key: cord-0689832-fpo1wag2
authors: Roarty, Cathal; Tonry, Claire; McFetridge, Lisa; Mitchell, Hannah; Watson, Chris; Waterfield, Thomas
title: Kinetics and seroprevalence of SARS-CoV-2 antibodies in children
date: 2020-11-19
journal: Lancet Infect Dis
DOI: 10.1016/s1473-3099(20)30884-7
sha: 0e3771fabbbf47a18ca3a2aa847b2168d01fc4ec
doc_id: 689832
cord_uid: fpo1wag2

nan

To the best of our knowledge, no longitudinal study has reported the kinetics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses in children. Here we report the results of the second round of antibody testing in children from a prospective multicentre cohort study in the UK. The protocol and initial results are available elsewhere. 1,2 Recruitment took place between April 16, and July 3, 2020, at five UK sites (Belfast, Cardiff, Glasgow, London, and Manchester) and included healthy children aged 2-15 years. Follow-up visits at all five UK sites took place between June 26, and Aug 15, 2020.

Of the 992 participants in the first round, 849 (86%) returned. Seroprevalence was measured with the Elecsys Anti-SARS-CoV-2 Total Antibody assay (Roche, Basel, Switzerland) and the LIAISON SARS-CoV-2 S1/S2 IgG assay (DiaSorin, Saluggia, Italy). The median time between initial and follow-up visits was 62 days (IQR 52-70; range 43-81). 65 (7·66%, 95% CI 6·05-9·64) of 849 tests were reactive based on the manufacturers' suggested cutoffs. This proportion was not substantially different to the seroprevalence (6·9% 95% CI 5·4 to 8·6; 68 of 992) reported during recruitment. The median age of participants with reactive antibody tests during the second round was 10 years (IQR 7-14; range 3-16). As with the baseline results, there was variation in seroprevalence between sites (appendix p 3).

45 participants with reactive antibody tests in the first round who attended the follow-up visit had reactive antibody tests in the second round. In these individuals, we observed increases in antibody titres from the first round to the second round with both assays: with Roche's Elecsys assay, mean antibody titres increased from 84·7 cutoff index (COI) to 115·8 COI (difference 31·08, 95% CI 13·82-48·34, p=0·0007), and with DiaSorin's LIAISON assay, mean antibody titres increased from 67·5 AU/mL to 81·4 AU/mL (13·89, 0·31-27·46; p=0·0452).

These results indicate that antibody titres in children exposed to SARS-CoV-2 remain at a detectable level for at least 62 days, and that in this cohort mean antibody titres increased over time. This finding is consistent with available data on antibody titres in adults. 3, 4 TW reports grants from Public Health Agency during the conduct of the study. All other authors declare no competing interests. 

Seroprevalence of SARS-CoV-2 antibodies in children: a prospective multicentre cohort study

Seroprevalence of SARS-CoV-2 antibodies in children of healthcare workers-a prospective multicentre cohort study protocol

Humoral immune response to SARS-CoV-2 in Iceland

Robust neutralizing antibodies to SARS-CoV-2 infection persist for months

See Online for appendix Lancet Infect Dis