Pediatric SARS-CoV-2 Seroprevalence in Arkansas Over the First Year of the COVID-19 Pandemic

Younger and rural children are more likely to be hospitalized for SARS-CoV-2 infections

PURPOSE

To identify characteristics of SARS-CoV-2 infection that are associated with hospitalization in children initially evaluated in a Pediatric Emergency Department (ED).

METHODS

We identified cases of SARS-CoV-2 positive patients seen in the Arkansas Children's Hospital (ACH) ED or hospitalized between May 27, 2020, and April 28, 2022, using ICD-10 codes within the Pediatric Hospital Information System (PHIS) Database. We compared infection waves for differences in patient characteristics and used logistic regressions to examine which features led to a higher chance of hospitalization.

FINDINGS

We included 681 pre-Delta cases, 673 Delta cases, and 970 Omicron cases. Almost 17% of patients were admitted to the hospital. Compared to Omicron-infected children, pre-Delta and Delta-infected children were twice as likely hospitalized (OR = 2.2 and 2.0, respectively; p<0.0001). Infants under one year were >3 times as likely to be hospitalized than children ages 5-14 years regardless of wave (OR = 3.42; 95%CI = 2.36-4.94). Rural children were almost three times as likely than urban children to be hospitalized across all waves (OR = 2.73; 95%CI = 1.97-3.78). Finally, those with a complex condition had nearly a 15-fold increase in odds of admission (OR = 14.6; 95%CI = 10.6-20.0).

CONCLUSIONS

Children diagnosed during the pre-Delta or Delta waves were more likely to be hospitalized than those diagnosed during the Omicron wave. Younger and rural patients were more likely to be hospitalized regardless of the wave. We suspect lower vaccination rates and larger distances from medical care influenced higher hospitalization rates.

Seroprevalence of SARS-CoV-2 antibodies among children receiving primary care in Toronto, Ontario

OBJECTIVE

Characterizing the seroprevalence of SARS-CoV-2 antibodies in children is needed to optimize the COVID-19 public health response. We quantified the seroprevalence of SARS-CoV-2 infection-acquired antibodies and vaccine-acquired antibodies among children receiving primary care in Toronto, Canada.

METHODS

We conducted a longitudinal cohort study between January 2021 and November 2022 in healthy children aged 0-16 years receiving primary care in Toronto. The primary and secondary outcomes were seroprevalence of SARS-COV-2 infection-acquired antibodies and vaccine-acquired antibodies ascertained from finger-prick dried blood spots. Samples were tested using an enzyme-linked immunosorbent assay for antibodies to full-length spike trimer and nucleocapsid. We explored sociodemographic differences with Firth's penalized generalized estimating equations.

RESULTS

Of the 475 participants, 50.1% were girls and mean age was 6.4 years (SD = 3.2). We identified 103 children seropositive for infection-acquired antibodies, with a crude seroprevalence that rose from 2.6% (95%CI 1.39-4.92) from January to July 2021 to 50.7% (95%CI 39.5-61.8) by July to November 2022. Seroprevalence of vaccine-acquired antibodies was 45.2% by July to November 2022 (95%CI 34.3-56.58). No differences in sociodemographic factors (age, sex, income, or ethnicity) were identified for infection-acquired antibodies; however, children with vaccine-acquired antibodies were more likely to be older, have mothers with university education, and have mothers who had also been vaccinated.

CONCLUSION

Our results provide a benchmark for seroprevalence of SARS-CoV-2 antibodies in children in Toronto. Ongoing monitoring of the serological status of children is important, particularly with the emergence of new variants of concern, low vaccine coverage, and discontinuation of PCR testing.

Factors associated with SARS-CoV-2 infection in unvaccinated children and young adults

BACKGROUND AND OBJECTIVES

Pediatric COVID-19 cases are often mild or asymptomatic, which has complicated estimations of disease burden using existing testing practices. We aimed to determine the age-specific population seropositivity and risk factors of SARS-CoV-2 seropositivity among children and young adults during the pandemic in British Columbia (BC).

