AIMS AND OBJECTIVES: To estimate the prevalence and associated factors of COVID-19 in people with flu-like syndrome in Ceara, Brazil. BACKGROUND: COVID-19 is an infectious disease that has led to a worldwide public health emergency. More than 30,000 cases were confirmed in Brazil, especially in the States of Sao Paulo, Rio de Janeiro and Ceara. The capital of the Ceara State is the one with the highest incidence of COVID-19 in Brazil. Estimating the prevalence of the disease and its associated factors is important to offer adequate health care. DESIGN: A cross-sectional study with secondary data of people notified with flu-like syndrome and COVID-19 test results. METHODS: 19,967 cases of flu-like syndrome were analysed according to the result of the COVID-19 test. Predictive variables were as follows: age range, sex, women in puerperium, presence or absence of cardiovascular diseases, diabetes, haematological illness, immunodeficiencies, neurological diseases, obesity, renal diseases and Down syndrome. Robust Poisson regression models estimated the prevalence ratios of COVID-19. The research was reported via STROBE guidelines for cross-sectional studies. RESULTS: The prevalence of COVID-19 in the population was 10.37%. In the final model, the following variables were associated with COVID-19: aged people, male sex, cardiovascular diseases and diabetes. CONCLUSION: Among the flu-like syndrome cases, COVID-19 prevalence was high. In the Ceara State, clinical factors such as aged people, male sex, cardiovascular diseases and diabetes can enhance the prevalence of COVID-19 by up to 2.57 times. RELEVANCE TO CLINICAL PRACTICE: The identification of factors that are associated with the enhanced prevalence of COVID-19 facilitates early diagnosis, and adequate and prompt treatment. This knowledge may avoid an unfavourable prognosis of the disease.