Clinical and Economic Effects of Widespread Rapid Testing to Decrease SARS-CoV-2 Transmission

Proceedings of the Clinical Microbiology Open 2023: discussions about pandemic preparedness

The 4th Clinical Microbiology Open (CMO) took place in Carlsbad, California, on 10 and 11 February 2023. This event facilitated discussion between clinical and public health laboratory directors, government agencies, and industry representatives from the companies that make up ASM's Corporate Council. While many topics were discussed, much of the discussion focused on pandemic preparedness. There were four major questions addressed: (i) When is the perfect the enemy of good in pandemic testing? (ii) What other types of pathogens might cause another pandemic and how would this affect laboratory response? (iii) What research is needed to better understand the effectiveness of the pandemic response? (iv) What have we learned about the utility of self and at-home testing in future pandemics? This review serves as a summary of these discussions.

Estimating the impact of COVID-19 self-test availability and modifications in test-strategy on overall test uptake using an experimental vignette study

To inform future Dutch COVID-19 testing policies we did an experimental vignette study to investigate whether inclusion of the less reliable lateral flow tests (self-tests) would change test-uptake sufficiently to improve population-level test sensitivity. A representative sample (n = 3,270) participated in a 2-by-2 online experiment to evaluate the effects of test-guidelines including self-testing advice (IV1), and the effects of self-test availability (IV2) on expected test uptake (PCR test, self-test or no test) and sensitivity of the overall test strategy (primary outcome). Across four scenarios, changing test advice did not affect expected testing behaviour. Self-test availability, however, increased the timeliness of testing, the number of people testing, and overall test strategy sensitivity. Based on these findings, we recommend that (national) policy facilitates a supply of self-tests at home, for example through free and pro-active distribution of test-kits during a pandemic. This could substantially enhance the chances of timely detecting and isolating patients.

In Support of Universal Admission Testing for SARS-CoV-2 During Significant Community Transmission

Many hospitals have stopped or are considering stopping universal admission testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We discuss reasons why admission testing should still be part of a layered system to prevent hospital-acquired SARS-CoV-2 infections during times of significant community transmission. These include the morbidity of SARS-CoV-2 in vulnerable patients, the predominant contribution of presymptomatic and asymptomatic people to transmission, the high rate of transmission between patients in shared rooms, and data suggesting surveillance testing is associated with fewer nosocomial infections. Preferences of diverse patient populations, particularly the hardest-hit communities, should be surveyed and used to inform prevention measures. Hospitals' ethical responsibility to protect patients from serious infections should predominate over concerns about costs, labor, and inconvenience. We call for more rigorous data on the incidence and morbidity of nosocomial SARS-CoV-2 infections and more research to help determine when to start, stop, and restart universal admission testing and other prevention measures.

Optimizing COVID-19 testing strategies on college campuses: Evaluation of the health and economic costs

Colleges and universities in the US struggled to provide safe in-person education throughout the COVID-19 pandemic. Testing coupled with isolation is a nimble intervention strategy that can be tailored to mitigate the changing health and economic risks associated with SARS-CoV-2. We developed a decision-support tool to aid in the design of university-based screening strategies using a mathematical model of SARS-CoV-2 transmission. Applying this framework to a large public university reopening in the fall of 2021 with a 60% student vaccination rate, we find that the optimal strategy, in terms of health and economic costs, is twice weekly antigen testing of all students. This strategy provides a 95% guarantee that, throughout the fall semester, case counts would not exceed twice the CDC's original high transmission threshold of 100 cases per 100k persons over 7 days. As the virus and our medical armament continue to evolve, testing will remain a flexible tool for managing risks and keeping campuses open. We have implemented this model as an online tool to facilitate the design of testing strategies that adjust for COVID-19 conditions as well as campus-specific populations, resources, and priorities.

Assessment of the detection accuracy of SARS-CoV-2 rapid antigen test in children and adolescents: An updated meta-analysis

BACKGROUND

Real-time and appropriate antigen tests play a pivotal role in preventing severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. However, a previous meta-analysis reported that the antigen test had lower sensitivity for the detection of SARS-CoV-2 in children. To provide a comprehensive evaluation of diagnostic efficiency, we performed an updated meta-analysis to assess the detection accuracy of SARS-CoV-2 antigen tests stratified by days after symptom onset and specimen type in children and adolescents.

METHODS

We comprehensively searched for appropriate studies in the PubMed, Embase, and Cochrane Library databases. Studies on the diagnostic accuracy of antigen tests for SARS-CoV-2 in children and adolescents were included. The relevant data of the included studies were extracted to construct a 2 × 2 table on a per-patient basis. The overall sensitivity and specificity of the SARS-CoV-2 antigen tests were estimated using a bivariate random-effects model.

RESULTS

Seventeen studies enrolling 10 912 patients were included in the present meta-analysis. For the detection accuracy of SARS-CoV-2 antigen tests, the meta-analysis generated a pooled sensitivity of 77.9% (95% confidence interval [CI]: 67.3%-85.8%) and a pooled specificity of 99.6% (95% CI: 98.9%-99.8%). The subgroup analysis of studies that examined antigen tests in symptomatic participants ≦7 days after symptom onset generated a pooled sensitivity of 79.4% (95% CI: 47.6%-94.2%) and a pooled specificity of 99.4% (95% CI: 98.2%-99.8%). Another subgroup analysis of studies that evaluated nasal swab specimens demonstrated a pooled sensitivity of 80.1% (95% CI: 65.0%-89.7%) and a pooled specificity of 98.5% (95% CI: 97.3%-9.2%).

CONCLUSION

Our findings demonstrated that the antigen test performed using nasal swab specimens exhibited high sensitivity for the detection of SARS-CoV-2 within 7 days after symptom onset. Therefore, antigen testing using nasal swabs may be effective in blocking SARS-CoV-2 transmission in children.

Cost of the COVID-19 pandemic versus the cost-effectiveness of mitigation strategies in EU/UK/OECD: a systematic review

OBJECTIVES

The economic burden of COVID-19 pandemic is substantial, with both direct and indirect costs playing a significant role.

DESIGN

A systematic literature review was conducted to estimate the cost of the COVID-19 pandemic and the cost-effectiveness of pharmaceutical or non-pharmaceutical interventions. All cost data were adjusted to the 2021 Euro, and interventions compared with null.

DATA SOURCES

Ovid MEDLINE and EMBASE were searched from January 2020 through 22 April 2021.