METHODS

We conducted two cross-sectional serosurveys: phase 1 enrolled children and adults < 25 years between November 2020-May 2021 and phase 2 enrolled children < 10 years between June 2021-May 2022 in BC. Participants completed electronic surveys and self-collected finger-prick dried blood spot (DBS) samples. Samples were tested for immunoglobulin G antibodies against ancestral spike protein (S). Descriptive statistics from survey data were reported and two multivariable analyses were conducted to evaluate factors associated with seropositivity.

RESULTS

A total of 2864 participants were enrolled, of which 95/2167 (4.4%) participants were S-seropositive in phase 1 across all ages, and 61/697 (8.8%) unvaccinated children aged under ten years were S-seropositive in phase 2. Overall, South Asian participants had a higher seropositivity than other ethnicities (13.5% vs. 5.2%). Of 156 seropositive participants in both phases, 120 had no prior positive SARS-CoV-2 test. Young infants and young adults had the highest reported seropositivity rates (7.0% and 7.2% respectively vs. 3.0-5.6% across other age groups).

CONCLUSIONS

SARS-CoV-2 seropositivity among unvaccinated children and young adults was low in May 2022, and South Asians were disproportionately infected. This work demonstrates the need for improved diagnostics and reporting strategies that account for age-specific differences in pandemic dynamics and acceptability of testing mechanisms.

SARS-CoV-2 serology in pediatrics: Seroprevalence studies in unvaccinated children and humoral antibody response post vaccination

BACKGROUND

Humoral response against SARS-CoV-2 is increasingly accepted as the central correlate of immune protection. Recent pediatric seroprevalence data are extremely limited. Significant knowledge gaps also exist in immune response to mRNA SARS-CoV-2 vaccination in children. As children demonstrate distinct response to naïve infection relative to adults, it is essential to investigate age-specific differences in seroprevalence and antibody response to SARS-CoV-2 vaccination.

METHODS

Seroprevalence was assessed through two cross-sectional serosurveys prior to COVID-19 vaccination approval in children <5 years using residual patient specimens (n = 2902). To assess antibody response post-vaccination, 842 participants (580 children, 262 adults) were prospectively recruited with informed consent. Participation required completion of a health questionnaire and blood donation. Samples were collected at varying times post-vaccination and assayed using the Abbott AdviseDx SARS-CoV-2 IgG II and DiaSorin LIAISON SARS-CoV-2 TrimericS IgG assays.

RESULTS

Significant increases in seroprevalence were observed between the first and second serosurveys in unvaccinated children <6 months to 5 years (38-75%). In the prospective vaccination cohort, serokinetic response decreased with time post-dose of an mRNA vaccine. Measured IgG titres were significantly higher in children relative to adults across all time points.

CONCLUSIONS

This is the largest evaluation of quantitative SARS-CoV-2 antibody assays in a cohort of Canadian children, adolescents, and adults. Findings suggest high rates of SARS-CoV-2 exposure among unvaccinated young children in the Toronto community. Additional data supports children have higher antibody titres relative to adults post-vaccination.

A longitudinal study of SARS-CoV-2 antibody seroprevalence and mitigation behaviors among college students at an Arkansas University

Objective: Assess university students' SARS-CoV-2 antibody seroprevalence and mitigation behaviors over time. Participants: Randomly selected college students (N = 344) in a predominantly rural Southern state. Methods: Participants provided blood samples and completed self-administered questionnaires at three timepoints over the academic year. Adjusted odds ratios and 95% confidence intervals were estimated from logistic regression analyses. Results: SARS-CoV-2 antibody seroprevalence was 18.2% in September 2020, 13.1% in December, and 45.5% in March 2021 (21% for those with no vaccination history). SARS-CoV-2 antibody seroprevalence was associated with large social gatherings, staying local during the summer break, symptoms of fatigue or rhinitis, Greek affiliation, attending Greek events, employment, and using social media as the primary COVID-19 information source. In March 2021, seroprevalence was associated with receiving at least one dose of a COVID-19 vaccination. Conclusion: SARS-CoV-2 seroprevalence was higher in this population of college students than previous studies. Results can assist leaders in making informed decisions as new variants threaten college campuses.

