it did not assess symptoms, such as post-exertional malaise and brain fog, which were identified later during the pandemic. Additionally, this study did not evaluate individuals younger than 18 and only included people from northern Netherlands, so the results may not apply to pediatric cases or people living outside of the region.
Ballering AV, van Zon SKR, Olde Hartman TC, Rosmalen JGM, for the Lifelines Corona Research Initiative. Persistence of somatic symptoms after COVID-19 in the Netherlands: an observational cohort study. Lancet. Published online August 6, 2022. doi:10.1016/S0140-6736(22)01214-4