key: cord-0884919-f996lx3g
authors: Venkataraman, A.; S, B.; Putilibai, S.; S, L. R.; Amperayani, S.; S, S.; Manoharan, A.; Sophi, A.; R, A.; Sadasivam, K.; Goenka, A.; V, R. A.
title: Correlation of SARS-CoV-2 serology and clinical phenotype amongst hospitalised children in a tertiary children's hospital in India
date: 2021-02-01
journal: nan
DOI: 10.1101/2021.01.29.21250660
sha: 6dec4d37774d6585c30830846b20e06eeb0d0d72
doc_id: 884919
cord_uid: f996lx3g

Introduction: Children usually present with minimal or no symptoms of SARS-CoV-2 infection. Antibody responses to SARS-CoV-2 in children from low- and middle-income countries (LMIC) have not been well described. We describe the prevalence of anti SARS-CoV-2 antibodies and clinical phenotype of seropositive children admitted to a tertiary children's hospital in South India. Methods: To determine the seropositivity and describe the clinical characteristics of SARS-CoV-2 infection amongst hospitalised children, we performed a prospective clinical data collection and blood sampling of children admitted to Kanchi Kamakoti CHILDS Trust Hospital, Chennai, India over 4 months of the COVID-19 pandemic. In seropositive children, we compared antibody titres between children with and without PIMS-TS. Results: Of 463 children, 91 (19.6%) were seropositive. The median (range) age of seropositive children was 5 years (1 month - 17 years). Clinical presentation was consistent with Paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 infection (PIMS-TS) in 48% (44/91) of seropositive children. The median (range) antibody titre was 54.8 (11.1-170.9) AU/ml among all seropositive children. The median antibody titre among the children with PIMS-TS (60.3 AU/mL) was significantly (p=0.01) higher when compared to the children without PIM-TS (54.8 AU/mL). Conclusion: We describe the antibody responses to SARS-CoV-2 amongst hospitalised children in a LMIC tertiary children's hospital. Almost half of the seropositive children had PIMS-TS. Antibody levels may be helpful in the diagnosis and disease stratification of PIMS-TS.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection appears to be less severe in children compared with adults.[1-3] Determining the occurrence of SARS-CoV-2 infection in children is an essential facet of understanding the epidemiology of COVID-19 and the possible role of children in transmission. [4] [5] [6] [7] Data on SARS-CoV-2 seroprevalence in children has mostly been from developed countries, [5] [6] [7] [8] and there are almost no data from low-and middle-income countries (LMIC). We conducted a prospective serological survey to describe the frequency of anti-SARS-CoV-2 antibodies and the associated clinical phenotype in children presenting to a tertiary children's hospital in Chennai, India.

We conducted a prospective cross-sectional study of children older than 1 month admitted to Kanchi Kamakoti CHILDS Trust Hospital (KKCTH), a tertiary children's hospital in Chennai, India from 1 June 2020 to 30 September 2020 and report the symptomatology and clinical findings of infection. The study team approached caregivers of all children admitted to hospital for participation in the study. Demographic, epidemiological and medical data were collected on a standardised case report form. Blood was collected into EDTA tubes (BD Biosciences) and plasma obtained by centrifugation, and frozen at -80 0 C until use. Study staff involved in serological assays were blinded to clinical data.

Antibodies were quantified in plasma using iFlash® SARS-CoV-2 IgG and IgM chemiluminescence antibody assay (CLIA) (YHLO Biotechnology Corporation, Shenzhen, China) according to the is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint manufacturer's instructions. This is a quantitative CLIA for the detection of IgG and IgM against the SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in human serum/plasma, which has been approved by the Indian Council for Medical Research (ICMR) for SARS-CoV-2 IgG and IgM testing in India [9] . An antibody titre of ≥ 10 AU/ml was considered positive.

Acute COVID 19 and severity of COVID 19 was defined according to the the Ministry of Health and 

Informed consent was obtained from caregivers, and assent was obtained from children where appropriate. The study was approved by the KKCTH CHILDS Trust Medical Research Foundation ethics committee and was registered at Clinical Trials Registry India (CTRI/2020/09/028040).

Continuous variables are presented as medians and interquartile ranges (IQRs), and categorical variables are reported as numbers and proportions. Comparison between the groups was performed using the Mann-Whitney U test and p < 0.05 was considered statistically significant; all tests were two sided. All statistical analyses were performed using SPSS version 24. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint

