Drive-through testing for SARS-CoV-2 in symptomatic health and social care workers and household members: an observational cohort study

Analyzing factors affecting positivity in drive-through COVID-19 testing: a cross-sectional study

BACKGROUND

Demand for COVID-19 testing prompted the implementation of drive-through testing systems. However, limited research has examined factors influencing testing positivity in this setting.

METHODS

From October 2020 to March 2023, a total of 1,341 patients, along with their clinical information, were referred from local clinics to the Sasebo City COVID-19 drive-through PCR center for testing. Association between clinical information or factors related to the drive-through center and testing results was analyzed by Fisher's exact test and logistic regression models.

RESULTS

Individuals testing positive exhibited higher frequencies of upper respiratory symptoms; cough (OR 1.5 (95% CI 1.2-1.8), p < 0.001, q = 0.005), sore throat (OR 2.4 (95% CI 1.9-3.0), p < 0.001, q < 0.001), runny nose (OR 1.4 (95% CI 1.1-1.8), p = 0.002, q = 0.009), and systemic symptoms; fever (OR 1.5 (95% CI 1.1-2.0), p = 0.006, q = 0.02), headache (OR 1.9 (95% CI 1.4-2.5), p < 0.001, q < 0.001), and joint pain (OR 2.7 (95% CI 1.8-4.1), p < 0.001, q < 0.001). Conversely, gastrointestinal symptoms; diarrhea (OR 0.2 (95% CI 0.1-0.4), p < 0.001, q < 0.001) and nausea (OR 0.3 (95% CI 0.1-0.6), p < 0.001, q < 0.001) were less prevalent among positives. During omicron strain predominant period, higher testing positivity rate (OR 20 (95% CI 13-31), p < 0.001) and shorter period from symptom onset to testing (3.2 vs. 6.0 days, p < 0.001) were observed compared to pre-omicron period. Besides symptoms, contact history with infected persons at home (OR 4.5 (95% CI 3.1-6.5), p < 0.001, q < 0.001) and in office or school (OR 2.9 (95% CI 2.1-4.1), p < 0.001, q < 0.001), as well as the number of sample collection experiences by collectors (B 7.2 (95% CI 2.8-12), p = 0.002) were also associated with testing results.

CONCLUSIONS

These findings underscore the importance of factors related to drive-through centers, especially contact history interviews and sample collection skills, for achieving higher rates of COVID-19 testing positivity. They also contribute to enhanced preparedness for next infectious disease pandemics.

To PCR or not? The impact of shifting policy from PCR to rapid antigen tests to diagnose COVID-19 during the omicron epidemic: a nationwide surveillance study

Background

Coronavirus disease 2019 (COVID-19) had caused huge impacts worldwide. Polymerase chain reaction (PCR) is the mainstay diagnostic modality. In most hospitals in Taiwan, samples for PCR are collected at emergency department (ER) or outdoor clinics to avoid virus spread inside hospitals. Home rapid antigen test (RAT) is a feasible, low-cost, and convenient tool with moderate sensitivity and high specificity, which can be performed at home to reduce hospital visits. Due to comparably low severity of omicron variant and high vaccine coverage (~80% residents fully vaccinated with AstraZeneca, Moderna, or Pfizer BioNTech COVID-19 vaccines as of March 2022), the policy was shifted from containment to co-existing with COVID-19 in Taiwan. Virus spread rapidly in the community after the ease of social restrictive measurements. To acquire a confirmed diagnosis, PCR testing was requested for people with suspected COVID-19 infection. As a consequence, people with respiratory symptoms or contact history surged into hospitals for PCR testing, thus, the medical capacity was challenged. The diagnostic policy was altered from PCR to RAT, but the impact of diagnostic policy change remains unclear.

Objectives

We conducted this study to investigate the number of COVID-19 cases, PCR testing, hospitalizations, mortalities, and hospital visits during the epidemic and evaluate the impact of diagnostic policy change on hospital visits.

Methods

The diagnostic policy change was implemented in late May 2022. We used nationwide and hospital-based data of COVID-19 cases, PCR testing, hospitalizations, mortalities, and hospital visits before and after policy change as of 31 Jul 2022.

Results

During the omicron epidemic, significant and synchronous increase of COVID-19 patients, PCR testing, hospital visits were observed. COVID-19 cases increased exponentially since April 2022 and the COVID-19 patients peaked in June (1,943, 55,571, and 61,511 average daily new cases in April, May, and June, respectively). The PCR testing peaked in May (85,788 daily tests) with high positive rate (81%). The policy of RAT as confirmatory diagnosis was implemented on 26 May 2022 and a substantial decline of PCR testing numbers occurred (85,788 and 83,113 daily tests in May and June). People hospitalized for COVID-19 peaked in June (821.8 patients per day) and decreased in July (549.5 patients). The mortality cases also peaked in June (147 cases/day). This trend was also validated by the hospital-based data with a significant decrease of emergency department visits (11,397 visits in May while 8,126 visits in June) and PCR testing (21,314 in May and 6,158 in June). The proportion of people purely for PCR testing also decreased (10-26 vs. 5-14%, before and after policy change, respectively).

