IMPORTANCEThere is an urgent need to assess the feasibility of COVID-19 surveillance measures in educational settings. OBJECTIVETo assess whether young children can feasibly self-collect SARS-CoV-2 samples for surveillance testing over the course of an academic year.

Background In order to mitigate the spread of SARS-CoV-2 and the COVID-19 pandemic, public health officials have recommended self-isolation, self-quarantine of exposed household contacts (HHC), and mask use to limit viral spread within households and communities. While household transmission of SARS-CoV-2 is common, risk factors for HHC transmission are poorly understood. Methods In this prospective cohort study, we enrolled 37 households with at least one reverse transcription polymerase chain reaction-confirmed (RT-PCR) COVID-19 index case from March 2020 - March 2021, in order to calculate secondary attack rates (SAR) and define risk factors for secondary infections. Participants were tested daily for SARS-CoV-2 via RT-PCR, using self-collected lower nasal samples. Households were followed until all members tested negative for seven consecutive days. We collected demographics, medical conditions, relationship to index case, and socioeconomic indicators. Subgroup data analysis was conducted and stratified by positivity status. Results Of 99 enrolled participants, 37 were index cases and 62 were household contacts (HHC), of whom 25 HHC were infected (40.3%). Secondary attack rate (SAR) was highest among adults caring for a parent (n=4/4, 100%) and parents of index cases (5/10, 50%). Households whose income came from service work had greater risk of transmission compared to households whose primary income was technology (n=5/7; 71.4% vs 3/8; 37.5% respectively). Pediatric contacts were at lower risk of infection when compared to adult contacts (n=5/18, 27.8% vs n=20/44, 45.5% respectively). Conclusion This study suggests that household transmission represents a key source of community-based infection of SARS-CoV-2. Allocating resources for education/training regarding prevention among infected individuals and their close contacts will be critical for control of future outbreaks of SARS-CoV-2. Disclosures All Authors: No reported disclosures

Background Serological tests directed against SARS-CoV-2 can provide information about the timing of infection and immunity against the virus. However, the kinetics of the host immune response to SARS-CoV-2 remain poorly understood. We established a household transmission study to analyze the serological responses within households, to determine longitudinal immune responses to infection. Methods From April 2020 to April 2022, we prospectively enrolled 76 households with at least one RT-PCR confirmed case of COVID-19. Participants were asked to provide blood samples at three time points: at baseline within 2 weeks of the index’s diagnosis of COVID-19, and at one- and three-months post-enrollment. Samples were tested for the presence of IgG antibodies against SARS-CoV-2 spike protein via an FDA EUA approved ELISA. Demographics, medical history, and symptomatology were also collected. Results To date, we have analyzed 238 serologic samples from 135 participants, including 82 baseline samples, 89 one-month samples, and 67 three-month samples. At baseline, 67.8% (n=40/59) of all confirmed cases tested positive for SARS-CoV-2 antibodies, which increased to 86.4% (n=57/66) at the one month, and 85.1% at three months (n=40/47). Of those confirmed infected participants that failed to seroconvert at baseline, almost all reported symptoms (n=14/19, 73.7%) and did not have chronic medical conditions (n=17/19, 89.5%). Of the 19, 3 failed to seroconvert by their third visit. All individuals who were fully vaccinated at the time of each visit tested positive for antibodies at baseline (n=26), one-month (n=27), and three-months (n=20). Of those who were not fully vaccinated, 56 (41.1%) were positive for antibodies at baseline, 62 (59.7%) were positive at one -month, and 47 (63.8%) at three-months. Differences in seropositivity rates between pediatric and adult participants, as well as between index cases and household contacts, at each visit were also identified (Table 1). Conclusion Identifying differences in seroprevalence in various demographic groups can provide insight into longitudinal immune responses post-infection. Future analyses on seropositivity among previously infected individuals who received therapeutics may be of interest. Disclosures Andra L. Blomkalns, MD, MBA, Eli Lilly and Company: Grant/Research Support Yvonne A. Maldonado, MD, Pfizer: Grant/Research Support|Pfizer: Member, DSMB, Pfizer Meningococcal Vaccine clinical trial.

Background While pediatric cases of COVID-19 are at low risk for adverse events, schoolchildren should be considered for surveillance as they can become infected at school and serve as sources of household or community transmission. Our team assessed the feasibility of young children self-collecting SARS-CoV-2 samples for surveillance testing in an educational setting. Methods Students at a K-8 school were tested weekly for SARS-CoV-2 from September 2020 - June 2021. Error rates were collected from September 2020 - January 2021. Clinical staff provided all students with instructions for anterior nares specimen self-collection and then observed them to ensure proper technique. Instructions included holding the sterile swab while making sure not to touch the tip, inserting the swab into their nostril until they start to feel resistance, and rubbing the swab in four circles before repeating the process in their other nostril. An independent observer timed random sample self-collections from April - June 2021. Results 2,590 samples were collected from 209 students during the study period when data on error rates were collected. Errors occurred in 3.3% of all student encounters (n=87). Error rates over time are shown in Figure 1, with the highest rate occurring on the first day of testing (n=20/197, 10.2%) and the lowest in January 2021 (n=1/202, 0.5%). 2,574 visits for sample self-collection occurred during the study period when independent timing data was collected (April - June 2021). Of those visits, 7.5% (n=193) were timed. The average duration of each visit was 70 seconds. Figure 1. Swab Error Rates Over Time Conclusion Pediatric self-collected lower nasal swabs are a viable and easily tolerated specimen collection method for SARS-CoV-2 surveillance in school settings, as evidenced by the low error rate and short time window of sample self-collection during testing. School administrators should expect errors to drop quickly after implementing testing. Disclosures All Authors: No reported disclosures