Spatiotemporal distribution of COVID-19 during the first 7 months of the epidemic in Vietnam

Abstract

Background Understanding the spatiotemporal distribution of emerging infectious diseases is crucial for implementation of control measures. In the first 7 months from the occurrence of COVID-19 pandemic, Vietnam has documented comparatively few cases of COVID-19. Understanding the spatiotemporal distribution of these cases may contribute to development of global countermeasures. Methods We assessed the spatiotemporal distribution of COVID-19 from 23 January to 31 July 2020 in Vietnam. Data were collected from reports of the World Health Organization, the Vietnam Ministry of Health, and related websites. Temporal distribution was assessed via the transmission classification (local or quarantined cases). Geographical distribution was assessed via the number of cases in each province along with their timelines. The most likely disease clusters with elevated incidence were assessed via calculation of the relative risk (RR). Results Among 544 observed cases of COVID-19, the median age was 35 years, 54.8% were men, and 50.9% were diagnosed during quarantine. During the observation period, there were four phases: Phase 1, COVID-19 cases occurred sporadically in January and February 2020; Phase 2, an epidemic wave occurred from the 1st week of March to the middle of April (Wave 1); Phase 3, only quarantining cases were involved; and Phase 4, a second epidemic wave began on July 25th, 2020 (Wave 2). A spatial cluster in Phase 1 was detected in Vinh Phuc Province (RR, 38.052). In Phase 2, primary spatial clusters were identified in the areas of Hanoi and Ha Nam Province (RR, 6.357). In Phase 4, a spatial cluster was detected in Da Nang, a popular coastal tourist destination (RR, 70.401). Conclusions Spatial disease clustering of COVID-19 in Vietnam was associated with large cities, tourist destinations, people’s mobility, and the occurrence of nosocomial infections. Past experiences with outbreaks of emerging infectious diseases led to quick implementation of governmental countermeasures against COVID-19 and a general acceptance of these measures by the population. The behaviors of the population and the government, as well as the country’s age distribution, may have contributed to the low incidence and small number of severe COVID-19 cases.

Clinical characteristics and mortality risk among critically ill patients with COVID-19 owing to the B.1.617.2 (Delta) variant in Vietnam: A retrospective observational study

“…In Vietnam, the number of COVID-19 cases was relatively small, with no deaths, during the first 7 months of the pandemic. In contrast, over 4.3 million and 2.5 million cases, respectively, were reported in the United States and Brazil, with a case fatality rate of approximately 3.5% in both countries [2,3]. However, following an epidemic in summer 2021, the second year of the pandemic, the cumulative number of COVID-19 cases in Vietnam increased rapidly, reaching over 961,000 cases by the 1 st November, 2021, particularly owing to the emergence of the B.1.617.2 (Delta) variant of SARS-CoV-2 [4,5].…”

Investigating Linkages Between Spatiotemporal Patterns of the COVID-19 Delta Variant and Public Health Interventions in Southeast Asia: Prospective Space-Time Scan Statistical Analysis Method

“…Our results indicated that easing restrictions could lead to long-term existence of high-risk clusters and recurrent high risk in certain districts. Furthermore, previous studies on modeling linkages between NPIs and COVID-19 transmission were generally retrospective or predictive analyses and often focused on a single country [ 62 - 66 ]. The advantage of this study over prior works is that we provided a novel insight for timely and cross-nation surveillance of the dynamics and characteristics of the Delta variant at the district level in SEA.…”

Genomic epidemiology of SARS-CoV-2 in Cambodia, January 2020 to February 2021

“…Neighbouring countries, such as Laos, Thailand, and Vietnam, also had low incidences of COVID-19 cases due to the quick implementation of countermeasures and efficient screening and isolation of confirmed cases, similar to measures taken in Cambodia ( Issac et al. 2021 ; Manabe et al. 2021 ; Phonvisay et al.…”