Conclusions

The impact of diagnostic policy change was a complicated issue and our study demonstrated the huge impact of diagnostic policy on health seeking behavior. The PCR testing numbers and emergency department visits had substantial decrease after diagnostic policy change, and the plateau of epidemic peak eased gradually in ~1 month later. Widespread RAT application may contribute to the decreased hospital visits and preserve medical capacity. Our study provides some evidences for policy maker's reference.

The critical role of engineering in the rapid development of COVID-19 diagnostics: Lessons from the RADx Tech Test Verification Core

Engineering plays a critical role in the development of medical devices, and this has been magnified since 2020 as severe acute respiratory syndrome coronavirus 2 swept over the globe. In response to the coronavirus disease 2019, the National Institutes of Health launched the Rapid Acceleration of Diagnostics (RADx) initiative to help meet the testing needs of the United States and effectively manage the pandemic. As the Engineering and Human Factors team for the RADx Tech Test Verification Core, we directly assessed more than 30 technologies that ultimately contributed to an increase of the country's total testing capacity by 1.7 billion tests to date. In this review, we present central lessons learned from this "apples-to-apples" comparison of novel, rapidly developed diagnostic devices. Overall, the evaluation framework and lessons learned presented in this review may serve as a blueprint for engineers developing point-of-care diagnostics, leaving us better prepared to respond to the next global public health crisis rapidly and effectively.

Wang Y, Ortlund E, Sullivan J, Rebolledo PA, Clavería V, Roback JD, Benoit M, Stone C, Esper A, Frank F, Lam WA. Don't forget about human factors: Lessons learned from COVID-19 point-of-care testing

During the COVID-19 pandemic, the development of point-of-care (POC) diagnostic testing accelerated in an unparalleled fashion. As a result, there has been an increased need for accurate, robust, and easy-to-use POC testing in a variety of non-traditional settings (i.e., pharmacies, drive-thru sites, schools). While stakeholders often express the desire for POC technologies that are "as simple as digital pregnancy tests," there is little discussion of what this means in regards to device design, development, and assessment. The design of POC technologies and systems should take into account the capabilities and limitations of the users and their environments. Such "human factors" are important tenets that can help technology developers create POC technologies that are effective for end-users in a multitude of settings. Here, we review the core principles of human factors and discuss lessons learned during the evaluation process of SARS-CoV-2 POC testing.

Protecting Nursing Homes and Long-Term Care Facilities From COVID-19: A Rapid Review of International Evidence

OBJECTIVES

The COVID-19 pandemic has highlighted the extreme vulnerability of older people and other individuals who reside in long-term care, creating an urgent need for evidence-based policy that can adequately protect these community members. This study aimed to provide synthesized evidence to support policy decision making.

DESIGN

Rapid narrative review investigating strategies that have prevented or mitigated SARS-CoV-2 transmission in long-term care.

SETTING AND PARTICIPANTS

Residents and staff in care settings such as nursing homes and long-term care facilities.

METHODS

PubMed/Medline, Cochrane Library, and Scopus were systematically searched, with studies describing potentially effective strategies included. Studies were excluded if they did not report empirical evidence (eg, commentaries and consensus guidelines). Study quality was appraised on the basis of study design; data were extracted from published reports and synthesized narratively using tabulated data extracts and summary tables.

RESULTS

Searches yielded 713 articles; 80 papers describing 77 studies were included. Most studies were observational, with no randomized controlled trials identified. Intervention studies provided strong support for widespread surveillance, early identification and response, and rigorous infection prevention and control measures. Symptom- or temperature-based screening and single point-prevalence testing were found to be ineffective, and serial universal testing of residents and staff was considered crucial. Attention to ventilation and environmental management, digital health applications, and acute sector support were also considered beneficial although evidence for effectiveness was lacking. In observational studies, staff represented substantial transmission risk and workforce management strategies were important components of pandemic response. Higher-performing facilities with less crowding and higher nurse staffing ratios had reduced transmission rates. Outbreak investigations suggested that facility-level leadership, intersectoral collaboration, and policy that facilitated access to critical resources were all significant enablers of success.

CONCLUSIONS AND IMPLICATIONS

High-quality evidence of effectiveness in protecting LTCFs from COVID-19 was limited at the time of this study, though it continues to emerge. Despite widespread COVID-19 vaccination programs in many countries, continuing prevention and mitigation measures may be required to protect vulnerable long-term care residents from COVID-19 and other infectious diseases. This rapid review summarizes current evidence regarding strategies that may be effective.

