The Second Wave of COVID-19 in South and Southeast Asia and the Effects of Vaccination

Haitao Song, Guihong Fan, Yuan Liu, Xueying Wang, Daihai He

Research output: Journal article publicationJournal articleAcademic researchpeer-review

23 Citations (Scopus)


Background: By February 2021, the overall impact of coronavirus disease 2019 (COVID-19) in South and Southeast Asia was relatively mild. Surprisingly, in early April 2021, the second wave significantly impacted the population and garnered widespread international attention. Methods: This study focused on the nine countries with the highest cumulative deaths from the disease as of August 17, 2021. We look at COVID-19 transmission dynamics in South and Southeast Asia using the reported death data, which fits a mathematical model with a time-varying transmission rate. Results: We estimated the transmission rate, infection fatality rate (IFR), infection attack rate (IAR), and the effects of vaccination in the nine countries in South and Southeast Asia. Our study suggested that the IAR is still low in most countries, and increased vaccination is required to prevent future waves. Conclusion: Implementing non-pharmacological interventions (NPIs) could have helped South and Southeast Asia keep COVID-19 under control in 2020, as demonstrated in our estimated low-transmission rate. We believe that the emergence of the new Delta variant, social unrest, and migrant workers could have triggered the second wave of COVID-19.

Original languageEnglish
Article number773110
Pages (from-to)1-7
Number of pages7
JournalFrontiers in Medicine
Publication statusPublished - 14 Dec 2021


  • COVID-19
  • Delta variants
  • infection attack rate
  • infection fatality rate
  • mathematical modeling
  • South Asia
  • Southeast Asia
  • vaccination

ASJC Scopus subject areas

  • General Medicine


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