Emergence of SARS-CoV-2 Alpha (B.1.1.7) variant, infection rates, antibody seroconversion and seroprevalence rates in secondary school students and staff: Active prospective surveillance, December 2020 to March 2021, England

Shamez Ladhani ,Felicity Aiano ,Bernadette Brent ,Kevin E Brown ,Gayatri Amirthalingam ,Joanne Beckmann ,Maria Zambon ,Georgina Ireland ,Joanna Garstang ,Joanna Ellis ,John Poh ,Angie Lackenby ,Andrew Brent ,Meaghan Kall ,Zahin Amin-Chowdhury ,Lenesha Warrener ,Ezra Linley ,Frances Baawuah ,Ray Borrow ,Ifeanyichukwu Okike ,Shazaad Ahmad ,Mary Ramsay

doi:10.1016/j.jinf.2021.08.019

Abstract

ObjectivesWe assessed SARS-CoV-2 infection, seroprevalence and seroconversion in students and staff when secondary schools reopened in March 2021.MethodsWe initiated SARS-CoV-2 surveillance in 18 secondary schools across six regions in September 2020. Participants provided nasal swabs for RT-PCR and blood samples for SARS-CoV-2 antibodies at the beginning (September 2020) and end (December 2020) of the autumn term and at the start of the spring term (March 2021).FindingsIn March 2021, 1895 participants (1100 students:795 staff) were tested; 5.6% (61/1094) students and 4.4% (35/792) staff had laboratory-confirmed SARS-CoV-2 infection from December 2020-March 2021. Nucleoprotein-antibody seroprevalence was 36.3% (370/1018) in students and 31.9% (245/769) in staff, while spike-antibody prevalence was 39.5% (402/1018) and 59.8% (459/769), respectively, similar to regional community seroprevalence. Between December 2020 and March 2021, 14.8% (97/656; 95%CI: 12.2–17.7) students and 10.0% (59/590; 95%CI: 7.7–12.7) staff seroconverted. Weekly seroconversion rates were similar from September to December 2020 (8.0/1000) and from December 2020 to March 2021 (7.9/1000; students: 9.3/1,000; staff: 6.3/1,000).InterpretationBy March 2021, a third of secondary school students and staff had evidence of prior infection based on N-antibody seropositivity, and an additional third of staff had evidence of vaccine-induced immunity based on S-antibody seropositivity.

Highlights

In December 2020, we found similar antibody seroprevalence and seroconversion rates in staff and students, which were comparable to local community rates at the time.[11]
1895 participants were tested in Round 3, 1100 students and 795 staff (Table 1)
This was supported by similar S-antibody seropositivity of 39.5% in students who were unvaccinated at the time, but 59.8% of staff had detectable spike antibodies because two-thirds of the school staff had been vaccinated as part of the national COVID-19 vaccine rollout

Summary

Objectives

We assessed SARS-CoV-2 infection, seroprevalence and seroconversion in students and staff when secondary schools reopened in March 2021. Methods: We initiated SARS-CoV-2 surveillance in 18 secondary schools across six regions in September 2020. Nucleoprotein-antibody seroprevalence was 36.3% (370/1018) in students and 31.9% (245/769) in staff, while spike-antibody prevalence was 39.5% (402/1018) and 59.8% (459/769), respectively, similar to regional community seroprevalence. Between December 2020 and March 2021, 14.8% (97/656; 95%CI: 12.2– 17.7) students and 10.0% (59/590; 95%CI: 7.7–12.7) staff seroconverted. Seroconversion rates were similar from September to December 2020 (8.0/1000) and from December 2020 to March 2021 (7.9/1000; students: 9.3/1,000; staff: 6.3/1,000). Interpretation: By March 2021, a third of secondary school students and staff had evidence of prior infection based on N-antibody seropositivity, and an additional third of staff had evidence of vaccine-induced immunity based on S-antibody seropositivity

Methods

Results

Discussion

Conclusion