The association between SARS-CoV-2 RT-PCR cycle threshold and mortality in a community cohort

A coronavirus disease 2019 (COVID-19) diagnosis is widely made by the use of reverse transcription polymerase chain reaction (RT-PCR) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). When using RT-PCR, the infectivity of SARS-CoV-2 can be inferred from the threshold cycle (Ct) value [1]. It is best practice to confirm the validity of the standard curve using reference materials or in-house plasmid controls with known viral copy numbers [2]. As the Ct value represents the cycle number at which the signal breaches the threshold for positivity, a lower Ct value is indicative of a higher viral load. Although some studies suggest that viral load is associated with mortality and infectiousness [3, 4], a systematic review has identified little difference in viral load between pre-symptomatic, asymptomatic and symptomatic patients [5]. As a result, the clinical relevance of viral load remains controversial, and it is not used in clinical practice [6]. Here, we report the relationship between the Ct value and all-cause mortality for people who tested positive for SARS-CoV-2 on a combined nasal and pharyngeal swab in the Tayside region of Scotland, UK. This is a community cohort study and includes the local population of the region, as well as symptomatic health and social care workers tested as part of a screening programme [7]. In order to obtain clinical characteristics and outcomes for those who tested positive, anonymised record linkage was conducted between routine healthcare datasets as described previously [8]. All positive PCR tests from 12 March until 1 May, 2020 were included, and all deaths recorded by National Records Scotland until 20 May, 2020. Approval for anonymised data linkage was granted by the local Data Protection Officer (Caldicott Guardian).

Ct values from RT-PCR tests are associated with risk of mortality in SARS-CoV-2 infection. Hazards of Ct values <20 compared to >30 were 2.20 (95% CI 1.28–3.76) in a model adjusted for age, sex, comorbidities and hospitalisation.https://bit.ly/3gjuqdU

The protective effect of SARS-CoV-2 antibodies in Scottish healthcare workers

Background

Healthcare workers (HCWs) are believed to be at increased risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. It is not known to what extent the natural production of antibodies to SARS-CoV-2 is protective against re-infection.

Methods

A prospective observational study of HCWs in Scotland (UK) from May to September 2020 was performed. The Siemens SARS-CoV-2 total antibody assay was used to establish seroprevalence in this cohort. Controls, matched for age and sex to the general local population, were studied for comparison. New infections (up to 2 December 2020) post antibody testing were recorded to determine whether the presence of SARS-CoV-2 antibodies protects against re-infection.

Results

A total of 2063 health and social care workers were recruited for this study. At enrolment, 300 HCWs had a positive antibody test (14.5%). 11 out of 231 control sera tested positive (4.8%). HCWs therefore had an increased likelihood of a positive test (OR 3.4, 95% CI 1.85–6.16; p<0.0001). Dentists were most likely to test positive. 97.3% of patients who had previously tested positive for SARS-CoV-2 by reverse transcriptase (RT)-PCR had positive antibodies. 18.7% had an asymptomatic infection. There were 38 new infections with SARS-CoV-2 in HCWs who were previously antibody negative, and one symptomatic RT-PCR-positive re-infection. The presence of antibodies was therefore associated with an 85% reduced risk of re-infection with SARS-CoV-2 (hazard ratio 0.15, 95% CI 0.06–0.35; p=0.026).

Conclusion

HCWs were three times more likely to test positive for SARS-CoV-2 than the general population. Almost all infected individuals developed an antibody response, which was 85% effective in protecting against re-infection with SARS-CoV-2.

In this study, healthcare workers were three times more likely to test positive for #SARSCoV2 than the general population. Almost all infected individuals developed an antibody response, and this was 85% effective in protecting against re-infection.https://bit.ly/3mLPUmk

What do we know about SARS-CoV-2 transmission? A systematic review and meta-analysis of the secondary attack rate and associated risk factors

INTRODUCTION

Current SARS-CoV-2 containment measures rely on controlling viral transmission. Effective prioritization can be determined by understanding SARS-CoV-2 transmission dynamics. We conducted a systematic review and meta-analyses of the secondary attack rate (SAR) in household and healthcare settings. We also examined whether household transmission differed by symptom status of index case, adult and children, and relationship to index case.

METHODS

We searched PubMed, medRxiv, and bioRxiv databases between January 1 and July 25, 2020. High-quality studies presenting original data for calculating point estimates and 95% confidence intervals (CI) were included. Random effects models were constructed to pool SAR in household and healthcare settings. Publication bias was assessed by funnel plots and Egger's meta-regression test.

