text: Assessment of the Frequency and Variety of Persistent Symptoms Among Patients With COVID 19 A Systematic Review Infection with COVID 19 has been associated with long term symptoms but the frequency variety and severity of these complications are not well understood Many published commentaries have proposed plans for pandemic control that are primarily based on mortality rates among older individuals without considering long term morbidity among individuals of all ages Reliable estimates of such morbidity are important for patient care prognosis and development of public health policy To conduct a systematic review of studies examining the frequency and variety of persistent symptoms after COVID 19 infection A search of PubMed and Web of Science was conducted to identify studies published from January 1 2020 to March 11 2021 that examined persistent symptoms after COVID 19 infection Persistent symptoms were defined as those persisting for at least 60 days after diagnosis symptom onset or hospitalization or at least 30 days after recovery from the acute illness or hospital discharge Search terms included COVID 19 SARS CoV 2 coronavirus 2019 nCoV long term after recovery long haul persistent outcome symptom follow up and longitudinal All English language articles that presented primary data from cohort studies that reported the prevalence of persistent symptoms among individuals with SARS CoV 2 infection and that had clearly defined and sufficient follow up were included Case reports case series and studies that described symptoms only at the time of infection and or hospitalization were excluded A structured framework was applied to appraise study quality A total of 1974 records were identified of those 1247 article titles and abstracts were screened After removal of duplicates and exclusions 92 full text articles were assessed for eligibility 47 studies were deemed eligible and 45 studies reporting 84 clinical signs or symptoms were included in the systematic review Of 9751 total participants 5266 54 0 were male 30 of 45 studies reported mean or median ages younger than 60 years Among 16 studies most of which comprised participants who were previously hospitalized the median proportion of individuals experiencing at least 1 persistent symptom was 72 5 interquartile range IQR 55 0 80 0 Individual symptoms occurring most frequently included shortness of breath or dyspnea 26 studies median frequency 36 0 IQR 27 6 50 0 fatigue or exhaustion 25 studies median frequency 40 0 IQR 31 0 57 0 and sleep disorders or insomnia 8 studies median 29 4 IQR 24 4 33 0 There were wide variations in the design and quality of the studies which had implications for interpretation and often limited direct comparability and combinability Major design differences included patient populations definitions of time zero ie the beginning of the follow up interval follow up lengths and outcome definitions including definitions of illness severity This systematic review found that COVID 19 symptoms commonly persisted beyond the acute phase of infection with implications for health associated functioning and quality of life Current studies of symptom persistence are highly heterogeneous and future studies need longer follow up improved quality and more standardized designs to reliably quantify risks 