Between June and September 2020, 1311 children were admitted to KKCTH. All the 1311 children were approached for participation, of which 843 were excluded; 102 were less than 1 month old and 741 declined participation. Of the 468 enrolled children, five were excluded due to insufficient blood sample and 463 were included in the final analysis ( Figure 1 ). Children were recruited from the inpatient wards (n=356, 77%), emergency room (n=71, 15%) and paediatric intensive care unit (n=36, 8%). The median age was 5 years old (range 1 month old -17 years old); and 57% (266/463) were male. SARS-CoV-2 real-time reverse transcriptase polymerase chain reaction (RT-PCR) was positive in 13% (62/463). Anti-SARS-CoV-2 IgG antibodies were detected in 91/463, giving a seropositivity rate of 19.6% (95% CI 15.4 to 22.5, n=463) and the median antibody titre was 54.8 AU/ml (range 11.09 -170.9). When seropositive children were stratified according to age, 12% (11/91) were under 1 year, 30% (27/11) were 1-5 years old, 46% (42/91) were 5-12 years old and 12% (11/91) were above 12 years old. We did not find any difference in the seropositivity between male and female [20% (54/266) vs 18.7% (37/197), p value = 0.7]. During the 17 week period of the study, the proportion of seropositivity increased which is illustrated in Figure 2 . (Table 1 and Table 2 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint 8 A summary of demographics and clinical phenotype of seropositive children is included Table 1 .

The median antibody titre among the children with PIMS-TS (60.3 AU/mL, range: 12.3 -170.9) was significantly (p = 0.01) higher when compared to the children without PIM-TS (54.8 AU/ml, range 11.0 -144.3). In addition to antibody titre, age, gender and clinical phenotype were significantly different between seropositive children with PIMS-TS and children without PIMS-TS (Table 2) .

There was no significant difference in the median duration since any proven or suspected COVID-19 illness or COVID-19 contact between the PIMS-TS and non-PIMS-TS groups (3 vs 3.2 weeks, p=0.46).

A total of 55 children presented with PIMS-TS during the 4 month study duration. Clinical presentation of 19 of these children have been previously described [12] . Of the 55 children, 18%

(10/55) had positive SARS-CoV2 RT-PCR test and 80% (44/55) had positive IgG antibody assay.

Nearly half (54%, 30/55) of the children with PIMS-TS required PICU admission. The median antibody titre of children with PIMS-TS needing PICU care was significantly lower (45.72 vs 81.28, p = 0.02) in comparison to children who did not require PICU care (Table 3) . is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint (Table 4) :

Of the 463 children, 13% (62/463) with a median age of 5 years (4 m -17 y) tested positive for SARS-CoV2 by RT-PCR; 60% (37/62) were male. A summary of demographic, clinical presentation, investigations, treatment and outcome of children with RT-PCR positive test is shown in Table 4 .

There were no deaths in our cohort of children.

Studies describing the prevalence of anti SARS-CoV-2 antibodies during the COVID-19 pandemic have been mostly performed in adult populations [4, 13, 14] and paediatric data are lacking particularly from LMIC [5, 7] . To explore the epidemiology of childhood SARS-COV-2 infection in our LMIC setting, we performed SARS-CoV-2 serology on blood samples from children attending a tertiary hospital during a 4-month period of the COVID-19 pandemic in Chennai. We observed a seropositivity of 19.6% in this hospitalised cohort of children, similar to the 21.5% observed in a serosurvey performed by the ICMR among the general population of Chennai during the same period [15, 16] . There was variation in seropositivity among different age groups, however this may not reflect the true paediatric population prevalence because we only sampled children admitted to hospital. It is therefore difficult to infer whether the difference in seropositivity is due to community exposure or varied immunological responses and susceptibility to infection in younger children. Seroprevalence has been reported variably among children [4] [5] [6] [7] [8] 17 ] (<1% to 55%). The seroprevalence in our cohort (19.6%) cannot necessarily be directly compared with those of other studies, given the dissimilarities in population, study-setting, demographics and is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint local SARS-CoV-2 transmission dynamics. Further research is indeed required to understand the differences in infection dynamics between different groups of children as well as to explain the differences across geographic areas.

Over the course of our study, we observed an expected increase in seropositivity among Our study has limited generalisability because it is a single institution study with opportunistic sampling of children attending hospital for medical care for diverse reasons. In addition, antibodies detected in infants may have been transplacentally acquired, though we excluded neonates. We also did not sample children longitudinally, and therefore measurements from seropositive is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint children may have fallen below the limit of detection of the assay due to the time point at which they were sampled.

Despite limitations, our study has strong implications. Firstly, a seropositivity of 19.6% among our cohort of children displays a strong correlation with the general population prevalence. Second, our results suggests that quantitative antibody analysis may be helpful in disease stratification.

However, further immunological studies are needed to understand the pathogenesis of SARS-CoV2 infection and disease among children. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint multicentre cohort study. Archives of disease in childhood. 2020 Nov 10.

[9]

ICMR. List of IgG ELISA/CLIA kits for COVID-19 Validated by ICMR identified validation centres. Icmr 2020; 1-2.

[10] Guidance document on appropriate management of suspect or confirmed cases of COVID-19, https://www.mohfw.gov.in.

[11] RCPCH. Paediatric multisystem inflammatory syndrome temporally associated with COVID-. CC-BY-NC-ND 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint multisystem inflammatory syndrome (MIS-C). Pediatrics. 2020 Dec 1;146(6). is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted February 1, 2021. ; https://doi.org/10.1101/2021.01.29.21250660 doi: medRxiv preprint

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