RESULTS

43 studies met the inclusion criteria for household SAR, 18 for healthcare SAR, and 17 for other settings. The pooled household SAR was 18.1% (95% CI: 15.7%, 20.6%), with significant heterogeneity across studies ranging from 3.9% to 54.9%. SAR of symptomatic index cases was higher than asymptomatic cases (RR: 3.23; 95% CI: 1.46, 7.14). Adults showed higher susceptibility to infection than children (RR: 1.71; 95% CI: 1.35, 2.17). Spouses of index cases were more likely to be infected compared to other household contacts (RR: 2.39; 95% CI: 1.79, 3.19). In healthcare settings, SAR was estimated at 0.7% (95% CI: 0.4%, 1.0%).

DISCUSSION

While aggressive contact tracing strategies may be appropriate early in an outbreak, as it progresses, measures should transition to account for setting-specific transmission risk. Quarantine may need to cover entire communities while tracing shifts to identifying transmission hotspots and vulnerable populations. Where possible, confirmed cases should be isolated away from the household.

What do we know about SARS-CoV-2 transmission? A systematic review and meta-analysis of the secondary attack rate and associated risk factors

INTRODUCTION

Current SARS-CoV-2 containment measures rely on controlling viral transmission. Effective prioritization can be determined by understanding SARS-CoV-2 transmission dynamics. We conducted a systematic review and meta-analyses of the secondary attack rate (SAR) in household and healthcare settings. We also examined whether household transmission differed by symptom status of index case, adult and children, and relationship to index case.

METHODS

We searched PubMed, medRxiv, and bioRxiv databases between January 1 and July 25, 2020. High-quality studies presenting original data for calculating point estimates and 95% confidence intervals (CI) were included. Random effects models were constructed to pool SAR in household and healthcare settings. Publication bias was assessed by funnel plots and Egger's meta-regression test.

RESULTS

43 studies met the inclusion criteria for household SAR, 18 for healthcare SAR, and 17 for other settings. The pooled household SAR was 18.1% (95% CI: 15.7%, 20.6%), with significant heterogeneity across studies ranging from 3.9% to 54.9%. SAR of symptomatic index cases was higher than asymptomatic cases (RR: 3.23; 95% CI: 1.46, 7.14). Adults showed higher susceptibility to infection than children (RR: 1.71; 95% CI: 1.35, 2.17). Spouses of index cases were more likely to be infected compared to other household contacts (RR: 2.39; 95% CI: 1.79, 3.19). In healthcare settings, SAR was estimated at 0.7% (95% CI: 0.4%, 1.0%).

DISCUSSION

While aggressive contact tracing strategies may be appropriate early in an outbreak, as it progresses, measures should transition to account for setting-specific transmission risk. Quarantine may need to cover entire communities while tracing shifts to identifying transmission hotspots and vulnerable populations. Where possible, confirmed cases should be isolated away from the household.

Characteristics and outcomes of health and social care workers testing positive for SARS-CoV-2 in the Tayside region of Scotland

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and reported outcomes among health and social care workers (HSCWs) is concerning [1–3]. Early in the outbreak it was recommended in the UK that HSCWs experiencing symptoms of a cough or fever remain absent from work for 7 days. In order to address this problem, National Health Service (NHS) Tayside, a health board in Scotland covering a population of 400,000, was the first in Scotland to set up a drive-through testing programme for HSCWs, other key workers and their symptomatic household contacts (including children), with results available within 24 h, allowing staff to return to work following a negative test [4]. As testing for SARS-CoV-2 was limited to hospitalised patients across much of Europe there is limited data on the self-reported clinical characteristics and outcomes of patients in the community with coronavirus disease 2019 (COVID-19). Here, we report characteristics and outcomes of HSCWs presenting to the drive-through testing centre who tested positive for SARS-CoV-2 on a combined nasal and pharyngeal swab. Anonymised record linkage was conducted between routinely collected healthcare datasets in order to ascertain clinical characteristics and outcomes of those who tested positive. All hospitalisations until 25 April and deaths until 20 May, 2020 were recorded. Approval was obtained from the local data protection officer (Caldicott Guardian).

Tayside, Scotland was one of the first health boards to institute testing for all symptomatic workers. As expected, there was a high prevalence of SARS-CoV-2 among health and social care workers; however, in most cases disease was mild. https://bit.ly/38JaUmB

Drive-through testing for SARS-CoV-2 in symptomatic health and social care workers and household members: an observational cohort study

The requirement for health and social care workers to self-isolate when they or their household contacts develop symptoms consistent with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to critical staff shortages in the context of a pandemic. In this report, we describe the implementation of a drive-through testing service in a single National Health Service region in Scotland. From 17 March 2020 to 11 April 2020, 1890 SARS-CoV-2 reverse transcription PCR assay (RT-PCR) tests were performed. 22% of tests were positive. Allowing the remaining 78% of staff to return to work within 24 hours was estimated to save over 8000 working days during the peak pandemic period.