Learnings from the Australian first few X household transmission project for COVID-19

the Australian FFX Household Transmission Project Group

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Background: First Few “X” (FFX) studies provide a platform to collect the required epidemiological, clinical and virological data to help address emerging information needs about the COVID-19 pandemic. Methods: We adapted the WHO FFX protocol for COVID-19 to understand severity and household transmission dynamics in the early stages of the pandemic in Australia. Implementation strategies were developed for participating sites; all household members were followed for 14 days from case identification. Household contacts completed symptom diaries and had multiple respiratory swabs taken irrespective of symptoms. We modelled the spread of COVID-19 within households using a susceptible-exposed-infectious-recovered-type model, and calculated the household secondary attack rate and key epidemiological parameters. Findings: 96 households with 101 cases and 286 household contacts were recruited into the study between April–October 2020. Forty household contacts tested positive for SARS-CoV-2 in the study follow-up period. Our model estimated the household secondary attack rate to be 15% (95% CI 8–25%), which scaled up with increasing household size. Our findings suggest children were less infectious than their adult counterparts but were also more susceptible to infection. Interpretation: Our study provides important baseline data characterising the transmission of early SARS-CoV-2 strains from children and adults in Australia, against which properties of variants of concern can be benchmarked. We encountered many challenges with respect to logistics, ethics, governance and data management. Continued efforts to invest in preparedness research will help to test, refine and further develop Australian FFX study protocols in advance of future outbreaks. Funding: Australian Government Department of Health.

Original languageEnglish
Article number100573
JournalThe Lancet Regional Health - Western Pacific
Volume28
DOIs
Publication statusPublished or Issued - Nov 2022

Keywords

  • COVID-19
  • Epidemiology
  • Household transmission
  • Infectious disease
  • Public health
  • SARS-CoV-2

ASJC Scopus subject areas

  • Internal Medicine
  • Pediatrics, Perinatology, and Child Health
  • Health Policy
  • Obstetrics and Gynaecology
  • Public Health, Environmental and Occupational Health
  • Geriatrics and Gerontology
  • Psychiatry and Mental health
  • Infectious Diseases

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