Saliva testing for SARS-CoV-2 takes off
LEIPZIG, Germany: Researchers in India have found that scientific literature supports salivary diagnostics for SARS-CoV-2 infection as an alternative to sampling techniques that involve throat and nasopharyngeal swabs (NPSs). Salivary diagnostic testing has been trialled in numerous initiatives around the world—including recently at Auckland Airport in New Zealand—and healthcare workers at government hospitals in Malaysia will soon begin testing for SARS-CoV-2 using saliva samples.
In January, researchers from Jamia Millia Islamia and the All India Institute of Medical Sciences—both located in New Delhi in India—undertook a scoping review that aimed to explore the evidence on salivary diagnostics for SARS-CoV-2 infection as an alternative to the widely used NPS sampling. The researchers reviewed the literature with the aim of studying the effective value of salivary diagnostics in the detection of SARS-CoV-2 and providing research suggestions.
In discussing the findings of the review, which was published on 26 January in BDJ Open, the researchers noted that throat swabs and NPSs can be dangerous for healthcare workers because the sampling techniques are invasive and can induce sneezing and further expelling of virus particles. They also noted that throat swabs and NPSs must be carried out by trained healthcare professionals, are time-consuming and require the use of consumables that are in high demand. “Further, as the pandemic magnifies in intensity, the requirement of mass screening in densely populated locations, more so in poor and developing countries, is rising,” the researchers wrote. They said that a huge demand for swabs was expected in the near future and that alternative testing methods that are reliable, provide ease of use and are less technique-sensitive are urgently needed.
The researchers concluded that they supported the hypothesis that saliva is a viable sample collection technique for the detection of the virus. “Sufficient evidence has been generated in the present scoping review related to salivary specimens in SARS-CoV-2 for viral replication, longevity, sensitivity, specificity with other related viruses, and its practicality in the collection of specimens,” the researchers wrote.
Saliva testing for SARS-CoV-2 begins in New Zealand
Since the pandemic began, research such as that described here has encouraged organisations and health authorities to trial and implement saliva-based testing. Last year, Dental Tribune International reported on a number of such initiatives, including salivary diagnostic testing that was undertaken in a partnership between the Yale School of Public Health and the National Basketball Association in the US.
New Zealand’s largest airport has begun testing airport staff for SARS-CoV-2 infection using saliva-based testing—in addition to mandatory testing using NPSs. New Zealand closed its borders in March 2020, and the country’s airports and government-run quarantine facilities for international arrivals have since become a buffer zone between civil life in the island nation and the rest of the world.
The SHIELD rapid saliva-based test being used does not need to be conducted by healthcare professionals, and health authorities hope that it will help them to identify asymptomatic cases of COVID-19, news site Stuff reported in mid-February. The test is based on reverse transcriptase-polymerase chain reaction (RT-PCR) tests, and its use has been approved in New Zealand.
Malaysia poised to roll out saliva-based testing at hospitals
Government-run hospitals in Malaysia will soon begin using deep throat salivary diagnostic tests in their battle against COVID-19. According to Malay Mail, Health Minister Datuk Seri Dr Adham Baba says that the sensitivity of the sampling method is 96.67% and that it can be used for RT-PCR tests.
Speaking to reporters, Adham said: “The health ministry has received approval in principle from [the Institute for Medical Research] to use the saliva sampling method at government hospitals first.” He added that he expected that saliva testing will reduce the need for personal protective equipment because individuals could collect the saliva samples themselves.
“Patients will be asked to remove their own saliva into a specimen cup and the cup will then be sent to the laboratory for testing,” Adham was quoted as saying. He also told reporters that other countries that had used saliva samples for SARS-CoV-2 testing had proved it to be a cheaper and more consistent sampling method.