ELIGIBILITY CRITERIA

Studies regarding COVID-19 outbreak or public health preparedness measures or interventions with outcome measures related to the direct and indirect costs for disease and preparedness and/or response in countries of the European Union (EU), the European Economic Area (EEA), the UK and the Organisation for Economic Co-operation and Development (OECD) of all relevant epidemiological designs which estimate cost within the selected time frame were considered eligible.

DATA EXTRACTION AND SYNTHESIS

Studies were searched, screened and coded independently by two reviewers with high measure of inter-rater agreement. Data were extracted to a predefined data extraction sheet. The risk of bias was assessed using the Consensus on Health Economic Criteria checklist.

RESULTS

We included data from 41 economic studies. Ten studies evaluated the cost of the COVID-19 pandemic, while 31 assessed the cost-benefit of public health surveillance, preparedness and response measures. Overall, the economic burden of the COVID-19 pandemic was found to be substantial. Community screening, bed provision policies, investing in personal-protective-equipment and vaccination strategies were cost-effective. Physical distancing measures were associated with health benefits; however, their cost-effectiveness was dependent on the duration, compliance and the phase of the epidemic in which it was implemented.

CONCLUSIONS

COVID-19 pandemic is associated with substantial short-term and long-term economic costs to healthcare systems, payers and societies, while interventions including testing and screening policies, vaccination and physical distancing policies were identified as those presenting cost-effective options to deal with the pandemic, dependent on population vaccination and the Re at the stage of the pandemic.

Assessment of a SARS-CoV-2 population-wide rapid antigen testing in Italy: a modeling and economic analysis study

BACKGROUND

This study aimed to compare the cost-effectiveness of coronavirus disease 2019 (COVID-19) mass testing, carried out in November 2020 in the Italian Bolzano/Südtirol province, to scenarios without mass testing in terms of hospitalizations averted and quality-adjusted life-year (QALYs) saved.

METHODS

We applied branching processes to estimate the effective reproduction number (Rt) and model scenarios with and without mass testing, assuming Rt = 0.9 and Rt = 0.95. We applied a bottom-up approach to estimate the costs of mass testing, with a mixture of bottom-up and top-down methodologies to estimate hospitalizations averted and incremental costs in case of non-intervention. Lastly, we estimated the incremental cost-effectiveness ratio (ICER), denoted by screening and related social costs, and hospitalization costs averted per outcome derived, hospitalizations averted and QALYs saved.

RESULTS

The ICERs per QALY were €24 249 under Rt = 0.9 and €4604 under Rt = 0.95, considering the official and estimated data on disease spread. The cost-effectiveness acceptability curves show that for the Rt = 0.9 scenario, at the maximum threshold willingness to pay the value of €40 000, mass testing has an 80% probability of being cost-effective compared to no mass testing. Under the worst scenario (Rt = 0.95), at the willingness to pay threshold, mass testing has an almost 100% probability of being cost-effective.

CONCLUSIONS

We provide evidence on the cost-effectiveness and potential impact of mass COVID-19 testing on a local healthcare system and community. Although the intervention is shown to be cost-effective, we believe the initiative should be carried out when there is initial rapid local disease transmission with a high Rt, as shown in our model.

Proportion of Respiratory Syncytial Virus, SARS-CoV-2, Influenza A/B, and Adenovirus Cases via Rapid Tests in the Community during Winter 2023-A Cross Sectional Study

Respiratory infections constitute a major reason for infants and children seeking medical advice and visiting health facilities, thus remaining a significant public threat with high morbidity and mortality. The predominant viruses causing viral respiratory infections are influenza A and B viruses (Flu-A, Flu-B), respiratory syncytial virus (RSV), adenovirus and coronaviruses. We aimed to record the proportion of RSV, SARS-CoV-2, influenza A/B and adenovirus cases with rapid antigen tests and validate the results with RT-PCR assays of upper respiratory specimens with a wide range of viral loads and (co)-infection patterns in children. Clinical samples were collected from early symptomatic children (presenting with fever and/or cough and/or headache within 5-7 days). The surveillance program was conducted in five private pediatric dispensaries and one pediatric care unit, from 10 January 2023 to 30 March 2023 in central Greece. The total sample of specimens collected was 784 young children and infants, of which 383 (48.8%) were female and 401 were male (51.2%). The mean age of participants was 7.3 + 5.5 years. The sensitivity of the FLU A & B test was 91.15% (95% CI: 84.33-95.67%), and the specificity was 98.96% (95% CI: 97.86-99.58%). The sensitivity and specificity of the adenovirus and RSV test was {92.45% (95% CI: 81.79-97.91%), 99.32% (95% CI: 98.41-99.78%)} and {92.59% (95% CI: 75.71-99.09%), 99.47% (95% CI: 98.65-99.86%)} respectively. Lastly, the sensitivity of the SARS-CoV-2 test was 100.00% (95% CI: 79.41-100.00%) and the specificity was 99.74% (95% CI: 99.06-99.97%). We recorded a proportion of 14.3% and 3.44% for influenza A and B, respectively, followed by a proportion of 6.9% for adenovirus, a proportion of 3.7% for RSV, and finally, a proportion of 2.3% for SARS-CoV-2. The combination of a new multiple rapid test with multiple antigens will probably be a useful tool with a financial impact for health systems targeting the early detection and appropriate treatment of respiratory infections in emergency departments in primary health care facilities.

A Critical Study on DNA Probes Attached to Microplate for CRISPR/Cas12 Trans-Cleavage Activity

CRISPR/Cas12-based biosensors are emerging tools for diagnostics. However, their application of heterogeneous formats needs the efficient detection of Cas12 activity. We investigated DNA probes attached to the microplate surface and cleaved by Cas12a. Single-stranded (ss) DNA probes (19 variants) and combined probes with double-stranded (ds) and ssDNA parts (eight variants) were compared. The cleavage efficiency of dsDNA-probes demonstrated a bell-shaped dependence on their length, with a cleavage maximum of 50%. On the other hand, the cleavage efficiency of ssDNA probes increased monotonously, reaching 70%. The most effective ssDNA probes were integrated with fluorescein, antibodies, and peroxidase conjugates as reporters for fluorescent, lateral flow, and chemiluminescent detection. Long ssDNA probes (120-145 nt) proved the best for detecting Cas12a trans-activity for all of the tested variants. We proposed a test system for the detection of the nucleocapsid (N) gene of SARS-CoV-2 based on Cas12 and the ssDNA-probe attached to the microplate surface; its fluorescent limit of detection was 0.86 nM. Being united with pre-amplification using recombinase polymerase, the system reached a detection limit of 0.01 fM, thus confirming the effectiveness of the chosen ssDNA probe for Cas12-based biosensors.

