Optimizing testing for COVID-19 in India

Abstract

COVID-19 testing across India uses a mix of two types of tests. Rapid Antigen Tests (RATs) are relatively inexpensive point-of-care lateral-flow-assay tests, but they are also less sensitive. The reverse-transcriptase polymerase-chain-reaction (RT-PCR) test has close to 100% sensitivity and specificity in a laboratory setting, but delays in returning results, as well as increased costs relative to RATs, may vitiate this advantage.India-wide, about 49% of COVID-19 tests are RATs, but some Indian states, including the large states of Uttar Pradesh (pop. 227.9 million) and Bihar (pop. 121.3 million) use a much higher proportion of such tests. Here we show, using simulations based on epidemiological network models, that the judicious use of RATs can yield epidemiological outcomes comparable to those obtained through RT-PCR-based testing and isolation of positives, provided a few conditions are met. These are (a) that RAT test sensitivity is not too low, (b) that a reasonably large fraction of the population, of order 0.5% per day, can be tested, (c) that those testing positive are isolated for a sufficient duration, and that (d) testing is accompanied by other non-pharmaceutical interventions for increased effectiveness. We assess optimal testing regimes, taking into account test sensitivity and specificity, background seroprevalence and current test pricing. We find, surprisingly, that even 100% RAT test regimes should be acceptable, from both an epidemiological as well as a economic standpoint, provided the conditions outlined above are met.Author summaryUsing network models, we study optimal ways of combining low sensitivity, relatively inexpensive point-of-care rapid antigen tests for COVID-19 with higher sensitivity but more expensive laboratory RT-PCR tests. We take into account background seroprevalence and current test pricing for such tests in India, finding that even purely rapid antigen test-based regimes can produce the same reduction in overall infections that pure RT-PCR tests are capable of. This is provided one can test at scale and isolate those testing positive effectively, that the sensitivity of the rapid test is not too low and that non-pharmaceutical interventions proceed in parallel for increased effectiveness.

Will there be a third COVID-19 wave? A SVEIRD model-based study of India’s situation

“…They have used the SIR model for the prediction. This together with work on testing reported by Cherian et al [ 6 ] with a more complicated version of the SIRD model shows the necessity of more testing and a dependable source for people hospitalized or in-home isolation. In a new model-based analysis, including asymptomatic and undetected population, Agarwal et al [ 7 ] have shown the appearance of the peak for the second wave in different states of India quite accurately.…”

The INDSCI-SIM model for COVID-19 in India

“…Questions such as the issue of reinfections as a consequence of immune escape, of partial immunity from the ongoing vaccination program, of vaccine breakthroughs at a low rate and of the impacts of multiple lock-downs applied inhomogeneously throughout the country should factor into any further analysis of events after the end of the first wave of COVID-19 in India. These impact public health policy intimately, especially as they are relevant to both testing strategies and vaccination policies [115, 116]. It is here that we expect that well formulated and bench-marked models should be of substantial use, both to understand the past better as well as to project the future more accurately.…”

Building Sustainable Societies through Purpose-Driven Universities: A Case Study from Ashoka University (India)

“…Several research projects and programmes are being carried out within the state of Haryana by AU's faculty and students to engage the local communities. These initiatives address local issues such as streamlining the implementation of the state government's policies in the field of education, women's safety, health and sanitation, higher education and e-governance [79]; Stubble burning-a major cause of air pollution in North India [80]; optimising testing for COVID-19 [81]; conducting studies on archaeological sites [82].…”

“…From working on the mathematical model for optimising testing for COVID-19 in India to collaborating with different institutes, understanding the pandemic and lockdown's effects on the social, economic sector as well as on wide-range aspects of life-Ashoka's faculty's efforts in this field have been highlighted in scholarly works [81,95,96].…”