A new study published in the journal Clinical Infectious Diseases has found that the coronavirus strain that is spreading globally – COVID-19 – can be detected in patients’ saliva. If saliva can in fact be used to diagnose COVID-19, this approach could be valuable not only for patients but also for emergency physicians, hospital physicians, and other healthcare professionals. Indeed, the noninvasive nature of saliva collection can circumvent exposure and infection risks associated with other means of diagnosis, such as techniques involving nasopharyngeal and oropharyngeal swabs.

In December, COVID-19, a severe acute respiratory syndrome coronavirus (SARS-CoV), emerged in China and after a rapid spread throughout China, has made its way to every continent other than Antarctica. Initial study of the virus has shown that it is closely related to bat SARS-like coronaviruses. However, COVID-19 is associated with spikes in specific proteins that distinguish it from other SARS-like viruses.

Given how efficiently COVID-19 can transfer between humans, experts have warned that fast identification of the virus is critical to controlling its spread. However, rapid identification must also be balanced with protecting healthcare workers. In this spirit, this new study aimed to determine the feasibility of using patient saliva to diagnose the virus.

To investigate the detectability of the virus in saliva, researchers investigated saliva from 12 patients with the virus – 5 women and 7 men. They found that they could identify the virus in the saliva of 11 of these 12 patients, and the viral content was higher in those from whom the samples were taken earlier on after their initial diagnosis.

The patients were all located in Hong Kong and ranged in age from 37 to 75 years old.  Their saliva was collected between 0 and 7 days after they were hospitalized for the coronavirus. Patients coughed saliva into a container that had 2 milliliters of a viral transport medium added to it. The researchers then conducted cultures of the viral samples and examined the cytopathic activity for up to 7 days.

While more work is needed to determine if and precisely how saliva may be used as a diagnostic specimen for COVID-19, these initial data suggest that saliva may provide a beneficial noninvasive specimen type to help with the monitoring of viral load related to COVID-19.

Reference

Kai-Wang, K. et al. (2020). Consistent detection of 2019 novel coronavirus in saliva. Clinical Infectious Diseases. https://doi.org/10.1093/cid/ciaa149