The intersectionality-based policy analysis framework: demonstrating utility through application to the pre-vaccine U.S. COVID-19 policy response

Few guidelines exist for the development of socially responsible health policy, and frameworks that balance considerations of data, strategy, and equity are limited. The Intersectionality-Based Policy Analysis (IBPA) framework utilizes a structured questioning process to consider problems and policies, while applying guiding principles of equity, social justice, power, intersectionality, and diversity of knowledge and input. We apply the IBPA framework's guiding principles and questions to the pre-vaccine U.S. COVID-19 policy response. Results suggest the IBPA approach is a promising tool for integrating equity considerations in the development of policy solutions to urgent US public health challenges, including the COVID-19 pandemic. We found the IBPA framework particularly useful in differentiating between problems or policies and representations of problems or policies, and in considering the impacts of representations on different groups. The explicit inclusion of short-, medium- and long-term solutions is a reminder of the importance of holding a long-term vision of the equitable public health system we want while working towards immediate change.

Facilitators and barriers to use rapid antigen test for SARS-CoV-2 among community-dwelling older adults in Hong Kong: A population-based cross-sectional random telephone survey

Faster diagnosis of Coronavirus disease 2019 (COVID-19) is crucial for surveillance, prompt implementation of infection control measures and adequate patient care among older adults. This study investigated the behavioral intention to use Rapid Antigen Tests (RAT) and associated factors among older adults in Hong Kong for health monitoring and when having COVID-19-like symptoms. This was a population-based cross-sectional random telephone survey of 370 Chinese-speaking adults aged ≥65 years. The behavioral intention to use RAT was the main outcome, and logistic regression models were used to assess the associated factors, using SPSS (version 26.0.). Results indicate that among the participants, 90.3% had used RAT, of which 21.6% obtained positive results. The common challenges faced when using RAT included: difficulty choosing the right RAT kit, uncertainty about how to use RAT, and not knowing what to do after getting a positive result. Additionally, 27.3% intended to use RAT regularly for health status monitoring without any symptoms, while 87.0% if they had COVID-19-like symptoms. After adjustment for significant background characteristics, positive attitudes, perceiving Hong Kong government and their children and/or other family members would support them using RAT, belief that RAT health promotion materials were helpful to understand how to use RAT and thoughtful consideration of the veracity of COVID-19 specific information were associated with higher behavioral intention to use RAT both when having no symptoms and in presence of COVID-19-like symptoms. Having negative attitudes toward RAT was associated with a lower intention of RAT use only when having no symptoms. Addressing difficulties faced when using RAT, strengthening positive attitudes, involving significant others and empowering with adequate information-veracity evaluating skills are potentially vital strategies to increase RAT use among older adults.

Multicenter evaluation of a simple and sensitive nucleic acid self-testing for SARS-CoV-2

A rapid and accurate COVID-19 diagnosis is a prerequisite for blocking the source of infection as soon as possible and taking the appropriate medical action. Herein, we developed GeneClick, a device for nucleic acid self-testing of SARS-CoV-2, consisting of three modules: a sampling kit, a microfluidic chip-based disposable cartridge, and an amplification reader. In addition, we evaluated the clinical performance of GeneClick using 2162 nasal swabs collected at three medical institutions, using three commercial RT-qPCR kits and an antigen self-test as references. Compared to RT-qPCR, the sensitivity and specificity of the GeneClick assay were 97.93% and 99.72%, respectively, with a kappa value of 0.979 (P ​< ​0.01). Of the 2162 samples, 2076 were also tested for SARS-CoV-2 antigens. Among the 314 positive samples identified by GeneClick assay, 63 samples were undetected by antigen tests. Overall, the GeneClick nucleic acid self-test demonstrated higher accuracy than the antigen-based detection. Based on the additional features, including simple operation, affordable price, portable device, and reliability of smartphone APP-driven sampling and result reporting, GeneClick offers a powerful tool for field-based SARS-CoV-2 detection in primary healthcare institutions or at-home use.

Impact of the COVID-19 Pandemic on the US healthcare system

The COVID-19 epidemic had an enormous effect on the health of millions of individuals worldwide and the global economy. A shortage of doctors, nurses, personal protective equipment, and medicines was seen globally. The pandemic drew attention to limitations in the healthcare sector of the United States of America. The massive rise in the daily number of cases, more usage of ICU facilities and all the treatment modalities, and increased overtime compensation for the staff negatively impacted the hospital’s finances. This also affected the mental and physical health of all the healthcare workers. Through additional funding from federal relief legislation and the relaxation of many regulatory requirements, the federal, state, and local governments took significant steps to address the need for prevention and treatment services that arose from COVID-19 and the disruptions in healthcare delivery and finances resulting from the pandemic. Congress enacted the Coronavirus Aid, Relief, and Economic Security Act, or CARES Act, on March 27th, 2020. This measure appropriated $2.2 trillion to offer immediate and direct economic assistance to Americans affected by the COVID-19 outbreak.

Experiences of Health Departments on Community Engagement and Implementation of a COVID-19 Self-testing Program

CONTEXT

Health departments (HDs) work on the front lines to ensure the health of their communities, providing a unique perspective to public health response activities. Say Yes! COVID Test (SYCT) is a US federally funded program providing free COVID-19 self-tests to communities with high COVID-19 transmission, low vaccination rates, and high social vulnerability. The collaboration with 9 HDs was key for the program distribution of 5.8 million COVID-19 self-tests between March 31 and November 30, 2021.

OBJECTIVE

The objective of this study was to gather qualitative in-depth information on the experiences of HDs with the SYCT program to better understand the successes and barriers to implementing community-focused self-testing programs.

DESIGN

Key informant (KI) interviews.

SETTING

Online interviews conducted between November and December 2021.

PARTICIPANTS

Sixteen program leads representing 9 HDs were purposefully sampled as KIs. KIs completed 60-minute structured interviews conducted by one trained facilitator and recorded.

MAIN OUTCOME MEASURES

Key themes and lessons learned were identified using grounded theory.

RESULTS

Based on perceptions of KIs, HDs that maximized community partnerships for test distribution were more certain that populations at a higher risk for COVID-19 were reached. Where the HD relied predominantly on direct-to-consumer distribution, KIs were less certain that communities at higher risk were served. Privacy and anonymity in testing were themes linked to higher perceived community acceptance. KIs reported that self-test demand and distribution levels increased during higher COVID-19 transmission levels.

