COVID-19 has evolved into a serious clinical condition, especially in patients with comorbidities. However, the literature has diverged in relation to the main characteristics of patients prone to severe evolution. Objective: This study aimed to understand different variables that may be associated with the clinical management of COVID-19 for a better clinical response and prognosis. Methods: This is a systematic review in which the search in PubMed, Cochrane, EMBASE and LILACS databases. A manual and gray literature search on Google Scholar was also conducted. There was no country or region restriction and only studies in Portuguese, English and Spanish were included. Results: Of the 21 studies included in Primary Health Care (PHC) for eligibility, five studies from five countries involving 27,754 patients were analysed and, of the four eligible studies, one study was included for secondary care. Overall, the mean age of the COVID-19 population in PHC was around 41 years old, the number of cases was higher for females and, there was no difference between the groups without and with exposure, sex (ρ=0.322) and age (ρ=0.395). More than half of the patients had symptoms and, 47% had comorbidities. Heart diseases were the most prevalent among them. Approximately 79% of those infected had non-essential occupation. There was evidence that non-essential occupation was associated with infected individuals (ρ=0.002). Conclusions: This review identified that there may be greater vulnerability to contamination and aggravation of COVID-19 in female individuals, with adult age in non-essential activity, presence of chronic non-communicable diseases.