Unvaccinated individuals who had mild COVID-19 were at increased risk for some sequelae outcomes, such as anosmia and dysgeusia, respiratory conditions, and concentration and memory conditions. However, most symptoms were found to be resolved within a year of diagnosis, especially for younger patients. These are the findings of a nationwide, retrospective cohort study published in BMJ.
Acute SARS-CoV-2 infections have been associated with multiple long-term sequelae conditions, however, to date it remains unclear whether mild COVID-19 may also be associated with risk for long-term sequelae.
Researchers from Kl Research Institute and Maccabi Healthcare Services (MCS) in Israel sourced data for the study from MCS, which is the second largest health organization in the country. Individuals (n=299,870) who tested positive for SARS-CoV-2 between March 2020 and October 2021 and were not admitted to the hospital within 30 days of a positive COVID-19 test were included in this study. Risk for 70 long COVID-19 outcomes were assessed and compared with a group of matched uninfected individuals (n=299,870). Early-phase sequelae was defined as 30-180 days after a positive test and late-phase sequelae as 180-360 days after a positive test.
The COVID-19 and control cohorts comprised individuals of median aged, 25 (interquartile range [IQR], 12-43) years, 50.6% were women, and 76.4% were unvaccinated. The cohort with COVID-19 had a higher proportion of individuals who were Jewish Orthodox and had low socioeconomic status.
Researchers noted the top 3 most common and the top 3 least common sequelae symptoms among the study population.
|Most Common Sequelae Symptoms||Anosmia and dysgeusia Respiratory disorders Concentration and memory conditions|
|Least Common Sequelae Symptoms||Diarrhea Lymphadenopathy Rhinorrhea|
They also found the 3 most common and the 3 least common chronic conditions.
|Most Common Chronic Conditions||Pericarditis Fatty liver Hypertension|
|Least Common Chronic Conditions||Congestive heart failure Celiac disease Chronic kidney disease|
Stratified by early and late period conditions, respiratory disorders (risk difference [RD], 3.7), hair loss (RD, 31.6), chest pain (RD, 56.3), myalgia (RD, 17.5), and cough (RD, 22.2) were at greater risk in the early period than the later period. Risk for arthralgia was increased in the late period (RD, 7.3).
Stratified by age, the most common conditions per group were:
- Dyspnea for those aged 0-4 years,
- Streptococcal tonsillitis for 5-11-year-olds,
- Anosmia and dysgeusia for 12-18- or 19-40-year-olds,
- Respiratory disorders for 41-60-year-olds, and
- Hair loss for those aged >60 years.
Of note, the highest number of long COVID-19 complaints were observed among the cohort of individuals aged 41-60 years.
Stratified by gender, patterns were generally similar between men and women, however, more women had hair loss in the early period (hazard ratio [HR], 2.09) compared with men (HR, 0.97).
Among the subset of individuals who were vaccinated, a lower risk for dyspnea was observed (HR, 1.58) compared with the unvaccinated individuals. All other outcomes were similar on the basis of vaccination status.
The results of this study may have been limited by the reliance on medical coding. Data on outcomes were not available.
“This nationwide dataset of patients with mild covid-19 suggests that mild disease does not lead to serious or chronic long-term morbidity in the vast majority of patients and adds a small continuous burden on healthcare providers,” the researchers noted. “Importantly, the risk for lingering dyspnoea was reduced in vaccinated patients with breakthrough infection compared with unvaccinated people, while risks of all other outcomes were comparable,” they concluded.
Mizrahi B, Sudry T, Flaks-Manov N, et al. Long covid outcomes at one year after mild SARS-CoV-2 infection: nationwide cohort study. BMJ. Published online January 11, 2023. doi:10.1136/bmj-2022-072529