ABSTRACT
@#Objective: At the time of this study, the prevention of novel coronavirus disease 2019 (COVID-19) relied solely on nonpharmaceutical interventions. Implementation of these interventions is not always optimal and, consequently, several cases were imported into non-epidemic areas and led to large community outbreaks. This report describes the characteristics of the first community outbreak of COVID-19 in Viet Nam and the intensive preventive measures taken in response. Methods: Cases were detected and tested for SARS-CoV-2 by real-time reverse transcriptase polymerase chain reaction. Contact tracing and active surveillance were conducted to identify suspected cases and individuals at risk. Clinical symptoms were recorded using a standardized questionnaire. Results: In Vinh Phuc province from 20 January to 3 March 2020, there were 11 confirmed cases among 158 suspected cases and 663 contacts. Nine of the confirmed cases (81.8%) had mild symptoms at the time of detection and two (18.2%) were asymptomatic; none required admission to an intensive care unit. Five prevention and control measures were implemented, including quarantining a community of 10 645 individuals for 20 days. The outbreak was successfully contained as of 13 February 2020. Discussion: In the absence of specific interventions, the intensive use of combined preventive measures can mitigate the spread of COVID-19. The lessons learned may be useful for other communities.
ABSTRACT
BackgroundOne hundred days after SARS-CoV-2 was first reported in Vietnam on January 23rd, 270 cases have been confirmed, with no deaths. We describe the control measures used by the Government and their relationship with imported and domestically-acquired case numbers, with the aim of identifying the measures associated with successful SARS-CoV-2 control. MethodsClinical and demographic data on the first 270 SARS-CoV-2 infected cases and the timing and nature of Government control measures, including numbers of tests and quarantined individuals, were captured by Vietnams National Steering Committee for COVID-19 response. Apple and Google mobility data provided proxies for population movement. Serial intervals were calculated from 33 infector-infectee pairs and used to estimate the proportion of pre-symptomatic transmission events and time-varying reproduction numbers. FindingsAfter the first confirmed case on January 23rd, the Vietnamese Government initiated mass communications measures, case-contact tracing, mandatory 14-day quarantine, school and university closures, and progressive flight restrictions. A national lockdown was implemented between April 1st and 22nd. Around 200 000 people were quarantined and 266 122 RT-PCR tests conducted. Population mobility decreased progressively before lockdown. 60% (163/270) of cases were imported; 43% (89/208) of resolved infections remained asymptomatic for the duration of infection. 21 developed severe disease, with no deaths. The serial interval was 3.24 days, and 27.5% (95% confidence interval, 15.7%-40.0%) of transmissions occurred pre-symptomatically. Limited transmission amounted to a maximum reproduction number of 1.15 (95% confidence interval, 0.37-2.36). No community transmission has been detected since April 15th. InterpretationVietnam has controlled SARS-CoV-2 spread through the early introduction of mass communication, meticulous contact-tracing with strict quarantine, and international travel restrictions. The value of these interventions is supported by the high proportion of asymptomatic and imported cases, and evidence for substantial pre-symptomatic transmission. FundingThe Vietnam Ministry of Health and Wellcome Trust, UK. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSVietnam was one of the first countries outside of China to detect imported and human-to-human transmitted SARS-CoV-2 within its borders. Yet, as of May 1st, a total of only 270 cases have been confirmed, no deaths have occurred, and no community transmission has been detected since April 15th despite intensive screening, tracing and testing. We did a PubMed database search to identify studies investigating COVID-19 response in Vietnam using the terms "Vietnam", "COVID-19", and "SARS-CoV-2". All relevant articles were evaluated. Studies describe cases of COVID-19 and their management, aspects of the government response from newspapers and online government sources, but there are no previous reports using national data to describe and investigate the national epidemic and the impact of control measures cases over time. Added value of this studyWe used data from the National Steering Committee for COVID-19 response to give a comprehensive account of the first 100 days of the SARS-CoV-2 epidemic in Vietnam, including case numbers and their symptomatology, the estimated reproductive number by week, and their relation to the multiple control measures instituted by the Vietnam Government over time. We show two distinctive features of Vietnams response. First, the Government took rapid actions to restrict international flights, closed schools and universities, and instituted meticulous case-contact tracing and quarantining from late January, well before these measures were advised by WHO. Second, they placed mass communication, education, and the identification, serial testing, and 14-day quarantine of all direct contacts of cases, regardless of symptom development, at the heart of the response. The value of strict contact-tracing and quarantine is supported by the high proportion of asymptomatic cases (43%) and imported cases (60%), and evidence for substantial pre-symptomatic transmission. Implications of all the available evidenceVietnam has had remarkable success in controlling the emergence of SARS-CoV-2. Our report provides a complete picture of the control of SARS-CoV-2 in Vietnam, with lessons for other Governments seeking to extend national SARS-CoV-2 control or prevent future epidemics. Our findings shows the importance of acting early, before the virus becomes established in the community, and before the case numbers overwhelm systems of case-contact tracing and mass quarantine. They also demonstrate the value of effective mass communication in rapidly educating the public in infection prevention measures and providing real-time information on the state of the epidemic.
