It now looks like there is no point in waiting for antibody test kits to put the whole of Kerala under the scanner to detect signs of what has been called the "third stage of infection", silent transmission in the community.
After the shocking inaccuracies of the antibody kits sourced from China, Indian Council of Medical Research (ICMR) has suddenly developed cold feet about antibody tests.
Dr Raman R Gangakhedkar, chief of Epidemiology and Communicable Diseases at ICMR, said the antibody kits being developed now were first-generation ones that did not tell anything more about the disease (COVID-19) than was already known.
"We will use them but only when they become better and accurate," Dr Gangakhedkar said.
Therefore, it is highly unlikely that the ICMR would any time soon validate the antibody kits developed internally in Kerala - by Rajiv Gandhi Centre for Biotechnology (RGCB) and HLL Lifecare Ltd – and had reportedly been handed over to the ICMR for approval.
Kerala's hope, rapidly grounded
Though Kerala has ramped-up Reverse Transcription-Polymerase Chain Reaction (RT-PCR) tests, the State was banking on the wider use of antibody tests, which are both portable and quick to provide results, to check for community transmission.
"Antibody tests are necessary to check whether social spread has taken place, whether the third wave has started," said Dr B Ekbal, the head of the expert panel advising Kerala Government on tackling COVID-19.
Dr Ekbal said that the RGCB, once its product was given ICMR approval, could produce up to 75 lakh kits a month. He said that after meeting Kerala's requirements, the RGCB could sell the remaining to other states. "The RGCB has even put in place a marketing mechanism to sell the surplus kits," he said.
Dr Gangakhedkar, however, said the ICMR had not yet received any request from the RGCB for the validation of their kits.
Puncturing antibody test myths
The ICMR's top epidemiologist said the clamour for antibody tests were based on misconceptions. "Most people believe that antibody tests are going to diagnose infection early, and that it could be offered very conveniently at their homes. But these are not true," he said.
"Rapid tests, by and large and so far, are first generation tests. When you develop such tests for the first time, these are likely to be not so refined, and these can throw up results very late, only after two weeks of infection. So the utility is also zero," he said.
Dr Gangakhedkar said the tests could not also tell whether the antibodies detected were an armour against the disease or were protective antibodies. "We have no evidence to suggest that the antibodies that had been generated are protection against the disease or whether they would prevent a new infection from a similar virus in the future," he said, and added: "Even if there is protection, we don't know for how long the protection will last."
Uselessness of antibody tests
At this stage of evolution of COVID-19 understanding, therefore, antibody tests look futile.
"We don't want to use these tests if they are not going to tell anything more than we know now. Neither does it say anything about immune protection, nor could it diagnose COVID-19, nor could it provide results quickly. These tests cannot be used with a purpose as of now," Dr Gangakhedkar said.
Therefore, to pick up signs of community transmission, Kerala will have no choice but to use up more of its RT-PCR facilities, the standard tests now used across the country to detect the presence of the virus.
Kerala RT-PCR readiness
In fact, Kerala had already begun community surveillance using the RT-PCR testing method. Apart from the routine tests of suspected individuals, 300 additional samples are taken thrice a week – 900 a week – from panchayats where the epidemic is high and also from high-risk groups like heathcare workers, people with high social exposure, and the elderly.
In addition, the samples of patients visiting peripheral hospitals like primary health centres and taluk hospitals with respiratory distress and even influenza-like illnesses are also tested.
Dr Gangakhedkar said no other state had tested SARI (severe acute respiratory infection) patients the way Kerala had.
At the moment, the increased testing has not imposed any major strain on Kerala's RT-PCR testing capability. On February 18, Kerala had only 14 PCR machines. Now, it has 46.
There are three other critical items: swabs, reagent kits and RNA extraction kits. Kerala has a stock of 65,000 swabs, and it has five suppliers, both global and domestic, to source from.
As for the PCR kits, which holds the reagents to amplify the extracted DNA, there are 45,000 in stock. There are six steady suppliers, too.
The RNA extraction kits are the sole worry. There is stock of only 38,000, sourced from 12 suppliers. "Thousands are used every day," said Navjot Khosa, the managing director of Kerala Medical Services Corporation Limited (KMSCL). "But this is a dynamic number, not a static one. Since we have already placed an order for three lakh kits, the used ones will be gradually replenished," Khosa said.
