Indian researchers start trials on saliva-based Covid-19 testing

MUMBAI: India may soon be able to carry out saliva-based tests for Covid-19 diagnosis if the government approves the process that is considered safer for healthcare workers and less discomforting for individuals.

The Medanta Institute of Education and Research in Gurgaon, Mumbai-based diagnostics company TransAsia Bio, and Pune’s Mylab are among the entities that are trying to get this testing method validated by demonstrating that analysis of saliva samples is as accurate as nasopharyngeal swab collection.

They said the process will save resources and time while protecting healthcare professionals from possible exposure to the virus.

The current method of sample collection requires healthcare workers to insert a tool into the nose and throat of an individual. In the saliva-based method, individuals spit into a collection kit, which is handed over to labs.

The saliva tests are not rapid or at-home tests and they follow the conventional molecular test that is the gold standard for Covid-19 diagnosis. The US Food and Drug Administration has given emergency approval for five saliva-based tests for diagnosing Covid-19 in the US.

“We have completed our trial and found that saliva is an equally good sample as nasopharyngeal for RT PCR (reverse transcriptase polymerase chain reaction) test, with much less problems to the patient and healthcare professionals,” said Vikas Deswal, consultant – internal medicine, at Medanta Hospital in Gurgaon.

Deswal is one of the researchers leading the prospective study to compare the sensitivity and specificity of salivary-based samples and nasopharyngeal samples in diagnosis of Covid-19.

“We collected the samples by a drooling method in a tube... in fact, in our observation, the accuracy was better than the present method of testing,” Deswal said.

The Medanta researchers will publish their study in a medical journal and plan to approach the Indian Council of Medical Research in two weeks to seek approval for this method of sample collection.

TransAsia Bio is starting a trial to get saliva samples validated by ICMR. It will collect 200 positive and 200 negative samples of individuals who did the RT PCR tests.

“We will be doing an internal evaluation and in a month’s time will reach out to the authorities with our findings,” Suresh Vazirani, MD of TransAsia Bio, told ET.

The USFDA said earlier this month that testing saliva eliminates the need for nasopharyngeal swabs, which have also been prone to shortages, and alleviates the patient discomfort associated with these swabs.

“Since the saliva sample is self-collected under the observation of a healthcare professional, it could also potentially lower the risk posed to healthcare workers responsible for sample collection,” it said.