Factors Associated with Asymptomatic COVID-19 Patients in Petaling District, Selangor, Malaysia

Introduction: The rapid spread of the COVID-19 worldwide has led the World Health Organization (WHO) to declare COVID-19 outbreak as a pandemic on March 11, 2020. This study aims to determine the factors associated with asymptomatic COVID-19 patients in Petaling District, Selangor, Malaysia. Methods: Data on COVID-19 patients were extracted from the database of confirmed cases in Petaling District Health Office, Selangor, Malaysia from 3rd February 2020 to 30th April 2020. An asymptomatic laboratory-confirmed case is a person infected with COVID-19 who does not develop any symptoms. The study included socio-demographic variables, the detailed information on clinical manifestations and co-morbidity of the patients. Descriptive and multivariable logistic regression analyses were conducted to determine the factors associated with asymptomatic patients. Results: The overall COVID-19 patients in Petaling District were 434. Approximately 70% (N = 292) of the patients were symptomatic while 32.7% (N = 142) were asymptomatic. Multivariable logistic regression analyses revealed that factors significantly associated with asymptomatic patients were age below 40 years old (aOR: 1.79, 95% CI 1.11, 2.86), non-Malaysians (aOR: 3.22, 95% CI 1.44, 7.19) and local cases (aOR: 2.51, 95% CI 1.42, 4.42). Gender, ethnicity, co-morbidity and township were not significantly associated with asymptomatic patients. Conclusion: Approximately one-third of COVID-19 patients were asymptomatic and the risk factors identified were younger age, non-Malaysians and local cases. Rigorous epidemiological investigation and laboratory examinations are helpful in identifying COVID-19 cases among these group of people who are asymptomatic.  Keywords: COVID-19 - asymptomatic - pandemic - Malaysia