Descriptive epidemiology of the first wave of COVID-19 in Petaling District, Malaysia: Focus on asymptomatic transmission

BACKGROUND

COVID-19 was first detected in Malaysia on 25 January 2020. Multiple clusters were detected in Petaling District, with the first locally transmitted case reported on 8 February. Descriptive analyses of the epidemiology of the COVID-19 outbreak in Petaling are presented, from the first case to the end of the first wave.

METHODS

All laboratory-confirmed COVID-19 cases reported to the Petaling District Health Office between 1 February and 26 June 2020 were analysed. Socio-demographic characteristics, symptoms, date of onset, date of exposure, travel history and history of comorbidities were obtained by phone interviews using one of two investigation forms. The descriptive analysis was conducted according to time, place and person.

RESULTS

There were 437 COVID-19 cases, for an incidence rate of 24/100 000 population. Ten (2.3%) deaths and 427 recovered cases were recorded. Of the 437 cases, 35.5% remained asymptomatic and 64.5% were symptomatic. Common symptoms included fever (43.8%), cough (31.6%) and sore throat (16.2%); 67.3% had no comorbidities, 62.5% reported close contact with a confirmed case, and 76.7% were local infections. Transmission occurred in four main groups: religious gatherings (20.4%), corporations (15.1%), health facilities (10.3%) and a wholesale wet market (6.4%). In 31.9% of confirmed cases, an epidemiological link to an asymptomatic case was found.

CONCLUSION

Transmission of the disease by asymptomatic cases should be emphasized to ensure continuous wearing of face masks, hand hygiene and social distancing. Further research should be conducted to better understand the transmission of SARS-CoV-2 from asymptomatic cases.

First Local Transmission Cluster of COVID-19 in Malaysia: Public Health Response

Introduction: Rapid public health response is important in controlling the transmission of coronavirus disease 2019 (COVID-19). In this study, we described the public health response taken by the Ministry of Health of Malaysia in managing the first local transmission cluster of COVID-19 related to mass-gathering and inter-state traveling to celebrate a festival. Methods: We summarized strategies implemented by the Malaysia Crisis Preparedness and Response Centre (CPRC) in managing the first local transmission of COVID-19. We collected information related to the epidemiological investigation of this cluster and described the inter-state network in managing the outbreak. Results: This first local transmission of COVID-19 in Malaysia had a history of contact with her older brother, the index case, who was the first Malaysian imported case. Only two positive cases were detected out of 59 contacts traced from the index case. Close contacts with infected person/s, inter-state movement, and public/family gatherings were identified as the sources of transmission. A large number of contacts were traced from inter-state traveling, and family gatherings during the festive season, and health consultations and treatment. Conclusion: Close contacts from inter-state movement and public/family gatherings were identified as the source of transmission. Family or public gatherings during festivals or religious events should be prohibited or controlled in COVID-19 prevalent areas. A structured surveillance system with rapid contact tracing is significant in controlling the transmission of COVID-19 in the community.