Covid 19 update: Govt testing strategy focuses on speed
The strategy is the subject of a paper, ‘Strategic Planning To Augment The Testing Capacity For Covid-19 in India’, published in the Indian Journal of Medical Research and authored by scientists at the Indian Council of Medical Research (ICMR), the country’s apex biomedical research body.Updated: Apr 29, 2020, 00:53 IST
The government’s strategy to scale up testing for the coronavirus disease (Covid-19) hinges on the procurement of automatic RNA extraction platforms, corralling existing RT-PCR machines from institutes across the country and working on in 24-hour shifts, a recent study has outlined.
The strategy is the subject of a paper, ‘Strategic Planning To Augment The Testing Capacity For Covid-19 in India’, published in the Indian Journal of Medical Research and authored by scientists at the Indian Council of Medical Research (ICMR), the country’s apex biomedical research body.
The paper details short and medium- term measures that can increase daily testing capacity in public-sector laboratories and facilities to 100,000-120,000 samples but adds that the most effective interventions could take until the middle of May or the first week of June to fully operationalise.
In the first week of April, ICMR announced its intention of gradually increasing the testing capacity to 100,000 tests daily.
The main measures proposed are redeployment of 42 manual RT-PCR machines from other research units, procurement of kits that can do the screening and confirmation tests in one run, operationalising high-throughput automated platforms that can conduct 140 tests a day, decentralising the laboratory network, utilising machines used for tuberculosis diagnosis and procurement of automatic RNA extraction machines.
Of the measures, the automatic RNA machines that eliminate the need for time-consuming manual extraction of RNA of the virus – a key part of the RT-PCR test – and high-throughput platforms that can process more material were found to the most effective.
“Installation and/or operationalization of automated RNA extraction platforms supported by requisite extraction kits…could increase testing capacity by 1.5-2 times within the same operating hours,” noted the scientists.
The paper evaluated the measures on three time scales: 8-hour working day (conservative), 16-hour working day (moderate) and 24-hour working day (aggressive). Only in the third scenario did the capacity increase to 100,000-120,000 daily.
“It is important to note that utilization of the scaled-up testing capacity will require deployment of additional workforce, procurement of corresponding commodities for testing and scale-up of sample collection and transportation efforts,” the authors note.
The most effective intervention was the automated RNA extraction kits that boosted testing capacity by 40%-50% in various work-cycle scenarios. But the paper cautioned that it was a medium-term measure that could take up to May 23 to fully operationalize. The installation of high-throughput machines – two of which are operational in Delhi and Bhubaneswar, according to the ICMR – could also take up to June 1 to fully operationalise.
India has gradually ramped up its RT-PCR testing capacity – the standard swab test that can tell if a person is suffering from the disease at the point of testing – since the first week of April. It is now the only form of testing for Covid-19 in India after the government found Chinese rapid testing kits – used to check if a person’s blood has antibodies – faulty and decided to return them.
As of April 25, India’s daily testing capacity stood at 45,352 samples, but a break-up of government and private facilities was unavailable. This represented a nearly 10-fold jump from the figures on March 25, when the ongoing national lockdown was imposed. But experts have flagged that per-capita testing, which stands at 529 per million, is among the lowest in the world.
At present, India has 283 government labs testing for Covid-19 and 94 private labs, and another 30-50 facilities are in the pipeline, said ICMR media coordinator LK Sharma. Labs have a minimum capacity of 90 tests per cycle, but some can test up to 250, he added. “Many of the recommendations have already been implemented. In some labs, two shifts, totaling to 16-hour workday, have already started. The capacity can be increased as per the sample load.”
In a recent modelling study, a group of Indian scientists flagged the importance of scaling up testing, especially when the government is considering lifting the lockdown.
“Our model and various other studies have already established the relation between the duration of the lockdown and the number of tests. Thus, it is important that we increase the testings substantially and look at the ratio of the number of positive tests and the total number of tests. For example, if after performing 100 tests, you find that 10 of them are positive, this ratio is 10/100 = 0.1. A good rule of thumb is to increase testings to such an extent that this ratio goes below some prescribed threshold, say 1%. This means that you have now detected almost all the infected cases, and lifting the lockdown is possible,” said Snehal Shekatkar, a professor at the Centre for Modelling Studies at Savitribai Phule Pune University and one of the authors of the study.