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Covid-19 Primary Care Resources



When to suspect SARS-CoV-2 reinfection and how to investigate suspected cases

This information is sourced from PHE:

Reinfection refers to a new infection with SARS-CoV-2 following previous confirmed (PCR positive) infection and is distinct from persistent infection and relapse of infection. Reinfection with SARS-CoV-2 remains rare

Identification of reinfection is challenging:

  • there is currently no standard case definition for a SARS-CoV-2 reinfection
  • SARS-CoV-2 PCR positivity may persist for prolonged periods (frequently up to 90 days, sometimes beyond) following initial infection without necessarily indicating viable virus
  • PCR may also be intermittently negative
  • asymptomatic infection is common

Reinfection should be considered in the following circumstances:

  • a repeat positive PCR test 90 days or more after a previous positive PCR test
  • new Covid-19 symptoms in a patient with previous PCR positive infection after apparent full recovery (resolution of previous symptoms) AND a repeat positive PCR test (including within 90 days after a previous positive PCR test)

Clinical management of suspected SARS-CoV-2 reinfection in primary care:

  • Patients with suspected reinfection should be managed as if they are infectious
  • Inform the individual that a Covid-19 illness due to reinfection may not necessarily follow the same clinical course as the last time they had the infection; the illness could range from asymptomatic to severe
  • Take a full history including any underlying immunosuppression, recent overseas travel history and vaccination status
  • Consider testing with a full respiratory viral panel profile, in addition to taking bacterial respiratory samples, an atypical pneumonia screen, and other serology tests as appropriate (consider seeking advice from infection specialist)
  • Consider whether a repeat PCR rest is needed. Was the test taken via a pillar 1 PHE/NHS Laboratory?
  • If after initial assessment you still suspect an individual has SARS-CoV-2 reinfection contact your local infection service
  • Further investigation should be informed by an infection specialist, these will include antibody tests against both the spike and N protein
  • Specify reinfection when you notify public health

The following factors make reinfection much less likely:

  • if the second PCR test is within 90 days from the initial infection and the individual is asymptomatic, it is more likely to be a persistent positive result
  • persistent rather than new symptoms (aside from fever) since previous positive test