CONCLUSION

HDs that build bridges and engage with community partners and trusted leaders are better prepared to identify and link high-risk populations with health services and resources. When collaborating with trusted community organizations, KIs perceived that the SYCT program overcame barriers such as mistrust of government intervention and desire for privacy and motivated community members to utilize this resource to protect themselves against COVID-19.

The Implementation Experience of COVID-19 Rapid Antigen Testing in a Large-Scale Construction Project in Victoria, Australia

The coronavirus (COVID-19) pandemic has caused major disruptions to industries and workplaces. Rapid Antigen Tests (RATs) for COVID-19, which allow individuals to self-administer tests and receive timely results without laboratory testing, provide the opportunity for surveillance testing of asymptomatic individuals in non-medical settings. However, the literature offers few lessons regarding how to create enabling conditions for effective and sustainable implementation in a workplace setting. Guided by the RE-AIM framework, we assessed factors associated with the adoption, implementation, and maintenance of mandatory RAT in a large-scale construction project in Victoria, Australia. We used a mixed methods approach involving site observation, worker surveys (n = 30), and interviews with 51 site workers and managers to understand the implementation experience. Factors which facilitated adoption included easy, non-invasive testing procedure; sense of workplace safety; and strong backing by management and acceptance by workers that RATs helped limit COVID-19-related lost days of work. Gaps in knowledge and adherence to testing protocols, logistical challenges (test kit supply, observation of test results), and low appetite for long-term, mandatory testing emerged as challenges for effective implementation and sustainability. As RAT becomes normalized in a range of workplace settings, strategies will be required to support the sustainability of implementation, including longer-term acceptability of surveillance testing and adherence to testing protocols.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43477-023-00085-4.

Cost-effectiveness analysis of COVID-19 screening strategy under China's dynamic zero-case policy

This study aims to optimize the COVID-19 screening strategies under China's dynamic zero-case policy through cost-effectiveness analysis. A total of 9 screening strategies with different screening frequencies and combinations of detection methods were designed. A stochastic agent-based model was used to simulate the progress of the COVID-19 outbreak in scenario I (close contacts were promptly quarantined) and scenario II (close contacts were not promptly quarantined). The primary outcomes included the number of infections, number of close contacts, number of deaths, the duration of the epidemic, and duration of movement restriction. Net monetary benefit (NMB) and the incremental cost-benefit ratio were used to compare the cost-effectiveness of different screening strategies. The results indicated that under China's COVID-19 dynamic zero-case policy, high-frequency screening can help contain the spread of the epidemic, reduce the size and burden of the epidemic, and is cost-effective. Mass antigen testing is not cost-effective compared with mass nucleic acid testing in the same screening frequency. It would be more cost-effective to use AT as a supplemental screening tool when NAT capacity is insufficient or when outbreaks are spreading very rapidly.

Covid-19 Surveillance Testing and Resident Outcomes in Nursing Homes

BACKGROUND

Despite widespread adoption of surveillance testing for coronavirus disease 2019 (Covid-19) among staff members in skilled nursing facilities, evidence is limited regarding its relationship with outcomes among facility residents.

METHODS

Using data obtained from 2020 to 2022, we performed a retrospective cohort study of testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among staff members in 13,424 skilled nursing facilities during three pandemic periods: before vaccine approval, before the B.1.1.529 (omicron) variant wave, and during the omicron wave. We assessed staff testing volumes during weeks without Covid-19 cases relative to other skilled nursing facilities in the same county, along with Covid-19 cases and deaths among residents during potential outbreaks (defined as the occurrence of a case after 2 weeks with no cases). We reported adjusted differences in outcomes between high-testing facilities (90th percentile of test volume) and low-testing facilities (10th percentile). The two primary outcomes were the weekly cumulative number of Covid-19 cases and related deaths among residents during potential outbreaks.

RESULTS

During the overall study period, 519.7 cases of Covid-19 per 100 potential outbreaks were reported among residents of high-testing facilities as compared with 591.2 cases among residents of low-testing facilities (adjusted difference, -71.5; 95% confidence interval [CI], -91.3 to -51.6). During the same period, 42.7 deaths per 100 potential outbreaks occurred in high-testing facilities as compared with 49.8 deaths in low-testing facilities (adjusted difference, -7.1; 95% CI, -11.0 to -3.2). Before vaccine availability, high- and low-testing facilities had 759.9 cases and 1060.2 cases, respectively, per 100 potential outbreaks (adjusted difference, -300.3; 95% CI, -377.1 to -223.5), along with 125.2 and 166.8 deaths (adjusted difference, -41.6; 95% CI, -57.8 to -25.5). Before the omicron wave, the numbers of cases and deaths were similar in high- and low-testing facilities; during the omicron wave, high-testing facilities had fewer cases among residents, but deaths were similar in the two groups.

CONCLUSIONS

Greater surveillance testing of staff members at skilled nursing facilities was associated with clinically meaningful reductions in Covid-19 cases and deaths among residents, particularly before vaccine availability.

Economic evaluation of strategies against coronavirus: a systematic review

BACKGROUND

The COVID-19 outbreak was defined as a pandemic on 11 March 2020 by the World Health Organization. After that, COVID-19 has enormously influenced health systems around the world, and it has claimed more than 4.2 million deaths until July 2021. The pandemic has led to global health, social and economic costs. This situation has prompted a crucial search for beneficial interventions and treatments, but little is known about their monetary value. This study is aimed at systematically reviewing the articles conducted on the economic evaluation of preventive, control and treatment strategies against COVID-19.

MATERIAL AND METHOD

We searched PubMed, Web of Science, Scopus, and Google Scholar from December 2019 to October 2021 to find applicable literature to the economic evaluation of strategies against COVID-19. Two researchers screened potentially eligible titles and abstracts. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist was used to quality assessment of studies.

RESULTS

Thirty-six studies were included in this review, and the average CHEERS score was 72. Cost-effectiveness analysis was the most common type of economic evaluation, used in 21 studies. And the quality-adjusted life year (QALY) was the main outcome applied to measure the effectiveness of interventions, which was used in 19 studies. In addition, articles were reported a wide range of incremental cost-effectiveness ratio (ICER), and the lowest cost per QALY ($321.14) was related to the use of vaccines.

CONCLUSION

Based on the results of this systematic review, it seems that all strategies are likely to be more cost-effective against COVID-19 than no intervention and vaccination was the most cost-effective strategy. This research provides insight for decision makers in choosing optimal interventions against the next waves of the current pandemic and possible future pandemics.

