The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Increased testing of COVID-19 is often considered a prerequisite to start 're-opening' the country. Currently, there are three leading test types for COVID-19.
- Reverse transcription-polymerase chain reaction (RT-PCR) tests. Samples are collected by swabbing the back of the patient's throat or nose using a long thin nasopharyngeal swab. Then the virus's ribonucleic acids (RNA) are copied millions to billions of times to amplify the signal and detect the virus.
- Antibody or serology tests. Antibody tests are performed on the patient's blood, which can be obtained from a finger prick or taken from a vein. Then a trained expert analyzes the blood for the presence of antibodies produced by the body to fight off SARS-CoV-2.
- Antigen tests. In an antigen test, the patient puts a sample, such as a throat swab, onto a special strip, the color of the strip changes if SARS-CoV-2 is present. An antigen is a foreign substance present in the body. These tests look for the corona spike proteins. Currently, these tests are less proven and unreliable and are not currently available to consumers.
Therefore, the current testing procedures leave much desired. The PCR tests require complicated deep throat or nasal swabs, which generally have to be taken by a trained healthcare professional. The antibody tests require blood samples and highly trained experts to analyze the samples. Finally, the antigen tests are still unproven.
A new study out of Yale University has found that saliva samples are better than the deep throat or nasal swabs in testing for the coronavirus. The study, which was led by the Yale School of Public Health at Yale New Haven Hospital, tested 44 inpatients and 98 health care workers. They found that saliva samples collected from just inside the mouth afforded higher detection sensitivity and reliability compared with the recommended deep throat/nasal swab approach. The researchers also found that with a self-sample collection of saliva there was less variability in the results. Furthermore, a swab is not required, the saliva can be directly expelled (spit) into a sterile container.
Anne Wyllie, an associate research scientist at the Yale School of Public Health and a member of its Public Health Modeling Unit who worked on this study, said:
"Taken together, our findings demonstrate that saliva is a viable and more sensitive alternative to nasopharyngeal swabs and could enable at-home self-administered sample collection for accurate large-scale SARS-CoV-2 testing."
Sources: CNN, Yale, medRxiv, ABC6
