ABSTRACT
ObjectivesThe multifaceted manifestation of COVID-19 requires longitudinal characterization of symptoms, to aid with screening and disease management. MethodsPhone interviews and follow-ups were completed with 112 mostly mild COVID-19 RT-PCR-positive adult patients, over a six-months period. ResultsMore than one symptom at disease onset was experienced by [~]70% of the patients. About 40% of the patients experienced fever, dry cough, headache, or muscle ache as the first symptom. Fatigue, if reported, usually was the first to appear. Smell and taste changes were experienced 3.9 {+/-} 5.4 and 4.6 {+/-} 5.7 days (mean {+/-} SD) after disease onset and emerged as first symptom in 15% and 18% of patients, respectively. Fever had the shortest duration (5.8 {+/-} 8.6 days), and taste and smell changes were the longest-lasting symptoms (17.2 {+/-} 17.6 and 18.9 {+/-} 19.7 days, durations censored at 60 days). Longer smell recovery correlated with smell change severity. Cough, taste change and smell change persisted after negative RT-PCR tests (in 20%, 26% and 29% of the patients in total). At six-months follow-up, 46% of the patients had at least one unresolved symptom, most commonly fatigue (21%), chemosensory changes (14%) or breath difficulty (9%). ConclusionsMore than one symptom typically occurred at disease onset. Chemosensory changes and cough persisted after negative RT-PCR in a quarter of the patients. Almost half of the patients reported at least one unresolved symptom at six-months follow up, mainly fatigue, smell changes and breath difficulty. Our findings highlight the prevalence of long-lasting effects of COVID-19.
ABSTRACT
BackgroundClinical diagnosis of COVID-19 poses an enormous challenge to early detection and prevention of COVID-19, which is of crucial importance for pandemic containment. Cases of COVID-19 may be hard to distinguish clinically from other acute viral diseases, resulting in an overwhelming load of laboratory screening. Sudden onset of taste and smell loss emerge as hallmark of COVID-19. The optimal ways for including these symptoms in the screening of suspected COVID-19 patients should now be established. MethodsWe performed a case-control study on patients that were PCR-tested for COVID-19 (112 positive and 112 negative participants), recruited during the first wave (March 2020 - May 2020) of COVID-19 pandemic in Israel. Patients were interviewed by phone regarding their symptoms and medical history and were asked to rate their olfactory and gustatory ability before and during their illness on a 1-10 scale. Prevalence and degrees of symptoms were calculated, and odds ratios were estimated. Symptoms-based logistic-regression classifiers were constructed and evaluated on a hold-out set. ResultsChanges in smell and taste occurred in 68% (95% CI 60%-76%) and 72% (64%-80%), of positive patients, with 24 (11-53 range) and 12 (6-23) respective odds ratios. The ability to smell was decreased by 0.5{+/-}1.5 in negatives, and by 4.5{+/-}3.6 in positives, and to taste by 0.4{+/-}1.5 and 4.9{+/-}3.8, respectively (mean {+/-} SD). A penalized logistic regression classifier based on 5 symptoms (degree of smell change, muscle ache, lack of appetite, fever, and a negatively contributing sore throat), has 66% sensitivity, 97% specificity and an area under the ROC curve of 0.83 (AUC) on a hold-out set. A classifier based on degree of smell change only is almost as good, with 66% sensitivity, 97% specificity and 0.81 AUC. Under the assumption of 8% positives among those tested, the predictive positive value (PPV) of this classifier is 0.68 and negative predictive value (NPV) is 0.97. ConclusionsSelf-reported quantitative olfactory changes, either alone or combined with other symptoms, provide a specific and powerful tool for clinical diagnosis of COVID-19. The applicability of this tool for prioritizing COVID-19 laboratory testing is facilitated by a simple calculator presented here.