Rural Research Network to engage rural and minority community members in translational research

Background

To address the high prevalence of health disparities and lack of research opportunities among rural and minority communities, the University of Arkansas for Medical Sciences (UAMS) developed the Rural Research Network in January 2020.

Aim

The aim of this report is to describe our process and progress in developing a rural research network. The Rural Research Network provides a platform to expand research participation opportunities to rural Arkansans, many of whom are older adults, low-income individuals, and underrepresented minority populations.

Methods

The Rural Research Network leverages existing UAMS Regional Programs family medicine residency clinics within an academic medical center.

Results

Since the inception of the Rural Research Network, research infrastructure and processes have been built within the regional sites. Twelve diverse studies have been implemented with recruitment and data collection from 9248 participants, and 32 manuscripts have been published with residents and faculty from the regional sites. Most studies were able to recruit Black/African American participants at or above a representative sample.

Conclusions

As the Rural Research Network matures, the types of research will expand in parallel with the health priorities of Arkansas.

Relevance to Patients

The Rural Research Network demonstrates how Cancer Institutes and sites funded by a Clinical and Translational Science Award can collaborate to expand research capacity and increase opportunities for research among rural and minority communities.

Younger and Rural Children are More Likely to be Hospitalized for SARS-CoV-2 Infections

Purpose

To identify characteristics of SARS-CoV-2 infection that are associated with hospitalization in children initially evaluated in a Pediatric Emergency Department (ED).

Methods

We identified cases of SARS-CoV-2 positive patients seen in the Arkansas Children's Hospital (ACH) ED or hospitalized between May 27, 2020, and April 28, 2022 using ICD-10 codes within the Pediatric Hospital Information System (PHIS) Database. We compared infection waves for differences in patient characteristics, and used logistic regressions to examine which characteristics led to a higher chance of hospitalization.

Findings

We included 681 pre-Delta cases, 673 Delta cases, and 970 Omicron cases. Almost 17% of patients were admitted to the hospital. Compared to Omicron infected children, pre-Delta and Delta infected children were twice as likely to be hospitalized (OR=2.2 and 2.0, respectively; p<0.0001). Infants less than 1 year of age were >3 times as likely to be hospitalized than children ages 5-14 years regardless of wave (OR=3.42; 95%CI=2.36-4.94). Rural children were almost 3 times as likely than urban children to be hospitalized across all waves (OR=2.73; 95%CI=1.97-3.78). Finally, those with a complex condition had nearly a 15-fold increase in odds of admission (OR=14.6; 95%CI=10.6-20.0).

Conclusions

Children diagnosed during the pre-Delta or Delta waves were more likely to be hospitalized than those diagnosed during the Omicron wave. Younger and rural patients were more likely to be hospitalized regardless of wave. We suspect lower vaccination rates and larger distances from medical care influenced higher hospitalization rates.

Comparison of the prevalence of SARS-CoV-2 nucleoprotein antibodies in healthcare workers and an unselected adult and paediatric all-comer patient population: insights from a longitudinal study of healthcare workers and concurrent serial cross-sectional studies of patients at an academic medical centre in Austria

OBJECTIVES

This study aimed to estimate and compare the prevalence of the virus-specific antibodies against the SARS-CoV-2 nucleoprotein antigen (anti-SARS-CoV-2 N) in healthcare workers and an all-comer paediatric and adult patient population.

