key: cord-0910778-ch80rvyw authors: Ford, James S.; Chua, Evan C.; Sandhu, Charankyla K.; Morris, Beth; May, Larissa S; Cohen, Stuart H.; Holmes, James F. title: Use of an Asymptomatic COVID-19 Testing Protocol in a Pediatric Emergency Department date: 2022-02-07 journal: J Emerg Med DOI: 10.1016/j.jemermed.2022.01.015 sha: 0674fffa1aa776ac1f47fd63953a52ea5750d881 doc_id: 910778 cord_uid: ch80rvyw Background : High rates of asymptomatic infections with Coronavirus of 2019 (COVID-19) have been reported. Objectives : We aimed to describe an asymptomatic COVID-19 testing protocol in a pediatric emergency department (ED). Methods : This was a retrospective cohort study of pediatric patients (<18 years) who were tested for COVID-19 via the asymptomatic testing protocol at a single urban pediatric ED between May 2020 and January 2021. This included all pediatric patients undergoing admission, urgent procedures and psychiatric facility placement. The primary outcome was the percentage of positive COVID-19 tests. COVID-19 testing was performed via real-time polymerase chain reaction ribonucleic acid assay testing. County-level COVID-19 data was used to estimate local daily COVID-19 cases/100,000 individuals (from all ages). Data were described with simple descriptive statistics. Results : 1,459 children were tested for COVID-19 under the asymptomatic protocol. The mean age was 8.2 ± 5.8 years. Two tests were inconclusive and 29 (2.0%, 95% CI 1.3, 2.8%) were positive. Of the 29 positive cases, 14 (48%, 95% CI 29-67%) had abnormal vital signs or signs and symptoms of COVID-19 on retrospective review. A total of 15 truly asymptomatic infections were identified. On the days that asymptomatic cases were identified, the lowest average daily community rate was 7.67 cases/100,000 individuals. Conclusions : Asymptomatic COVID-19 positivity rates in the pediatric ED were low when the average daily community rate was less than 7.5 cases/100,000 individuals. In the current pandemic, ED clinicians should assess for signs and symptoms of COVID-19, even when children present to the ED with unrelated chief complaints. As of January 2022, over 293 million cases of Coronavirus Disease of 2019 (COVID-19) have been reported globally, with children comprising an estimated 13% of all cases, in some regions [1, 2] . Diagnosis of COVID-19 in children is notoriously difficult, owing to the heterogeneous symptomatology elicited by the virus in this population [3] . The rate of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in all patients is estimated to be between 1.6-56.5% [4] [5] [6] . Asymptomatic carriage may be more common in high-endemicity regions [5, 7] . Asymptomatic transmission is thought to be an important mechanism of viral dissemination, as there often exists a delay in SARS-CoV-2 polymerase chain reaction (PCR) ribonucleic acid (RNA) positivity and symptom onset, with one study suggesting that 44% of new cases occur following exposure to an asymptomatic individual [8, 9] . The infection reproductive number, R 0 , which represents the average number of new individuals an infected individual will in turn infect, was estimated at 2.2-2.7 during the early COVID-19 pandemic [10, 11] . However, SARS-CoV-2 asymptomatic spread has been implicated in why R 0 estimates from the early pandemic did not sufficiently explain the rampant spread of the virus; new studies indicate that the R 0 may be twice as high as initially predicted (R 0 =5.7, 95% CI 3.8-8.9) [12] . With an R 0 of 5.7, the threshold for "herd immunity" is >82% of the population [12] . As of January 2022, only 62.3% of the United States (U.S.) population had been fully vaccinated [13] . Even with an aggressive U.S. national vaccination campaign, it may be several months before this goal is realized [14] . In the interim, continued epidemiological surveillance will be essential to identifying asymptomatic infections and controlling the spread of the virus. Children may be important vectors of asymptomatic disease due to the logistical difficulties of mask-wearing in younger children, as well as a perceived lower risk of transmission [15] . As such, identifying asymptomatic children represents a key opportunity to control the spread of the virus. With many ambulatory care settings being temporally closed, or having moved to telemedicine visits, the Emergency Department (ED) has become integral in the delivery of COVID-19-related care in many communities. Previous studies have found that between 4-28% of pediatric patients with documented Sars-CoV-2 infections were asymptomatic [3, [16] [17] [18] [19] . However, few studies report rates of SARS-CoV-2 positivity in an asymptomatic pediatric population [6] . In the present study, we aimed to describe screening for COVID-19 in asymptomatic pediatric patients in the ED, and sought to describe the clinical characteristics of positive cases who were identified via asymptomatic testing. This was a retrospective cohort study of data from the (blinded) health system's electronic health record. This study was approved by the study site's institutional review board. The study site is an urban, level 1 trauma center and tertiary referral center with an annual pediatric ED volume of 16,000 patients. The study site resides in a county with a population of 1,527,718 people. We included all pediatric (less than 18 years of age) ED patients who had a COVID-19 test ordered under the site's asymptomatic screening protocol, either in the ED or within 24 hours of admission from the ED. Data was collected from May 1, 2020 to January 31, 2021. The asymptomatic testing protocol was established due to concerns that SARS-CoV-2 