High-frequency screening combined with diagnostic testing for control of SARS-CoV-2 in high-density settings: an economic evaluation of resources allocation for public health benefit

Abstract

SARS-CoV-2 spreads quickly in dense populations, with serious implications for universities, workplaces, and other settings where exposure reduction practices are difficult to implement. Rapid screening has been proposed as a tool to slow the spread of the virus; however, many commonly used diagnostic tests (e.g., RT-qPCR) are expensive, difficult to deploy (e.g., require a nasopharyngeal specimen), and have extended turn-around times. We evaluated testing regimes that combined diagnostic testing using qPCR with high-frequency screening using a novel reverse-transcription loop-mediated isothermal amplification (RT-LAMP, herein LAMP) assay. We used a compartmental susceptible-exposed-infectious-recovered (SEIR) model to simulate screening of a university population. We also developed a Shiny application to allow administrators and public health professionals to develop optimal testing strategies given site-specific assumptions about testing investment, target population, and cost. The frequency of screening, especially when pooling samples, was more important for minimizing epidemic size than test sensitivity, behavioral compliance, contact tracing capacity, and time between testing and results. Our results suggest that when testing budgets are limited, it is safer and more cost-effective to allocate the majority of funds to screening. Rapid, cost-effective, and scalable screening tests, like LAMP, should be viewed as critical components of SARS-CoV-2 testing in high-density populations.

Empirical evidence to understand the human factor for effective rapid testing against SARS-CoV-2

“…The participants further rated whether they would show a certain behavior given a positive home test result (isolate and, until the result is verified, get a free PCR test, informing close contacts of the past 14 d, and do a second rapid test; 1 = definitely not to 7 = definitely) and indicated whether they think reporting of positive home test results is legally mandated (yes/no/don’t know). For reporting, the variables were recoded as no/disagree ( 1 – 3 ), unsure/undecided ( 4 ), and yes/agree ( 5 – 7 ).…”

“…Rapid testing with antigen tests, and the subsequent isolation of individuals who tested positive, is a strategy for controlling and potentially decreasing the disease dynamics in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic—given that a relevant part of the population gets tested regularly ( 1 – 7 ). Some governments offer free weekly tests to asymptomatic people ( 8 ), and home tests are increasingly available in shops to everyone.…”

Experiences with regular testing of students for SARS-CoV-2 in primary and secondary schools: results from a cross-sectional study in two Norwegian counties, autumn 2021

“…Modelling studies have found that testing twice a week can reduce the attack rate and transmission of COVID-19 [4,9]. In another study modelling the impact of different testing regimens in the university setting, the authors suggested that higher frequency of testing could further reduce the size of the epidemic [5]. Results from primary and secondary schools in our study suggest that increasing testing frequency to three tests per week may negatively impact compliance.…”

COVID-19 Test Frequency Versus Test Sensitivity in Disrupting SARS-CoV-2 Transmission: A Review of Statistical Modeling Simulations

“…Several authors analyzed the impact of various COVID-19 testing approaches with simulations of a college campus [20][21][22][23][24][25][26][27] . Paltiel et al proposed a modified SEIR model to demonstrate the effect of test frequency and sensitivity on infections and isolation practices in a university environment of 5,000 students with 10 initial infections.…”

“…They evaluated the utility of screening programs testing 0-20% of the population per day with test sensitivity ranging from 60-90%. Rogers et al demonstrated test frequency was the most important factor in reducing infections compared to test sensitivity and behavioral compliance 26 . Hartvigsen also applied SIR to model networks of transmission in a university population.…”