Affiliations 

  • 1 Institute for Public Health, National Institutes of Health, Ministry of Health Malaysia Setia Alam Selangor Malaysia
  • 2 Department of Community Medicine, School of Medical Sciences Universiti Sains Malaysia Kubang Kerian Kelantan Malaysia
  • 3 Institute for Medical Research, National Institutes of Health Ministry of Health Malaysia Setia Alam Selangor Malaysia
Influenza Other Respir Viruses, 2023 Oct;17(10):e13193.
PMID: 37789877 DOI: 10.1111/irv.13193

Abstract

BACKGROUND: From the beginning of the COVID-19 pandemic until mid-October 2020, Malaysia recorded ~15,000 confirmed cases. But there could be undiagnosed cases due mainly to asymptomatic infections. Seroprevalence studies can better quantify underlying infection from SARS-CoV-2 by identifying humoral antibodies against the virus. This study was the first to determine the prevalence of SARS-CoV-2 infection in  Malaysia's general population, as well as the proportion of asymptomatic and undiagnosed infections.

METHODS: This cross-sectional seroprevalence study with a two-stage stratified random cluster sampling design included 5,131 representative community dwellers in Malaysia aged ≥1 year. Data collection lasted from 7 August to 11 October 2020 involving venous blood sampling and interviews for history of COVID-19 symptoms and diagnosis. Previous SARS-CoV-2 infection was defined as screened positive using the Wantai SARS-CoV-2 Total Antibody enzyme-linked immunosorbent assay and confirmed positive using the GenScript SARS-CoV-2 surrogate Virus Neutralization Test. We performed a complex sampling design analysis, calculating sample weights considering probabilities of selection, non-response rate and post-stratification weight.

RESULTS: The overall weighted prevalence of SARS-CoV-2 infection was 0.49% (95%CI 0.28-0.85) (N = 150,857). Among the estimated population with past infection, around 84.1% (95%CI 58.84-95.12) (N = 126 826) were asymptomatic, and 90.1% (95%CI 67.06-97.58) (N = 135 866) were undiagnosed.

CONCLUSIONS: Our study revealed a low pre-variant and pre-vaccination seroprevalence of SARS-CoV-2 infection in Malaysia up to mid-October 2020, with a considerable proportion of asymptomatic and undiagnosed cases. This led to subsequent adoption of SARS-CoV-2 antigen rapid test kits to increase case detection rate and to reduce time to results and infection control measures.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.