This article was included in a NSW Health newsletter and was . For the latest information about COVID-19 in NSW, please visit NSW Government - COVID-19.

Since December last year, scores of facility workers have been turning up to work at Sydney quarantine hotels open-mouthed. Not out of wonder or amazement, but because they have been getting daily saliva tests under NSW Health's COVID-19 saliva surveillance program.

Bolstering our defences against the COVID-19 virus, especially the new highly infectious strains that have emerged internationally, saliva testing acts as an early warning screening test for those working in quarantine hotels.

First and foremost, the saliva test is not an alternative to the nose and throat COVID-19 PCR test, which is still the most accurate diagnostic test for anyone who is suspected of having COVID-19. Although the laboratory testing process is the same, a saliva sample is only about 85 per cent as accurate as a nose and throat swab.

The benefit of saliva testing lies in the ease of collection. It is quick, painless and able to be self-collected by the person, which means samples can be easily collected on a daily basis. This is why saliva testing has been incorporated into NSW Health's testing regime as a valuable screening test for asymptomatic staff (those without symptoms) working at our hotel quarantine sites.

As a screening test, anyone whose saliva test indicates the presence of COVID-19 must immediately self-isolate and undergo diagnostic testing using the usual nose and throat swab test.

NSW Health Pathology is supporting NSW Health's implementation of a new COVID-19 saliva surveillance program.

NSW Health Pathology Pre-Analytical Lead Judy Kempton-Webb, said the process of establishing and launching the saliva testing program was a team effort.

'The need for the program was identified by the Ministry of Health and made possible by NSW Health Pathology, Sydney Local Health District (SLHD) and Elizabeth Macarthur Agricultural Institute (EMAI). In just a short time, collection kits were sourced, collection procedures established, and laboratory testing began,' Ms Kempton-Webb said.

Like many other laboratory consumables, COVID-19 swabs and viral transport media have been in short supply nationally and globally. NSW Health Pathology is working with a local manufacturer who produces the saliva swabs and another who produces the viral transport media. This collaboration has secured an ongoing and reliable supply to meet the demand of occupational surveillance testing for NSW.

'The saliva specimen is collected by the person themselves using a swab that looks like a small honey dipper,' Ms Kempton-Webb said.

'The honey dipper swab, produced using innovative 3D printing technology, has been designed to collect a certain amount of the person's saliva when they place the plastic sterile swab device on their tongue for 30 seconds.

'There are small grooves in the swab that make it look like a honey dipper, and these collect the amount of saliva required for the test.'

As more and more people started to return to Australia from overseas, we began seeing increased numbers of cases in quarantine facilities. The need for additional safety measures to help protect hotel quarantine workers and the community from transmission became critical.

NSW Health Pathology Microbiologist and Public Health Pathology Acting Director Dr Catherine Pitman, said the COVID-19 saliva surveillance program has been scaled up progressively.

'We began with saliva testing in a single laboratory last December and in January, a second laboratory commenced testing. Now the two labs - Royal Prince Alfred laboratory and the EMAI - are sharing the testing of approximately 2,500 samples per day,' Dr Pitman said.

'While these tests are being processed by staff in our Royal Prince Alfred laboratory and EMAI, we're working to expand this testing to other labs, as required. Any extra demand on the labs processing these tests has been managed by redistributing the diagnostic tests to other labs.

'That's one of the key benefits of NSW Health Pathology being a state-wide system, in that we can manage surge capacity across a network of laboratories.'

To date, more than 50,000 tests have been undertaken, with daily saliva screening now conducted on staff at 21 hotels across Sydney. The saliva screening test is not available to the wider community, as the regular nose and throat swab is the most accurate diagnostic test and the test of choice for anyone with suspected COVID-19 or contact with a positive COVID-19 case.

So, while the 'nasal and throat swab' is still the preferred specimen for detecting the virus and remains the gold standard for diagnosing COVID-19, there is certainly a specific place for the saliva screening test, adding yet another layer to NSW Health's defences against this coronavirus pandemic.

Current as at: Thursday 4 February 2021
Contact page owner: Health Protection NSW