COVID-19 saliva diagnosis cheaper, faster alternative to swab testing, say scientists
New Delhi: A low-cost saliva test that will enable people to collect their own samples with minimal discomfort, without invasive nasal or throat swabs, could well be the way forward to detect the novel coronavirus, say scientists.
Giving a thumbs up to the alternative testing technology that is yet to be introduced in India, scientists said it would deliver results faster and more accurately and also minimise the risk for healthcare workers collecting samples.
The saliva-based COVID-19 diagnosis offers an improvement over standard nasopharyngeal swab methods because people can collect their own samples with ease -- simply spit into a sterile tube and mail it to a lab for processing.
"It is also unique because it does not require a separate nucleic acid (RNA) extraction step. This is significant because the extraction kits used for this step in other tests have been prone to shortages in the past, A R Anand, senior associate professor at Chennai's L&T Microbiology Research Centre, told PTI.
Noting that the saliva direct' test is easier to carry out, he said it needs only a few reagents and a real-time polymerase chain reaction (RT-PCR) machine.
Discussion on the technology intensified after the US Food and Drug Administration (FDA) this week gave the Yale School of Public Health emergency use authorisation for its Salivadirect' COVID-19 diagnostic test.
The FDA said in a statement that SalivaDirect does not require any special type of swab or collection device. A saliva sample, it said, can be collected in any sterile container.
Though saliva tests are yet to be approved in India for mass use, scientists such as Anand suggest the matter be explored further.
A fast-tracked study should be conducted in an Indian setting comparing the saliva RT-PCR tests with the nasopharyngeal RT-PCR tests before large-scale implementation in our country, Anand said.
An Indian Council of Medical Research (ICMR) scientist added that India is exploring the availability of kits and other aspects. At present, no kit is approved in India," he said on the condition of anonymity.
According to a recent study published in ICMR's Indian Journal of Medical Research, gargled water samples may be another viable alternative to swabs for detecting COVID-19, enabling easy self-collection and removing the need for trained healthcare workers for sample collection.
Asked about the saliva test cleared by the FDA, ICMR Director General Balram Bhargava on Wednesday told a parliamentary panel that taking samples from gargled water is already under consideration and further details will be available soon.
There are two types of diagnostic tests for COVID-19 testing, both using swabs from the nose and the throat.
The RT-PCR test, which can take hours or even days before a result, detects genetic material of the virus using a lab technique called polymerase chain reaction. The second diagnostic test, the antigen COVID-19 test, detects certain proteins in the virus. An antigen test can also produce results in minutes.
Saliva tests would be an improvement on both.
The collection does not involve material such as swabs -- which can be in short supply -- and the person doing the collection does not need as much training, Satyajit Rath, from New Delhi's National Institute of Immunology, told PTI.
Such systems also reduce the cost since we don't have to depend on one company. Saliva is a much easier sample to collect from patients, compared to nasopharyngeal swabs, which are a little invasive and cause some discomfort to patients, Anand added.
Vineeta Bal, an immunologist from Pune's Indian Institute of Science, Education and Research, said saliva tests might become easily accessible like rapid paper strip tests available for testing blood or urine glucose.
Hence, life can come closer to the normal' that we knew of before the pandemic. In India, some researchers are developing the tests for detection from saliva. But as far as I know they are far from reaching the market, Bal added.
Noting the pluses of the Yale saliva test, virologist Shahid Jameel pointed to the ease of sample collection and the reduced cost for extracting RNA, the genetic material of a virus. It would also lead to fewer false negative results.
Most false negative results in the RT-PCR test today are due to improper sampling from the nasopharyngeal area, which is also uncomfortable for the person being tested, Jameel, CEO of the Wellcome Trust/DBT India Alliance, a public charity that invests in building biomedical sciences, told PTI.
In addition to the Yale saliva test, Israel's Center for Geographic Medicine and Tropical Diseases has developed a test that aims to determine in less than a second whether a person is infected with the novel coronavirus.
Noting that the Israel test is yet to be approved, Jameel said it uses the scattering of light by virus particles in mouth washings to estimate both presence or absence, and quantity of virus particles in the sample.
This is based on obtaining data from a large number of positive and negative people and training an algorithm to pick the right scattering patterns. Besides the light source, this test uses artificial intelligence (AI) and machine learning, hoping to get better with time as more samples are analysed, Jameel explained.
Machine learning is an application of AI that provides systems the ability to automatically learn and improve from experience.
Both the tests will reduce time. The Yale test will only cut RNA extraction time as the rest of the process is the same. The Israel test is very quick, Jameel added.
Virologist T Jacob John agreed that the saliva test is a low-cost alternative.
Explaining one of the ways in which saliva test can work, he said, There is a process of viral genetic material (RNA) converted to DNA, which is then detected by a method different from PCR. It is called loop-mediated isothermal amplification', or LAMP, an original Japanese invention, John, former head of clinical virology at Christian Medical College, Vellore, told PTI.