Effectiveness of feedback control and the trade-off between death by COVID-19 and costs of countermeasures

We provided a framework of a mathematical epidemic modeling and a countermeasure against the novel coronavirus disease (COVID-19) under no vaccines and specific medicines. The fact that even asymptomatic cases are infectious plays an important role for disease transmission and control. Some patients recover without developing the disease; therefore, the actual number of infected persons is expected to be greater than the number of confirmed cases of infection. Our study distinguished between cases of confirmed infection and infected persons in public places to investigate the effect of isolation. An epidemic model was established by utilizing a modified extended Susceptible-Exposed-Infectious-Recovered model incorporating three types of infectious and isolated compartments, abbreviated as SEIIIHHHR. Assuming that the intensity of behavioral restrictions can be controlled and be divided into multiple levels, we proposed the feedback controller approach to implement behavioral restrictions based on the active number of hospitalized persons. Numerical simulations were conducted using different detection rates and symptomatic ratios of infected persons. We investigated the appropriate timing for changing the degree of behavioral restrictions and confirmed that early initiating behavioral restrictions is a reasonable measure to reduce the burden on the health care system. We also examined the trade-off between reducing the cumulative number of deaths by the COVID-19 and saving the cost to prevent the spread of the virus. We concluded that a bang-bang control of the behavioral restriction can reduce the socio-economic cost, while a control of the restrictions with multiple levels can reduce the cumulative number of deaths by infection.

Optimizing COVID-19 testing strategies on college campuses: evaluation of the health and economic costs

Colleges and universities in the US struggled to provide safe in-person education throughout the COVID-19 pandemic. Testing coupled with isolation is a nimble intervention strategy that can be tailored to mitigate health and economic costs, as the virus and our arsenal of medical countermeasures continue to evolve. We developed a decision-support tool to aid in the design of university-based testing strategies using a mathematical model of SARS-CoV-2 transmission. Applying this framework to a large public university reopening in the fall of 2021 with a 60% student vaccination rate, we find that the optimal strategy, in terms of health and economic costs, is twice weekly antigen testing of all students. This strategy provides a 95% guarantee that, throughout the fall semester, case counts would not exceed the CDC's original high transmission threshold of 100 cases per 100k persons over 7 days. As the virus and our medical armament continue to evolve, testing will remain a flexible tool for managing risks and keeping campuses open. We have implemented this model as an online tool to facilitate the design of testing strategies that adjust for COVID-19 conditions, university-specific parameters, and institutional goals.

Investigation of the diagnostic performance of the SARS-CoV-2 saliva antigen test: A meta-analysis

BACKGROUND

The COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Rapid identification and isolation of patients with COVID-19 are critical strategies to contain COVID-19. The saliva antigen test has the advantages of noninvasiveness and decreased transmission risk to health-care professionals. This meta-analysis investigated the diagnostic accuracy of the saliva antigen test for SARS-CoV-2.

METHODS

We searched for relevant studies in PubMed, Embase, Cochrane Library, and Biomed Central. Studies evaluating the diagnostic accuracy of saliva antigen tests for SARS-CoV-2 were included. The data of the included studies were used to construct a 2 × 2 table on a per patient basis. The overall sensitivity and specificity of saliva antigen tests were determined using a bivariate random-effects model.

RESULTS

Nine studies enrolling 9842 patients were included. The meta-analysis generated a pooled sensitivity of 65.3% and a pooled specificity of 99.7%. A subgroup analysis of the studies performing the chemiluminescent enzyme immunoassay (CLEIA) for participants from airports and public health centers revealed a pooled sensitivity of 93.6%.

CONCLUSION

Our findings demonstrated that the saliva antigen test performed using CLEIA exhibited higher sensitivity for the detection of SARS-CoV-2. Therefore, the saliva antigen test performed using CLEIA might be an effective and noninvasive screening tool for SARS-CoV-2.

Willingness to share contacts in case of COVID-19 positivity–predictors of collaboration resistance in a nation-wide Italian survey

Background

The unwillingness to share contacts is one of the least explored aspects of the COVID-19 pandemic. Here we report the factors associated with resistance to collaborate on contact tracing, based on the results of a nation-wide survey conducted in Italy in January-March 2021.

Methods and findings

The repeated cross-sectional on-line survey was conducted among 7,513 respondents (mean age 45.7, 50.4% women) selected to represent the Italian adult population 18–70 years old. Two groups were defined based on the direct question response expressing (1) unwillingness or (2) willingness to share the names of individuals with whom respondents had contact. We selected 70% of participants (training data set) to produce several multivariable binomial generalized linear models and estimated the proportion of variation explained by the model by McFadden R2, and the model’s discriminatory ability by the index of concordance. Then, we have validated the regression models using the remaining 30% of respondents (testing data set), and identified the best performing model by removing the variables based on their impact on the Akaike information criterion and then evaluating the model predictive accuracy. We also performed a sensitivity analysis using principal component analysis.

Overall, 5.5% of the respondents indicated that in case of positive SARS-CoV-2 test they would not share contacts. Of note, this percentage varied from 0.8% to 46.5% depending on the answers to other survey questions. From the 139 questions included in the multivariable analysis, the initial model proposed 20 independent factors that were reduced to the 6 factors with only modest changes in the model performance. The 6-variables model demonstrated good performance in the training (c-index 0.85 and McFadden R2 criteria 0.25) and in the testing data set (93.3% accuracy, AUC 0.78, sensitivity 30.4% and specificity 97.4%). The most influential factors related to unwillingness to share contacts were the lack of intention to perform the test in case of contact with a COVID-19 positive individual (OR 5.60, 95% CI 4.14 to 7.58, in a fully adjusted multivariable analysis), disagreement that the government should be allowed to force people into self-isolation (OR 1.79, 95% CI 1.12 to 2.84), disagreement with the national vaccination schedule (OR 2.63, 95% CI 1.86 to 3.69), not following to the preventive anti-COVID measures (OR 3.23, 95% CI 1.85 to 5.59), the absence of people in the immediate social environment who have been infected with COVID-19 (1.66, 95% CI 1.24 to 2.21), as well as difficulties in finding or understanding the information about the infection or related recommendations. A limitation of this study is the under-representation of persons not participating in internet-based surveys and some vulnerable groups like homeless people, persons with disabilities or migrants.

Conclusions

Our analysis revealed several groups that expressed unwillingness to collaborate on contact tracing. The identified patterns may play a principal role not only in the COVID-19 epidemic but also be important for possible future public health threats, and appropriate interventions for their correction should be developed and ready for the implementation.