infections would be difficult to control in the close living environments of psychiatric hospitals, and the study site wanted to ensure patients did not have COVID-19 prior to transfer to these facilities. The program was later expanded to include testing for all patients admitted to the hospital from the ED, all patients awaiting placement in other close living environments (i.e. skilled nursing facility, jail or other congregate living facility and patients undergoing procedures. All patients undergoing asymptomatic testing were required to wear surgical masks, and all ED providers were also required to wear surgical masks. At the time of test ordering, the provider was required to enter the indication for asymptomatic testing, including "other." Test samples were obtained by nasopharyngeal swabbing, and samples underwent detection of SARS-CoV-2 using a reverse transcriptase polymerase chain reaction assay. Two assays were used during the study period including a high-throughput platform (Cobas 6800, Roche Diagnostics, Pleasanton, CA) and a medium-throughput platform (BDMax, Becton Dickinson, Franklin Lakes, NJ). Both assays were sanctioned by the Food and Drug Administration's Emergency Use Authorization, and validated for use with nasopharyngeal swab samples. For each patient meeting eligibility criteria, the following data were explicitly defined and collected from the electronic health record: age, sex, Emergency Severity Index (ESI) triage criteria, triage vital signs, indication for asymptomatic COVID-19 testing, COVID-19 test result, and admission team. ESI is a triage scheme that stratifies patients into five categories from one (most severe) to five (least severe) [20] . Data on history of sick contacts or recent COVID-19 exposure were not available. The primary outcome measure was COVID-19 test result (positive or negative). In patients with positive test results, clinical data were abstracted. These data included signs or retrospective studies where appropriate [22] . Any patients found to have any signs or symptoms of COVID-19 upon retrospective analysis, were later reclassified as symptomatic. Additionally, since abnormal vital signs (ie hypoxia, tachycardia, fever etc) could be plausibly related to an occult COVID-19 infection, patients with abnormal vital signs were also retrospectively reclassified as symptomatic. Tachycardia was defined by age as follows: 0 to 1 years, greater than 160 beats per minute (bpm); 1 to 6 years, greater than 130 bpm; 7 to 12 years, greater than 110 bpm; over 12 years, greater than 100 bpm. Fever was defined as an initial temperature greater than 38.0°C. Tachypnea was defined by age as follows: 0 to 1 year, greater than 50 breaths/minute; 1 to 12 years of age, greater than 30 breaths/minute; over 12 years, greater than 25 breaths/minute [23] . Hypoxia was defined as an oxygen saturation less than 92%. Signs and symptoms of possible COVID-19 infection included any of the following: fever (subjective or objective), chills, cough, shortness of breath, fatigue, myalgias, headache, loss of taste/smell, sore throat, nasal congestion, runny nose or diarrhea [21] . (Blinded) County COVID-19 data were collected from the (blinded) County Public Health Epidemiology COVID-19 Dashboards. Daily COVID-19 rates were calculated by taking the number of positive daily cases divided by the estimated (blinded) County population as of January 1, 2020 (n=1,555,365) [24, 25] . The community COVID-19 rate was calculated as a seven-day daily average (Sunday-Saturday). A daily average was necessary as COVID-19 testing availability varied by day of the week. As many (blinded) County COVID-19 testing locations were closed on Saturday and Sunday, testing on these dates were much lower on weekends compared to weekdays. To account for this variation in testing frequency, a seven-day average was calculated to provide a more accurate representation of COVID-19 positivity in the community. Data regarding the county of residence for individual patients were not available. Data Analysis: Data were described with simple descriptive statistics. Continuous data were described with the mean ± one standard deviation. Ninety-five percent confidence intervals (95% CI) were presented where appropriate. Data analysis was conducted with Stata 15 (StataCorp. 2017, College Station, TX). A total of 1,459 pediatric ED patients were tested for COVID-19 under the asymptomatic testing protocol. The mean age of patients was 8.2 ± 5.8 years and 56% (n=820) of patients were male. The most common indication for asymptomatic testing was hospital admission (70%, n=1,011). Table 1. A total of 29 (2.0%, 95% CI 1.3, 2.8%) patients tested positive for COVID-19. Two patients had inconclusive test results. Patient sex and age were similar between those who tested positive for COVID-19 and those who tested negative. Of the 29 positive cases, 14 (48%, 95% CI 29-67%) cases had signs or symptoms of COVID-19, abnormal vital signs, and/or altered mental status indicating that the patient was not truly asymptomatic. One patient was on total parental nutrition and thus potentially immunocompromised, otherwise no patient was considered high risk for COVID-19. SARS-CoV-2 S1/S2 IgG antibody testing was negative in the single patient who was tested. In COVID-19 positive children who were found to be symptomatic on retrospective analysis, chest radiography was performed in eleven (38% of all positives, 95% CI 21, 58) patients and was abnormal in four (14%, 95% CI 4, 32) patients. Findings on chest radiography included small airway disease, consolidation/opacity, pleural effusion, and ground glass attenuation. The Pediatric