Characterisation of SARS-CoV-2 in saliva of healthcare workers in high-risk settings

Funder: OUCRU (Wellcome funding)

Principal Investigator: Maia Rabaa

Location of activity: Vietnam


  1. To define the frequency and characteristics of asymptomatic carriage of SARS-CoV-2 in health care workers caring for COVID-19 patients.
  2. To define the frequency of COVID-19 occurring in health care workers caring for COVID-19 patients.
  3. To define the duration of detectable SARS-CoV-2 in health care workers prior to developing symptoms.
  4. To determine whether transmission of SARS-CoV-2 occurs from health care workers (asymptomatic and prodromal) to community contacts.
  5. To demonstrate the utility of filter paper collection of saliva as a surveillance tool for SARS-CoV-2 infection.
  6. To investigate the molecular epidemiology, intrahost diversity and evolution of SARS-CoV-2 in asymptomatic and symptomatic SARS-CoV-2 infections in health care workers.


Understanding the risk of carriage and transmission to and by health care workers will enable the design of interventions to reduce this risk. Development of a robust cold chain-independent sampling modality will enable enhanced population surveillance, diagnosis and follow-up.

Primary Objectives

  • Early identification and understanding of the incidence of symptomatic and asymptomatic infection in health care workers.
  • Assessment of the risk of transmission to the community by asymptomatic health care workers.
  • Assessment of filter paper-based saliva sample collection for the diagnosis and sequence characterisation of SARS-CoV-2.
  • Sequence & epidemiological analysis of transmission from infected patients to HCWs (coupling with data collected under other studies).

Outputs to date