COVID-19 health care worker testing

Introduction

whilst all HCWs in Australia will be required to be vaccinated for Covid-19, as the vaccination is imperfect (protection against transmissable Covid-19 infections is 60-80% depending upon age and time since vaccinated), HCW's are at risk of infection, especially if working in high viral loads, failure of Tier 3 PPE compliance, or cross-infection from other HCWs in tea rooms, not to mention community acquisition.
fortunately severe illness or death is very unlikely for HCW's who are fully vaccinated (especially if well and aged under 50yrs), nevertheless, an active surveillance programme is warranted during periods of high community prevalance of Covid-19 to reduce exposure risks to other HCWs, their families and patients
the regime for such surveillance needs to be assessed for:
- accuracy and timeliness of detecting infection
- cost of regime in terms of:
  - HCW inconvenience and time
  - laboratory processing impacts

lower sensitivity tests (eg saliva PCR or rapid antigen swab tests) every 1-3 days
easy saliva tests less intrusive for HCWs
may not detect low viral loads that are likely to be seen in vaccinated asymptomatic persons and any positives are just as likely to be false positives as true positives for RATs when pretest probability is very low

weekly PCR swab tests
more likely to detect infection than saliva PCR or RAT especially early in infection or later once viral loads fall
lower resource drain on HCW and system but may result in detection delays with potential for large numbers to be exposed although this is partly mitigated by PPE and low viral loads of a vaccinated asymptomatic person