Infectious Diseases service was consulted in a single patient admitted for wound care. This patient subsequently required supplemental oxygen and was treated with IVIG and steroids (solumedrol followed by a prednisone taper) during hospitalization for possible multisystem inflammatory syndrome in children (MIS-C). No patients in the asymptomatic testing protocol died. The weekly average community COVID-19 infection rate ranged from 0.4 to 57.3 cases per 100,000, with the largest spikes in positive cases occurring mid-June 2020 to September 2020, and between late November 2020 and early January 2021 (Figure 1) [24] . No asymptomatic positive cases occurred when the weekly average community rate was less than 7.67 cases/day/100,000 residents. As data continues to emerge on the asymptomatic transmissibility of SARS-CoV-2, the necessity of establishing testing protocols to identify these cases is paramount in preventing inpatient disease outbreaks. In this study, to our knowledge, we describe the largest cohort of asymptomatic pediatric COVID-19 testing in the emergency department. In one multicenter study, 3.7% (10/264) of asymptomatic patients who were tested for SARS-CoV-2 were positive [6] . In one large German study conducted during a similar time period to our study, COVID-19 positivity for all asymptomatic children who were admitted or underwent hospital procedures was 0.4% [26] . During our 9-month study period, 2% (29/1,459) of patients tested via the asymptomatic testing protocol were found to be positive, however, upon further review, only 1% (15/1,549) of patients were truly asymptomatic. However, since the asymptomatic protocol only tested children who were being admitted, undergoing an urgent procedure, or were being placed in another inpatient setting (i.e. psychiatric facility/detention facility), our positivity rate may not represent the asymptomatic rate of children from the surrounding community. The high rate of symptomatic/asymptomatic misclassification among COVID-19 positive patients highlights the difficulty in assessing symptomatology in pediatric populations. If these patients had not been tested, their infection status likely would have remained unknown, posing a nosocomial infection risk to healthcare staff and other patients. During the study period, there were two large spikes in case positivity in (blinded) County, which occurred between mid-June 2020 and late September 2020 (7-day rolling average positivity rage range: 5-8.4%) and between early November 2020 and late January 2021 (7-day rolling average positivity rate range: 5-11.9%) [27] . The magnitude of these spikes in SARS-CoV-2 test positivity were similar to those seen in the national data over the same time frames, suggesting that the study institution resided in a moderate-endemicity region, during the study period [28] . In our study, the majority of asymptomatic cases occurred during these local spikes in SARS-CoV-2 positivity, and no asymptomatic cases were identified when the case rate was less than 7.67/day/100,000 or when overall local test positivity was less than 3.3% [24, 27] . However, the local case rate was greater than 7.67/day/100,000 for the majority of our study, so low asymptomatic positivity during this time period may be due to sampling bias. These data suggest that the risk of asymptomatic infection appears correlated with local disease burden. It also may provide guidance for asymptomatic testing when testing resources are limited. The present study must be interpreted in the setting of its limitations. As this was a single-center study, our results may not be generalizable to other settings. Our study provides data from a moderate-endemicity region, so our data may not reflect the asymptomatic testing conditions of low or high-endemicity regions. This study was retrospective and is thus limited by the data available in the electronic medical record and subject to the limitations of a retrospective study. As the data were digitally abstracted from the EHR, we minimized errors in manual data abstraction. Thresholds for considering vital signs abnormal were liberal. Using more conservative vital sign thresholds would have increased the number of children with abnormal vital signs and likely decreased the total number of truly asymptomatic cases. While the overall prevalence of asymptomatic SARS-CoV-2 infections was low, an asymptomatic screening protocol detected unknown infections in patients including those who had been misclassified as asymptomatic by ED providers. The rate of asymptomatic SARS-CoV-2 infections may be correlated with local prevalence of disease. High rates of asymptomatic infections with Coronavirus of 2019 (COVID-19) have been reported, and asymptomatic transmission is thought to be an important mechanism of viral dissemination. This study attempts to demonstrate the utility of a COVID-19 asymptomatic screening protocol in a pediatric ED. Both truly asymptomatic and symptomatic patients thought to be asymptomatic were identified using the testing protocol. Asymptomatic testing protocols for patients with inpatient dispositions can help prevent placing infected patients in communal living spaces, potentially avoiding nosocomial transmission. Signs and/or Symptoms missed during initial evaluation in patients who were tested under the asymptomatic protocol but who were later reclassified as "symptomatic" Sign/Symptom Count 1 Fever 3 Tachycardia 7 Tachypnea 2 Cough 2 Fatigue 3 Diarrhea 3 Headache 4 Nasal Discharge 1 1 14 patients who were initially screened under the asymptomatic protocol were later found to have symptoms. 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