DESIGN, SETTING AND PARTICIPANTS

A longitudinal study enrolling healthcare professionals and concurrent serial cross-sectional studies of unselected all-comer patients were conducted at an Austrian academic medical centre. Healthcare workers were tested at enrolment and after 1, 2, 3, 6 and 12 months. The cross-sectional studies in patients were conducted at three time periods, which roughly coincided with the times after the first, second and third wave of SARS-CoV-2 in Austria (ie, 24 August-7 September 2020; 8-22 February 2021 and 9-23 November 2021). Anti-SARS-CoV-2 N antibodies were measured using a sandwich electrochemiluminescence assay (Roche).

RESULTS

In total, 2735 and 9275 samples were measured in 812 healthcare workers (median age: 40 years, 78% female) and 8451 patients (median age: 55 years, 52% female), respectively. Over the entire study period, anti-SARS-CoV-2 N antibodies were detected in 98 of 812 healthcare workers, resulting in a seroprevalence of 12.1% (95% CI 10.0% to 14.5%), which did not differ significantly (p=0.63) from that of the all-comer patient population at the end of the study period (407/3184; 12.8%, 95% CI 11.7% to 14.0%). The seroprevalence between healthcare workers and patients did not differ significantly at any time and was 1.5-fold to 2-fold higher than the number of confirmed cases in Austria throughout the pandemic. In particular, there was no significant difference in the seroprevalence between paediatric and adult patients at any of the tested time periods.

CONCLUSION

Throughout the pandemic, healthcare staff and an adult and paediatric all-comer patient population had similar exposure to SARS-CoV-2.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT04407429.

Infection-induced immunity is associated with protection against SARS-CoV-2 infection, but not decreased infectivity during household transmission

Background

Understanding the impact of infection-induced immunity on SARS-CoV-2 transmission will provide insight into the transition of SARS-CoV-2 to endemicity. Here we estimate the effects of prior infection induced immunity and children on SARS-CoV-2 transmission in households.

Methods

We conducted a household cohort study between March 2020-June 2022 in Managua, Nicaragua where when one household member tests positive for SARS-CoV-2, household members are closely monitored for SARS-CoV-2 infection. Using a pairwise survival model, we estimate the association of infection period, age, symptoms, and infection-induced immunity with secondary attack risk.

Results

Overall transmission occurred in 72.4% of households, 42% of household contacts were infected and the secondary attack risk was 13.0% (95% CI: 11.7, 14.6). Prior immunity did not impact the probability of transmitting SARS-CoV-2. However, participants with pre-existing infection-induced immunity were half as likely to be infected compared to naïve individuals (RR 0.53, 95% CI: 0.39, 0.72), but this reduction was not observed in children. Likewise, symptomatic infected individuals were more likely to transmit (RR 24.4, 95% CI: 7.8, 76.1); however, symptom presentation was not associated with infectivity of young children. Young children were less likely to transmit SARS-CoV-2 than adults. During the omicron era, infection-induced immunity remained protective against infection.

Conclusions

Infection-induced immunity is associated with protection against infection for adults and adolescents. While young children are less infectious, prior infection and asymptomatic presentation did not reduce their infectivity as was seen in adults. As SARS-CoV-2 transitions to endemicity, children may become more important in transmission dynamics.

Article summary

Infection-induced immunity protects against SARS-CoV-2 infection for adolescents and adults; however, there was no protection in children. Prior immunity in an infected individual did not impact the probability they will spread SARS-CoV-2 in a household setting.

Cross-sectional seroprevalence surveys of SARS-CoV-2 antibodies in children in Germany, June 2020 to May 2021

The rate of SARS-CoV-2 infections in children remains unclear due to many asymptomatic cases. We present a study of cross-sectional seroprevalence surveys of anti-SARS-CoV-2 IgG in 10,358 children recruited in paediatric hospitals across Germany from June 2020 to May 2021. Seropositivity increased from 2.0% (95% CI 1.6, 2.5) to 10.8% (95% CI 8.7, 12.9) in March 2021 with little change up to May 2021. Rates increased by migrant background (2.8%, 4.4% and 7.8% for no, one and two parents born outside Germany). Children under three were initially 3.6 (95% CI 2.3, 5.7) times more likely to be seropositive with levels equalising later. The ratio of seropositive cases per recalled infection decreased from 8.6 to 2.8. Since seropositivity exceeds the rate of recalled infections considerably, serologic testing may provide a more valid estimate of infections, which is required to assess both the spread and the risk for severe outcomes of SARS-CoV-2 infections.

