In a recent study published in eClinicalMedicine, researchers compared symptom profiles between individuals with prior coronavirus disease 2019 (COVID-19) and those with other acute respiratory infections (ARIs).
Study: Long-term symptom profiles after COVID-19 vs other acute respiratory infections: an analysis of data from the COVIDENCE UK study. Image Credit: Prostock-studio/Shutterstock.com
Long COVID, the post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, can be defined as ongoing or new symptoms that persist more than four weeks post-infection.
It is estimated that ≥ 10% of SARS-CoV-2-infected individuals have long COVID, with much higher incidence among hospitalized individuals.
Post-acute infection syndromes often remain undiagnosed due to diverse symptoms and the lack of diagnosis tests. Further, research on post-acute sequelae of SARS-CoV-1, influenza, and Middle-East respiratory syndrome (MERS) has been limited to those with severe illness. In contrast, long COVID has been studied in individuals with all severity levels.
About the study
In the present study, researchers compared symptom profiles between people with prior COVID and those with prior non-COVID ARIs. Eligible subjects were United Kingdom (UK) residents aged 16 or older at enrolment.
Online questionnaires were administered to obtain information on COVID-19 test results, symptoms, vaccination status, and long COVID.
Participants had to complete a baseline questionnaire at enrolment and follow-up questionnaires every month after that. The study included non-vaccinated participants who completed the follow-up questionnaire in January 2021. Participants were stratified as having had COVID-19, non-COVID-19 ARI, or no infection.
SARS-CoV-2 infection was defined as a positive SARS-CoV-2 swab or antibody test. Non-COVID-19 ARI was described as a self-report or hospital diagnosis of common cold, influenza, pneumonia, pharyngitis, tonsillitis, bronchitis, ear infection, or other lower/upper respiratory infections. The prevalence and severity of 16 COVID-19 symptoms were assessed.
Breathlessness was measured with the Medical Research Council (MRC) Dyspnea scale; fatigue was evaluated with the Functional Assessment of Chronic Illness Therapy (FACIT) score; depression and anxiety were determined using the Patient Health Questionnaire (PHQ)-4; health-related quality of life (HRQoL) was assessed using EQ-5D-3L. The team performed latent class analyses (LCAs) to explore symptom clusters.
The study included 10,171 individuals in the analysis. A higher majority of participants were White and female. Nearly 13% of participants had prior COVID-19, and 4.6% had prior non-COVID-19 ARIs.
In general, COVID-19 subjects were infected earlier than those with ARIs. SARS-CoV-2-infected individuals were more likely to have been hospitalized during infection.
The prevalence and severity of symptoms among COVID-19 subjects were higher than those without (any) infection, irrespective of whether the infection occurred more than 12 weeks before.
Likewise, individuals with other ARIs also had increased symptom prevalence and severity relative to those with no infection, except for joint/muscle pain, hair loss, and problems with sense of smell/taste.
COVID-19 subjects had increased odds of problems with sense of taste/smell and dizziness or lightheadedness compared to those with other ARIs. COVID-19 subjects infected > 12 weeks prior were less likely to have cough or problems with sense of smell/taste and had lower dyspnea than those infected 4-12 weeks before.
COVID-19 subjects with a more severe infection had increased prevalence and severity of ongoing symptoms. The LCA models for COVID-19 revealed three symptom severity classes – mild (45% of participants), moderate (32%), and severe (22%). The mild class generally had low symptom prevalence and severity, with sleep problems being the most prevalent.
The moderate class showed a slightly higher probability of having all 16 symptoms but had a larger increase in sleep problems, PHQ-4 score, joint/muscle pain, and difficulty concentrating. The severe class showed a marked increase in symptom prevalence and severity, with the largest increases in dizziness, memory problems, and difficulty concentrating.
Participants were more likely to be frontline workers, comorbid, overweight/obese, female, and socioeconomically deprived with increasing symptom severity, and were more likely to report having long-term COVID with increasing severity of ongoing symptoms.
The LCA models for other ARIs revealed three classes – mild (40% of ARI subjects), moderate (38%), and severe (22%).
The LCA models for no infection also yielded two classes – mild (56%) and severe (44%). Participants with other ARIs or COVID-19 had a higher probability of all symptoms, especially cognitive problems, than those without (any) infection.
Notably, COVID-19 subjects had an increased probability of reporting memory problems, hair loss, problems with sense of smell/taste, and difficulty concentrating than those with other ARIs.
The study found that prior COVID-19 was associated with increased symptom prevalence and severity and lower HRQoL. This increased burden lingered more than 12 weeks post-acute infection.
COVID-19 subjects were likelier to report dizziness/lightheadedness and problems with sense of smell/taste than those with other ARIs, with marginal differences in HRQoL measures and other symptoms.
COVID-19 subjects were also more likely to report having long COVID as the severity of ongoing symptoms increased.
Taken together, both COVID-19 and other ARIs were associated with higher prevalence and severity of most symptoms and lower HRQoL relative to no infection. Further, with increasing research into long COVID, the post-acute burden of other ARIs should be investigated to ensure that affected individuals can access treatment.