Self-Collected Saliva Sample Can Effectively Diagnose COVID-19: Study

Washington: A study published in the Journal of Molecular Diagnostics, reveals that COVID-19 can be effectively diagnosed with self-collected saliva samples that are capable of detecting SARS-CoV-2 genetic material in a rate similar to that of nasopharyngeal and oropharyngeal swabs. The rate of detection using saliva samples was similar across different testing platforms, and saliva samples remained stable for up to 24 hours when stored with ice packs or at room temperature, according to a new study by Elsevier, Researchers at Memorial Sloan Kettering Cancer Center (MSK).

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Lead investigator Esther Babady, PhD, D (ABMM), FIDSA, director of the Clinical Microbiology Service at Memorial Sloan Kettering Cancer Center, New York, NY, USA said,

The current pandemic has placed a significant strain on the supply chain, from swabs to the personal protective equipment (PPE) healthcare workers need to safely collect samples.

“The use of self-collected saliva has the potential to minimize healthcare worker exposure and decrease the need for specialised collection devices, such as swabs and viral transport media,” added Esther Babady.

The study that was conducted at MSK in New York City at the peak of the regional outbreak between April 4 and May 11, 2020 involved 285 MSK employees as participants who needed to be tested for COVID-19 because they had symptoms of the virus or had been exposed to someone who had the virus.

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Each participant provided paired samples: a nasopharyngeal swab and oral rinse; a nasopharyngeal swab and a saliva sample; or an oropharyngeal swab and a saliva sample. All samples to be tested were stored at room temperature and transported to the laboratory within two hours. The agreement between the saliva test and the oropharyngeal swab was 93 percent, with a sensitivity of 96.7 percent. In comparison with the nasopharyngeal swab, the agreement of the saliva test was 97.7 percent, with a sensitivity of 94.1 percent.

Oral rinses were only 63 percent effective in detecting the virus, with an overall agreement with nasopharyngeal swab of only 85.7 percent. To test for stability, saliva samples and nasopharyngeal samples with a range of viral loads were stored in a transport cooler at 4deg C or at room temperature. No significant difference in virus concentration was detected in any samples at the time of collection, eight hours later, and 24 hours later. These results were validated on two commercial SARS-CoV-2 PCR platforms, and overall agreement between the different testing platforms was over 90 percent.

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Dr. Babady noted that validation of sample self-collection methods holds great promise for broad testing strategies that would mitigate infection risk and PPE resource utilization. “The current ‘test, track, and trace’ public health approach to surveillance relies heavily on testing for both diagnosis and surveillance. The use of self-collected saliva provides a cheaper and less invasive option for viable sample collection. It’s certainly easier to spit in a cup twice a week than undergoing frequent nasopharyngeal swabs,” she stated.

This can improve patient compliance and satisfaction particularly for surveillance testing, which requires frequent sample collection. Since we also showed that the virus was stable at room temperature for at least 24 hours, saliva collection has potential for use at home, she added.

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(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

NDTV – Dettol Banega Swasth India campaign is an extension of the five-year-old Banega Swachh India initiative helmed by Campaign Ambassador Amitabh Bachchan. It aims to spread awareness about critical health issues facing the country. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign highlights the importance of nutrition and healthcare for women and children to prevent maternal and child mortality, fight malnutrition, stunting, wasting, anaemia and disease prevention through vaccines. Importance of programmes like Public Distribution System (PDS), Mid-day Meal Scheme, POSHAN Abhiyan and the role of Aganwadis and ASHA workers are also covered. Only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and become a Swasth or healthy India. The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene.