key: cord-1025644-bmzm879y authors: Misra, P.; AIIMS, WHO Unity Seroprevalence study team of title: Serological prevalence of SARS-CoV-2 antibody among children and young age (between age 2-17 years) group in India: An interim result from a large multi-centric population-based seroepidemiological study date: 2021-06-16 journal: nan DOI: 10.1101/2021.06.15.21258880 sha: 31892a2b934b45686345b842ff481ab2445fa850 doc_id: 1025644 cord_uid: bmzm879y Background: Concern has been raised in India regarding the probable third wave of COVID-19 where children and young age group is thought to get affected the most. There is a lack of serological prevalence data in this age group. We have some interim data from our research for WHO unity protocol, which might help policymakers and the research community to answer such questions based on evidence. Hence, we conducted a study to compare the COVID -19 sero-positivity rate between children and adults Methods/Materials: This is part of an ongoing large multi-centric population-based sero-surveillance study. The study is being conducted in five selected states with a proposed total sample size of 10,000. We have data of 4,500 participants at the time of midterm analysis from four states of India. Total serum antibody against SARS-CoV-2 virus was assessed qualitatively by using a standard ELISA kit. Here we are reporting the interim data of serological prevalence among children aged between 2 to 17 years along with a comparison with [≥]18-year old participants. Results: The data collection period was from 15th March 2021 to 10th June 2021. Total available data was of 4,509 participants out of which <18 years were 700 and [≥]18 years was 3,809. The site-wise number of available data among the 2-17 year age group were 92, 189, 165, 146 and 108 for the site of Delhi urban resettlement colony, Delhi rural (Villages in Faridabad district under Delhi NCR), Bhubaneswar rural, Gorakhpur rural and Agartala rural area respectively. The seroprevalence was 55.7% in the <18 years age group and 63.5% in the [≥] 18 year age group. There was no statistically significant difference in prevalence between adult and children. Conclusion: SARS-CoV-2 sero-positivity rate among children was high and were comparable to the adult population. Hence, it is unlikely that any future third wave by prevailing COVID-19 variant would disproportionately affect children two years or older. After the introduction of an infectious agent, the progression of the disease is to a large extent determined by host factors. The age of the host, along with many other factors e.g. pre-existing immunity, co-morbidities etc. plays an important role in determining the further course of the event. [1] Children, particularly aged 5-18 years attend schools. It is commonly believed that classrooms could become outbreak cluster. [2] It is further assumed that those children could then bring the infection home and pass it on to their elderly grandparents who are at a higher risk of dying due to COVID-19. Because of their reasoning, globally there has been occurrence of closure of schools and thereby disadvantaging children in receiving education. [3, 4] This line of reasoning presumes that children have a much lower rate of infection as compared to the community at large. [5, 6] However, strong evidence is lacking to support this assumption. We, therefore, undertook a community-based sero-survey for COVID-19 among a population older than two years. The objective of the study was to compare the COVID-19 sero-positivity rate between children and adults. Design and study setting: This is part of an ongoing multi-centric population-based, agestratified prospective COVID-19 sero-prevalence study under WHO (World Health Organisation) Unity studies. [7] It is being conducted in five selected sites in India. The sites are AIIMS (All India Institute of Medical Sciences), New Delhi; AIIMS, Bhubaneswar, Odisha; AIIMS, Gorakhpur, Uttar Pradesh; JIPMER (Jawaharlal Institute of Postgraduate Medical Education & Research), Puducherry and Agartala Medical College, Tripura. In each site both urban and rural area population have been planned to be included. In Delhi, the urban area was . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 16, 2021. ; https://doi.org/10.1101/2021.06.15.21258880 doi: medRxiv preprint Ab ELISA kit, Wantai SARS-CoV-2 Diagnostics) as per the manufacturer's protocol. WANTAI SARS-CoV-2 Ab ELISA is an enzyme-linked immunosorbent assay (ELISA) for the qualitative detection of total antibodies against S-RBD SARS-CoV-2 virus in human serum or plasma specimens. It has a sensitivity of 94.4% and a specificity of 100%. [8] Specimens with an absorbance to Cut-off ratio of ≥ 1.0 was considered as positive. Data collection was done using tablet-based Epi Collect 5 mobile and web-based application was filled for each participant, which included information on age, sex, blood group, symptoms history in past 3 months, complications, contact history, vaccination status and use of mask. Once uploaded, the form was downloaded in Microsoft-Excel data format and merged with registration forms filled at the time of sample collection based on unique identification numbers. The data were extracted in Microsoft excel and analysed in Stata V12. Categorical variables were expressed by proportion whereas the continuous variables were expressed by median, mean and 95% confidence interval. To find the statistical difference, the chi 2 test was done between categorical variables. The level of significance was taken at 0.05. The corrected estimate was calculated by adjusting the test kit accuracy using the following formula. [9] Result The data collection period was 15 th March to 31 st March 2021 (the second wave started April The total number of participants in the 2-17 years age group positive for SARS-CoV-2 antibody was 390/700 (55.7%). The prevalence for the adult participants was 2,421/3,809 (63.5%). The site-wise prevalence in these two age group was almost similar except in Agartala site. (Table 1) Irrespective of the age groups, rural sites had lower sero-positivity compared to the urban site (At Delhi). Within the rural sites, children had slightly lower sero-positivity compared to adults. However, this differential prevalence was not observed in the urban site. (Table 1A) The prevalence in children was slightly more among female participants compared to male is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 16, 2021. ; https://doi.org/10.1101/2021.06.15.21258880 doi: medRxiv preprint almost identical sero-positivity rate (42.4% and 43.8%) which was lower than the rate observed for children aged 10-17 years (60.3%). (Table 2) Discussion: There was a slightly higher sero-positivity rate observed among female children. This finding was in contrast to the meta-analysis where it was shown that the prevalence is higher in men. [10] This may be a chance finding due to small number of data available at the time of midterm analysis. The higher seropositivity rate in children aged 10-17 years may be reflective of their higher mobility and independence compared to the younger children. As reported in the literature, a large proportion of children (50.9%) had asymptomatic COVID-19 infection. [11] In India, sero-prevalence among children and younger age group were estimated as a part of a larger nationwide survey on adult age group. The second nationwide sero-prevalence study done in August-September 2020 had reported 9.0% seropositive among 3,021 children aged 10-17 years. [12] while in our study it is 60.3%. One hospital-based study in Chennai had reported 19.6% prevalence in the age group of 1 month to 17 years. [13] Delhi Urban: During the first wave of the pandemic in India, the worst affected areas were the large urban areas, including Delhi. We collected the data during the second fortnight of March 2021. This was the time when the first wave was subsiding and the second wave had not yet started. Results show that a large majority of the population had already been infected by the time we conducted the study at Delhi urban site which belongs to lower and middle socioeconomic strata population and very congested neighbourhood. The obliteration of any difference in sero-positivity rate between children and adult suggests that as the disease become generalized, it affects all age groups equally. We found that sero-positivity rate in our study was higher (74.7%) than the fifth sero survey (conducted in January 2021) which reported an overall 56.1% for Delhi and 62.8% for South . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. In a rapidly evolving pandemic, individuals who have been recently infected (< 14 days) may not have developed antibodies. They would have been reported negative in sero-survey. Hence, our findings are likely to be an underestimate. We observe that children had a slightly lower sero-positivity rate compared to adults (55.7% vs 63.5%). These findings are similar to the previously reported evidence which found that children are less affected than the adult age group. [16, 17] During the pandemic schools were closed and children were more likely to have remained indoors compared to adults. For children, the source of infections is likely to be the household adults who brought the infection from outside during livelihood activities. Hence, we can expect some lag in sero-positivity among children. We are not sure if children produce the same level of antibodies as adults when infected. If children produce a lower level of antibodies that might not be detectable by . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted June 16, 2021. ; https://doi.org/10.1101/2021.06.15.21258880 doi: medRxiv preprint Principles of infectious diseases: transmission, diagnosis, prevention, and control COVID-19 in primary and secondary school settings during the first semester of school reopening -Florida Early school closures can reduce the first-wave of the COVID-19 pandemic development Closing schools for SARS-CoV-2: a pragmatic rapid recommendation Epidemiology of COVID-19 Human and novel coronavirus infections in children: a review The Unity Studies: WHO Sero-epidemiological Investigations Protocols: Available from Wantai SARS-CoV-2 Manual Diagnostic Kits: COVID-19 Serology and Molecular Tests. Wantai BioPharm: Available from Adjusting coronavirus prevalence estimates for laboratory test kit error Sex difference in coronavirus disease (COVID-19): a systematic review and meta-analysis Distinct characteristics of COVID-19 infection in children. Front Pediatr findings from the second nationwide household serosurvey Correlation of SARS-CoV-2 serology and clinical phenotype amongst hospitalised children in a tertiary children's hospital in India A look at serological surveys conducted in Delhi Over 56% people in Delhi have antibodies, shows fifth sero survey. Scroll Susceptibility to SARS-CoV-2 infection among children and adolescents compared with adults: a systematic review and meta-analysis The Role of children in the dynamics of intra family coronavirus 2019 spread in densely populated area All India Institute of Medical Sciences, New Delhi 110029, India 2. All India Institute of Medical Sciences, Bhubaneshwar, Odisha-751019 Puducherry-605006, India 5. Agartala Government Medical College, Agartala-799006, India 6. Translational Health Science and Technology Institute