Point of care molecular and antigen detection tests for COVID-19: current status and future prospects

INTRODUCTION

Detection of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has been critical to support and management of the COVID-19 pandemic. Point of care testing (POCT) for SARS-CoV-2 has been a widely used tool for detection of SARS-CoV-2.

AREAS COVERED

POCT nucleic acid amplification tests (NAATs) and rapid antigen tests (RATs) have been the most readily used POCT for SARS-CoV-2. Here, current knowledge on the utility of POCT NAATs and RATs for SARS-CoV-2 are reviewed and discussed alongside aspects of quality assurance factors that must be considered for successful and safe implementation of POCT.

EXPERT OPINION

Use cases for implementation of POCT must be evidence based, regardless of the test used. A quality assurance framework must be in place to ensure accuracy and safety of POCT.

Smart and connected devices in point-of-care molecular diagnostics: what role can they play in the response to COVID-19?

INTRODUCTION

Coronavirus disease-2019 (COVID-19) has been a huge public health challenge that has led to significant morbidity and mortality across the globe. Given the high prevalence and continued circulation of SARS-CoV-2 infection globally, accurate and rapid point-of-care testing is critical.

AREAS COVERED

Knowledge of role of digital technology including smart and connected devices in rapid diagnosis of COVID-19 is an evolving area of scientific investigation. This review discusses the importance of rapid at-home point-of-care testing, highlighting the possible role of smart and connected device-based molecular diagnostics for COVID-19.

EXPERT OPINION

Accurate and rapid diagnostic modalities have the potential to improve accessibility and efficiency of diagnosis of symptomatic and asymptomatic patients and could be instrumental in timely implementation of appropriate therapeutic interventions as well as public health measures to mitigate spread of infection. With emerging challenges like newer, virulent viral variants, global vaccine shortages and vaccine hesitancy, accurate diagnostic testing with the ability to rapidly identify infection remains critical and has the potential to be pivotal in pandemic control. Digital technologies are likely to become important tools in future of healthcare and technological advancements may play a crucial role in response to COVID-19 with the goal of ultimately overcoming this pandemic.

Impact of Fast SARS-CoV-2 Molecular Point-Of-Care Testing on Patients' Length of Stay in an Emergency Department

The ID NOW COVID-19 system (IDNOW) is a point-of-care test (POCT) providing results within 15 min. We evaluated the impact of IDNOW use on patient length of stay (LOS) in an emergency department (ED). In the ED of Saint-Louis Hospital, Paris, France, adult patients requiring a rapid diagnosis of SARS-CoV-2 were tested with Cepheid Xpert Xpress SARS-CoV-2 or FilmArray respiratory panel RP2 in the virology laboratory between 18 October and 3 November 2020 (period 1) and with IDNOW between 4 November and 30 November 2020 (period 2). A total of 676 patients participated in the study, 337 during period 1 and 339 during period 2. The median LOS in ED was significantly higher in period 1 than in period 2 (276 versus 208 min, P < 0.0001). More patients spent less than 4 h in the ED in period 2 (61.3%) than in period 1 (38.3%) (P < 0.0001). By univariate analysis, factors associated with ED LOS were hypertension, anosmia/ageusia, number of patients per day, and ID NOW implementation in period 2. By multivariate analysis, the period of testing remained significantly associated with ED LOS. Rapid molecular SARS-CoV-2 POCT was associated with a reduced LOS for patients admitted to an ED.

IMPORTANCE During COVID-19 pandemic upsurges, emergency departments had to deal with a massive flow of incoming patients. The need for COVID-19 infection status determination before medical ward admission worsened ED overcrowding. The development of molecular point-of-care testing gave new opportunities for getting faster results of SARS-CoV-2 genome detection 24 h a day. In our study, we show, with a multivariate analysis, that the use of the POCT COVID-19 IDNOW reduced the ED length of stay by 1 h. The rate of patients who waited less than 4 h in the ED increased significantly. Our study highlights the benefit of COVID-19 molecular POCT for preventing ED overcrowding and facilitating bed allocation and SARS-CoV-2-infected patient isolation.

Cost-effectiveness of interventions for the prevention and control of COVID-19: Systematic review of 85 modelling studies

Background

We aimed to quantitatively summarise the health economic evaluation evidence of prevention and control programs addressing COVID-19 globally.

Methods

We did a systematic review and meta-analysis to assess the economic and health benefit of interventions for COVID-19. We searched PubMed, Embase, Web of Science, and Cochrane Library of economic evaluation from December 31, 2019, to March 22, 2022, to identify relevant literature. Meta-analyses were done using random-effects models to estimate pooled incremental net benefit (INB). Heterogeneity was assessed using I2 statistics and publication bias was assessed by Egger's test. This study is registered with PROSPERO, CRD42021267475.

Results

Of 16 860 studies identified, 85 articles were included in the systematic review, and 25 articles (10 studies about non-pharmacological interventions (NPIs), five studies about vaccinations and 10 studies about treatments) were included in the meta-analysis. The pooled INB of NPIs, vaccinations, and treatments were $1378.10 (95% CI = $1079.62, $1676.59), $254.80 (95% CI = $169.84, $339.77) and $4115.11 (95% CI = $1631.09, $6599.14), respectively. Sensitivity analyses showed similar findings.

Conclusions

NPIs, vaccinations, and treatments are all cost-effective in combating the COVID-19 pandemic. However, evidence was mostly from high-income and middle-income countries. Further studies from lower-income countries are needed.

Rapid Antigen Assays for SARS-CoV-2: Promise and Peril

Though rapid antigen tests have historically problematic performance characteristics for the diagnosis of respiratory viral infections such as influenza, they have attained an unprecedented level of use in the context of the COVID-19 pandemic. Ease of use and scalability of rapid antigen tests has facilitated a democratization and scale of testing beyond anything reasonably achievable by traditional laboratory-based testing. In this chapter, we discuss the performance characteristics of rapid antigen testing for SARS-CoV-2 detection and their application to non-traditional uses beyond clinical diagnostic testing.

Willingness to pay for SARS-CoV-2 rapid antigen tests during the Covid-19 pandemic. Evidence from the general adult population

Objective

Our aim was to examine the willingness to pay (WTP) for SARS-CoV-2 rapid antigen tests and its correlates during the COVID-19 pandemic in Germany.