LAMP is a cheaper PCR alternative previously used to detect outbreaks of zika and ebola in resource-poor countries.
The final reading is taken by colour reaction -- pink turning to yellow. The equipment is cheaper than PCR equipment If spit is collected, it avoids the use of special swabs which are in short supply, said John.
Israel and India are conducting trials here on a large sample of patients for four different kinds of technologies, including two COVID-19 tests that could give results in minutes from a saliva sample, according to a statement by the Israeli Embassy in Delhi.
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MP HC sets up judicial commission to probe water contamination in Indore
Indore (PTI): The Indore bench of Madhya Pradesh High Court on Tuesday set up a commission of inquiry comprising a former HC judge to probe the issue of water contamination in city's Bhagirathpura, saying the matter requires probe by an independent, credible authority and "urgent judicial scrutiny".
It also directed the commission to submit an interim report after four weeks from the date of commencement of proceedings.
A division bench of Justices Vijay Kumar Shukla and Alok Awasthi constituted the commission while hearing several public interest litigations (PILs) filed simultaneously regarding the deaths of several people in Bhagirathpura due to the consumption of contaminated water.
The HC reserved the order after hearing all the parties during the day, and released it late at night.
The state government on Tuesday told the HC that the deaths of 16 people in Indore's Bhagirathpura area was possibly linked to a month-long outbreak of vomiting and diarrhoea caused by contaminated drinking water.
The government presented an audit report of 23 deaths from the current gastroenteritis epidemic in Bhagirathpura before the bench, suggesting that 16 of these fatalities may have been linked to the outbreak of vomiting and diarrhoea caused by contaminated drinking water.
The report, prepared by a committee of five experts from the city's Government Mahatma Gandhi Memorial Medical College, stated that the deaths of four people in Bhagirathpura were unrelated to the outbreak, while no conclusion could be reached regarding the cause of death of three other people in the area.
During the hearing, the high court sought to know from the state government the scientific basis behind its report.
The division bench also expressed surprise at the state government's use of the term "verbal autopsy" in relation to the report, sarcastically stating that it had heard the term for the first time.
The HC expressed concern over the Bhagirathpura case, stating that the situation was "alarming," and noted that cases of people falling ill due to contaminated drinking water have also been reported in Mhow, near Indore.
In its order, the HC said the serious issue concerning contamination of the drinking water supply in Bhagirathpura area allegedly resulted in widespread health hazards to residents, including children and elderly persons.
According to the petitioners and media reports, death toll is about 30 till today, but the report depicts only 16 without any basis or record, it said.
It is averred that sewage mixing, leakage in the pipeline, and failure of civic authorities to maintain potable water standards have led to the outbreak of water-borne diseases. Photographs, medical reports, and complaints submitted to the authorities prima facie indicate a matter requiring urgent judicial scrutiny, the HC said.
"Considering the gravity of the allegation and affecting the right to life under Article 21 of the Constitution of India and the need for an independent fact-finding exercise, the Court is of the opinion that the matter requires investigation by an independent, credible authority," it said.
"Accordingly, we appoint Justice Sushil Kumar Gupta, former judge of the Madhya Pradesh High Court, a one-man commission of inquiry into the issues relating to water contamination in Bhagirathpura, Indore, and its impact on other areas of the city," the HC added.
As per the order, the commission shall inquire into and submit a report on the cause of contamination -- whether the drinking water supplied to Bhagirathpura was contaminated; and the source and nature of contamination (sewage ingress, industrial discharge, pipeline damage etc).
The panel will also probe the number of actual deaths of affected residents on account of contaminated water; find out the nature of disease reported and adequacy of medical response and preventive measures; suggest immediate steps required to ensure safe drinking water as well as long-term infrastructural and monitoring reforms.
It will also identify and fix responsibility upon the officers and officials found prima facie responsible for the Bhagirathpura water contamination incident, and suggest guidelines for compensation to affected residents, particularly vulnerable sections.
The commission shall have powers of a civil court for the purpose of summoning officials and witnesses; calling up records from the government department, hospitals, laboratories and civic bodies; ordering water quality testing through accredited laboratories; conducting spot inspections.
All state authorities involving district administration, Indore Municipal Corporation, public health engineering department and Madhya Pradesh Pollution Control Board shall extend full co-operation and provide records as sought by the commission, it said.
The state government shall provide office space, staff, and logistical support to the commission, it said.
During the hearing in the day, the state government also presented a status report to the court in this matter.
According to reports, a total of 454 patients were admitted to local hospitals during the vomiting and diarrhea outbreak, of whom 441 have been discharged after treatment, and 11 are currently hospitalised.
According to officials, due to a leak in the municipal drinking water pipeline in Bhagirathpura, sewage from a toilet was also mixed in the water.
