India tests 10 million samples for Covid-19, experts say more required

From 13 labs in the first week of February to 123 labs on March 24, India now has 1,100 testing labs in all states, and the numbers are only growing as ICMR continues to expand the testing laboratory network.

India has tested 10 million samples for the coronavirus disease (Covid-19) in the past five-and-a-half months, with at least 200,000 samples being tested between January 22 and July 5 on average daily in the 11,00 laboratories that were identified, upgraded or established across the country at a breakneck speed to ramp up testing and prevent the spread of infections.

Experts say India would need to test more as not even 1% of the country’s total population has currently been tested.(Parveen Kumar/HT photo)

Covid-19 testing labs in the country approved by the Indian Council of Medical Research (ICMR) are capable of performing about 350,000 tests a day currently, an increase from about 10,000 tests per day in early February. ICMR has been reiterating how developing an intelligent testing strategy helped India stay ahead of the Sars-CoV2 virus that causes Covid-19.

From 13 labs in the first week of February to 123 labs on March 24, India now has 1,100 testing labs in all states, and the numbers are only growing as ICMR continues to expand the testing laboratory network. Of the approved laboratories, 786 labs are in the government sector and 314 are private testing facilities.

ICMR has also collaborated with other science and research agencies such as the department of science and technology, department of biotechnology, Council of Scientific and Industrial Research, Defence Research and Development Organisation and the Department of Atomic Energy for use of their testing labs and developing research solutions.

Amitabh Kant, CEO of the government policy think tank Niti Aayog, emphasized the need for aggressive testing.

“…We can succeed against #Covid-19 only with 3T strategy of testing, tracing and treating. This is the moment to act, and to act fast,” Kant tweeted. Kant chairs the empowered group number 6 on coordinating with private sector, NGOs, and International Organisations for Covid-19-related response.

Experts also say that testing is crucial to determine the disease burden.

“Unless you test you cannot know the actual disease prevalence. Targeted approach is about being able to know the disease burden as exactly as possible, and we now have the expertise and technology at our disposal to break things down to the lowest level. Looking for syndromic cases or guessing cases on the basis of clinical assessment doesn’t make sense in today’s day and age when science has advanced significantly. We have the resources and it is a good idea to make use of them,” said Dr Lalit Kant, former head of the division of epidemiology, ICMR.

The national testing strategy is being constantly revised in line with the current trend of the outbreak.

Reverse transcriptase-polymerase chain reaction (RT-PCR) is the gold standard testing method for the Sars- CoV-2 diagnosis and is in place in all the identified laboratories for diagnosing the disease, says ICMR. To ramp up testing, ICMR has also been exploring other testing mechanisms for diagnosis along with RT-PCR testing.

“Testing remains a cornerstone in our fight against Covid-19 and therefore ramping up testing is essentially critical to track, trace and treat all cases of Covid-19,” said the director general of ICMR, Dr Blaram Bhargava, in one of its letters to the Union health secretary, Preeti Sudan, last month.

“Since the gold standard RT-PCR test has essential requirements in terms of biosafety and biosecurity as well as specialized equipment, ICMR had been exploring alternate, quick and reliable options for diagnosis of Covid-19.”

On June 15, ICMR validated first point of care rapid antigen test for Covid-19 diagnosis that states can deploy on the field in containment zones, hotspots and hospitals, and get results in a maximum 30 minutes as opposed to five hours in a conventional RT-PCR test.

This is the first such rapid test in the world that can be used for diagnosis as positive cases need not be confirmed through an RT-PCR test.

An antigen is a foreign molecule that induces an immune response in the body, especially the production of antibodies, and detecting its presence determines a present infection.

Apart from antigen testing, ICMR also included antibody-based (blood) tests for sero-surveillance.

“However, antibody tests are not suitable to diagnose live Covid-19 infections,” advises the ICMR.

The ICMR advisory says to start rapid antibody based blood tests for Covid-19 as a strategy for areas reporting clusters (containment zones) and in large migration gatherings and in, evacuees centres.

ICMR has developed guidelines ranging from the preparation of a network of government and private laboratories to ensure efficient validation and evaluation of new diagnostic kits.

ICMR is also considering other scale-up interventions such as moving to a 24x7 working model at existing labs, coordinating with states to increase staff for various functions including data-entry, re-deploying automated and manual RT-PCR machines already in the country to aid Covid-19 testing, and optimising in-lab processes such as RNA extraction to reduce the turnaround time between sample receipt and testing.

Experts say India would need to test more as not even 1% of the country’s total population has currently been tested.

“It is important to test more because you cannot devise strategies for the remaining 99% of the population by looking at statistics coming from just 1% of the country’s population,” says Dr T Jacob John, former virology head at the Christian Medical College, Vellore.