Dr David Rutherford (pictured) and Dr David Smith explain what GPs need to know about COVID testing.
It has been a long 18 months living with COVID-19, despite being in a luckier State than most. Changes to general practice have been enormous, including pivoting to telehealth and keeping up with ever-changing guidelines for testing and vaccination.
It is timely to clarify the role of testing in WA.
Since vaccination started in February, the number of serology results have steadily increased. Some of these are for overseas travel when required for certain country entry requirements (mostly China), but increasingly they appear to be done to check immune response to vaccination.
The laboratories must contact the Public Health Emergency Operations Centre, which is notified of any positive COVID tests, either through PCR, rapid antigen testing or serology.
In most cases there is little clinical benefit to checking serology, with the exceptions of exposure to COVID-19 in the past for someone who was not tested at the time. This will alter management.
As we know from the data, all the current vaccines have high effectiveness but are known to be particularly effective at preventing severe illness and reducing the need for hospital/ICU admission.
While serology can show a positive response to either infection or vaccination, it does not indicate whether there is any residual protection from either source.
If there is any concern that vaccination coverage may be weakening in an individual, then it is best to recommend booster vaccination, rather than checking serology. This can be done for immune-compromised patients two months after their last dose or after six months for immune-competent patients. Currently there is no clinical indication for more than three doses.
Serology has no place for testing in suspected acute COVID-19.
Nose and throat PCR remains the test of choice for suspected acute COVID-19. PCR is organised through many laboratories and hospitals in WA.
When people are symptomatic, it is most important to look out for higher risk patients including health care workers, Uber and taxi drivers, port workers, security guards, flight crew, truck drivers, those working or living in residential facilities, prisons and abattoirs, and interstate travellers or their close contacts.
The interstate border restrictions change regularly based on risk, so it is good to keep abreast of this through the WA Health Department website.
In the future, once vaccination rates reach a certain level and borders reopen, more people will be in home quarantine. It is important to maintain high vigilance and to test using PCR when symptoms are present.
If someone has flu-like symptoms, ideally telehealth should be used first, or a negative COVID test returned, before seeing face-to-face, as per RACGP guidelines. Rapid antigen testing is currently not available in the community in WA.
Finally, vaccination remains the best protection for individuals and the community as a whole.
ED: Dr Rutherford has continued his work in GP/travel medicine while working at PHEOC, and Dr Smith is a clinical microbiologist at Pathwest.