Study design/Methods

A representative online survey was conducted in late summer 2021 (with n = 3075; the average age was 44.5 years; 14.8 years ranging from 18 to 70 years) in Germany. Two-part models were conducted. Various correlates (such as empathy or altruism) were included in the regression analysis.

Results

The average WTP for SARS-CoV-2 rapid antigen tests (in euros) was 6.6 (standard deviation 8.4) in the general adult population. It markedly differed between subgroups (e.g. the average WTP was 2.9 among individuals not vaccinated against COVID-19 and 7.5 among individuals vaccinated against COVID-19; it was 5.4 among the lowest income decile, whereas it was 8.6 among the highest income decile). Regressions showed that a higher WTP for SARS-CoV-2 rapid antigen tests was associated with being male, being in the highest income group, being vaccinated against COVID-19, and having higher levels of empathy.

Conclusions

As the very first study in this area, our study described WTP for SARS-CoV-2 rapid antigen tests and some interesting differences between population subgroups. In particular, individuals not vaccinated against COVID-19 reported a low WTP for SARS-CoV-2 rapid antigen tests. Approximately one-fourth of the sample reported a WTP for SARS-CoV-2 rapid antigen tests of €0 among individuals vaccinated against COVID-19, whereas approximately two-thirds of those not vaccinated against COVID-19 reported such a WTP. Knowledge about the WTP for COVID-19 rapid antigen tests is important for policy makers (e.g. for testing strategies) during this pandemic. It may also give a rough estimation of the acceptance of such rapid tests.

Rapid antigen testing as a reactive response to surges in nosocomial SARS-CoV-2 outbreak risk

Healthcare facilities are vulnerable to SARS-CoV-2 introductions and subsequent nosocomial outbreaks. Antigen rapid diagnostic testing (Ag-RDT) is widely used for population screening, but its health and economic benefits as a reactive response to local surges in outbreak risk are unclear. We simulate SARS-CoV-2 transmission in a long-term care hospital with varying COVID-19 containment measures in place (social distancing, face masks, vaccination). Across scenarios, nosocomial incidence is reduced by up to 40-47% (range of means) with routine symptomatic RT-PCR testing, 59-63% with the addition of a timely round of Ag-RDT screening, and 69-75% with well-timed two-round screening. For the latter, a delay of 4-5 days between the two screening rounds is optimal for transmission prevention. Screening efficacy varies depending on test sensitivity, test type, subpopulations targeted, and community incidence. Efficiency, however, varies primarily depending on underlying outbreak risk, with health-economic benefits scaling by orders of magnitude depending on the COVID-19 containment measures in place.

Strategies to implement SARS-CoV-2 point-of-care testing into primary care settings: a qualitative secondary analysis guided by the Behaviour Change Wheel

BACKGROUND

The purpose of this study is to develop a theory-driven understanding of the barriers and facilitators underpinning physicians' attitudes and capabilities to implementing SARS-CoV-2 point-of-care (POC) testing into primary care practices.

METHODS

We used a secondary qualitative analysis approach to re-analyse data from a qualitative, interview study of 22 primary care physicians from 21 primary care practices across three regions in England. We followed the three-step method based on the Behaviour Change Wheel to identify the barriers to implementing SARS-CoV-2 POC testing and identified strategies to address these challenges.

RESULTS

Several factors underpinned primary care physicians' attitudes and capabilities to implement SARS-CoV-2 POC testing into practice. First, limited knowledge of the SARS-CoV-2 POC testing landscape and a demanding workload affected physicians' willingness to use the tests. Second, there was scepticism about the insufficient evidence pertaining to the clinical efficacy and utility of POC tests, which affected physicians' confidence in the accuracy of tests. Third, physicians would adopt POC tests if they were prescribed and recommended by authorities. Fourth, physicians required professional education and training to increase their confidence in using POC tests but also suggested that healthcare assistants should administer the tests. Fifth, physicians expressed concerns about their limited workload capacity and that extra resources are needed to accommodate any anticipated changes. Sixth, information sharing across practices shaped perceptions of POC tests and the quality of information influenced physician perceptions. Seventh, financial incentives could motivate physicians and were also needed to cover the associated costs of testing. Eighth, physicians were worried that society will view primary care as an alternative to community testing centres, which would change perceptions around their professional identity. Ninth, physicians' perception of assurance/risk influenced their willingness to use POC testing if it could help identify infectious individuals, but they were also concerned about the risk of occupational exposure and potentially losing staff members who would need to self-isolate.

CONCLUSIONS

Improving primary care physicians' knowledgebase of SARS-CoV-2 POC tests, introducing policies to embed testing into practice, and providing resources to meet the anticipated demands of testing are critical to implementing testing into practice.

Cost-Effectiveness of COVID-19 Policy Measures: A Systematic Review

OBJECTIVES

The COVID-19 pandemic has had a major impact on our society, with drastic policy restrictions being implemented to contain the spread of the severe acute respiratory syndrome coronavirus 2. This study aimed to provide an overview of the available evidence on the cost-effectiveness of various coronavirus disease 2019 policy measures.

METHODS

A systematic literature search was conducted in PubMed, Embase, and Web of Science. Health economic evaluations considering both costs and outcomes were included. Their quality was comprehensively assessed using the Consensus Health Economic Criteria checklist. Next, the quality of the epidemiological models was evaluated.

RESULTS

A total of 3688 articles were identified (March 2021), of which 23 were included. The studies were heterogeneous with regard to methodological quality, contextual factors, strategies' content, adopted perspective, applied models, and outcomes used. Overall, testing/screening, social distancing, personal protective equipment, quarantine/isolation, and hygienic measures were found to be cost-effective. Furthermore, the most optimal choice and combination of strategies depended on the reproduction number and context. With a rising reproduction number, extending the testing strategy and early implementation of combined multiple restriction measures are most efficient.

CONCLUSIONS

The quality assessment highlighted numerous flaws and limitations in the study approaches; hence, their results should be interpreted with caution because the specific context (country, target group, etc) is a key driver for cost-effectiveness. Finally, including a societal perspective in future evaluations is key because this pandemic has an indirect impact on the onset and treatment of other conditions and on our global economy.