Children are less likely to be infected with SARS-CoV-2 and develop less severe disease than adults, which makes estimation of infection rates challenging. Here, the authors conduct seroprevalence surveys of children in Germany, describe changes in prevalence over time, and identify risk factors for infection.

Seroprevalence of SARS‐CoV‐2 antibodies in front‐line pediatric health care workers

Objective

The goal of this study was to determine the prevalence of SARS‐CoV‐2 infections in pediatric front‐line health care workers (HCWs) using SARS‐CoV‐2 serum antibodies as an indicator of infection.

Methods

In this cross‐sectional study, we collected blood samples and survey responses from HCWs in a 38‐bed pediatric emergency department. Serum antibodies to SARS‐CoV‐2 (IgM and/or IgG) were measured using a 2‐step enzyme‐linked immunosorbent assay (ELISA) to detect antibodies against the Spike protein receptor binding domain (RBD), the ectodomain of Spike (S), and the nucleoprotein (N).

Results

We collected survey responses and serum samples from 54 pediatric front‐line HCWs from October 2020 through April 2021. Among the 29 unvaccinated HCWs, 4 (13.7%) had antibodies to SARS‐CoV‐2. For the 25 vaccinated HCWs, 10 (40%) were seropositive; 3 were <10 days from the first vaccine dose and 7 were ≥10 days after the first dose. Two of the 10 seropositive vaccines had a prior positive reverse transcription polymerase chain reaction test. Individuals ≥10 days from receiving the first vaccine dose were 37.5 (95% CI: 3.5–399.3) times more likely to have SARS‐CoV‐2 antibodies than unvaccinated individuals or those <10 days from first vaccine dose.

Conclusions

Evidence of widespread SARS‐CoV‐2 infections was not found in unvaccinated front‐line HCWs from a pediatric ED as of April 2021. Future work will be required to determine the reasons underlying the lower SARS‐CoV‐2 antibody prevalence compared to adult HCWs.

Temporal Variations in Seroprevalence of Severe Acute Respiratory Syndrome Coronavirus 2 Infections by Race and Ethnicity in Arkansas

Background

The aim of this study was to estimate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates in the small rural state of Arkansas, using SARS-CoV-2 antibody prevalence as an indicator of infection.

Methods

We collected residual serum samples from adult outpatients seen at hospitals or clinics in Arkansas for non-coronavirus disease 2019 (COVID-19)-related reasons. A total of 5804 samples were identified over 3 time periods: 15 August-5 September 2020 (time period 1), 12 September-24 October 2020 (time period 2), and 7 November-19 December 2020 (time period 3).

Results

The age-, sex-, race-, and ethnicity-standardized SARS-CoV-2 seroprevalence during each period, from 2.6% in time period 1 to 4.1% in time period 2 and 7.4% in time period 3. No statistically significant difference in seroprevalence was found based on age, sex, or residence (urban vs rural). However, we found higher seroprevalence rates in each time period for Hispanics (17.6%, 20.6%, and 23.4%, respectively) and non-Hispanic Blacks (4.8%, 5.4%, and 8.9%, respectively) relative to non-Hispanic Whites (1.1%, 2.6%, and 5.5%, respectively).

Conclusions

Our data imply that the number of Arkansas residents infected with SARS-CoV-2 rose steadily from 2.6% in August to 7.4% in December 2020. There was no statistical difference in seroprevalence between rural and urban locales. Hispanics and Blacks had higher rates of SARS-CoV-2 antibodies than Whites, indicating that SARS-CoV-2 spread disproportionately in racial and ethnic minorities during the first year of the COVID-19 pandemic.