Accuracy of saliva and nasopharyngeal sampling for detection of SARS-CoV-2 in community screening: a multicentric cohort study

Nasopharyngeal sampling for nucleic acid amplification testing (NAAT) is the standard diagnostic test of coronavirus disease 2019. Our objectives were to assess, in real-life conditions, the diagnostic accuracy of a nasopharyngeal point-of-care antigen (Ag) test and of saliva NAAT for detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in ambulatory care. This was a prospective cohort study from 19 October through 18 December 2020 in two community COVID-19 screening centers in Paris, France. Two nasopharyngeal swabs and one saliva sample were simultaneously collected. Diagnostic accuracies of nasopharyngeal Ag testing and of three saliva NAAT methods were assessed as compared to nasopharyngeal NAAT. A total of 1452 ambulatory children and adults were included. Overall, 129/1443 (9%) participants tested positive on nasopharyngeal NAAT (102/564 [18%] in symptomatic and 27/879 [3%] in asymptomatic participants). Sensitivity was 94%, 23%, 96%, and 94% for the three different protocols of saliva NAAT and for the nasopharyngeal Ag test, respectively. Estimates of specificity were above 95% for all methods. Diagnostic accuracy was similar in symptomatic and asymptomatic individuals. Diagnostic accuracy of nasopharyngeal Ag testing and of saliva NAAT is similar to that of nasopharyngeal NAAT, subject to compliance with specific protocols for saliva. Registration number: NCT04578509.

Evaluation of a saliva molecular point of care for the detection of SARS-CoV-2 in ambulatory care

Rapid identification of SARS-CoV-2-infected individuals is a cornerstone for the control of virus spread. The sensitivity of SARS-CoV-2 RNA detection by RT-PCR is similar in saliva and nasopharyngeal swabs. Rapid molecular point-of-care tests in saliva could facilitate, broaden and speed up the diagnosis. We conducted a prospective study in two community COVID-19 screening centers to evaluate the performances of a CE-marked RT-LAMP assay (EasyCoV) designed for the detection of SARS-CoV2 RNA from fresh saliva samples, compared to nasopharyngeal RT-PCR, to saliva RT-PCR and to nasopharyngeal antigen testing. Overall, 117 of the 1718 participants (7%) tested positive with nasopharyngeal RT-PCR. Compared to nasopharyngeal RT-PCR, the sensitivity and specificity of the RT-LAMP assay in saliva were 34% and 97%, respectively. The Ct values of nasopharyngeal RT-PCR were significantly lower in the 40 true positive subjects with saliva RT-LAMP (Ct 25.9) than in the 48 false negative subjects with saliva RT-LAMP (Ct 28.4) (p = 0.028). Considering six alternate criteria for reference tests, including saliva RT-PCR and nasopharyngeal antigen, the sensitivity of saliva RT-LAMP ranged between 27 and 44%. The detection of SARS-CoV-2 in crude saliva samples with an RT-LAMP assay had a lower sensitivity than nasopharyngeal RT-PCR, saliva RT-PCR and nasopharyngeal antigen testing.

Registration number: NCT04578509.

Time-course evaluation of the quantitative antigen test for severe acute respiratory syndrome coronavirus 2: The potential contribution to alleviating isolation of COVID-19 patients

Introduction

The automated quantitative antigen test (QAT), which detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is suitable for mass screening. However, its diagnostic capability differentiated by time from onset and potential contribution to infectivity assessment have not been fully investigated.

Methods

A retrospective, observational study using nasopharyngeal swab specimens from coronavirus disease (COVID-19) inpatients was conducted using Lumipulse^Ⓡ SARS-CoV-2 antigen test. Diagnostic accuracy was examined for the early (up to 10 days after onset) and late (over 10 days after onset) stages. Time-course QAT changes and reverse‐transcription quantitative polymerase chain reaction tests results were displayed as locally estimated scatterplot smoothing curve, and receiver operating characteristic curve (ROC) analysis was used to determine the appropriate cutoff value for differentiating the early and late stages.

Results

We obtained 100 specimens from 68 COVID-19 patients, including 51 early-stage and 49 late-stage specimens. QAT sensitivity and specificity were 0.82 (0.72–0.90) and 0.95 (0.75–0.99) for all periods, 0.93 (0.82–0.98) and 1.00 (0.39–1.00) for the early stage, and 0.66 (0.48–0.82) and 0.93 (0.69–0.99) for the late stage, respectively. The ROC analysis indicated an ideal cutoff value of 6.93 pg/mL for distinguishing early-from late-stage specimens. The sensitivity, specificity, positive predictive value, and negative predictive value for predicting the late stage were 0.76 (0.61–0.87), 0.76 (0.63–0.87), 0.76 (0.61–0.87), and 0.76 (0.63–0.87).

Conclusions

QAT has favorable diagnostic accuracy in the early COVID-19 stages. In addition, an appropriate cutoff point can potentially facilitate rapid identification of noncontagious patients.

SARS-CoV-2 testing strategies to contain school-associated transmission: model-based analysis of impact and cost of diagnostic testing, screening, and surveillance

Background

In March 2021, the Biden administration allocated $10 billion for COVID-19 testing in schools. We evaluate the costs and benefits of testing strategies to reduce the infection risks of full-time in-person K-8 education at different levels of community incidence.

Methods

We used an agent-based network model to simulate transmission in elementary and middle school communities, parameterized to a US school structure and assuming dominance of the delta COVID-19 variant. We assess the value of different strategies for testing students and faculty/staff, including expanded diagnostic testing ("test to stay" policies that take the place of isolation for symptomatic students or quarantine for exposed classrooms); screening (routinely testing asymptomatic individuals to identify infections and contain transmission); and surveillance (testing a random sample of students to signaling undetected transmission and trigger additional investigation or interventions).

Main outcome measures

We project 30-day cumulative incidence of SARS-CoV-2 infection; proportion of cases detected; proportion of planned and unplanned days out of school; and the cost of testing programs and of childcare costs associated with different strategies. For screening policies, we further estimate cost per SARS-CoV-2 infection averted in students and staff, and for surveillance, probability of correctly or falsely triggering an outbreak response at different incidence and attack rates.

Results

Accounting for programmatic and childcare costs, "test to stay" policies achieve similar model-projected transmission to quarantine policies, with reduced overall costs. Weekly universal screening prevents approximately 50% of in-school transmission, with a lower projected societal cost than hybrid or remote schooling. The cost per infection averted in students and staff by weekly screening is lower for older students and schools with higher mitigation and declines as community transmission rises. In settings where local student incidence is unknown or rapidly changing, surveillance may trigger detection of moderate-to-large in-school outbreaks with fewer resources compared to screening.

Conclusions

"Test to stay" policies and/or screening tests can facilitate consistent in-person school attendance with low transmission risk across a range of community incidence. Surveillance may be a useful reduced-cost option for detecting outbreaks and identifying school environments that may benefit from increased mitigation.