|Year : 2022 | Volume
| Issue : 5 | Page : 66-70
Seroprevalence of COVID-19 antibody among children aged 5–17 years in an urban and rural area of Ernakulam District, Kerala
Saanu Sidharthan1, Seenu Shaik1, Chitra Tomy2, K Sreelakshmi Mohandas2, B Poornima3, Paediatric COVID19 Seroconversion Group4
1 MPH Scholar, Department of Community Medicine and Public Health, Amrita School of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India
2 Assistant Professor, Department of Community Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
3 Assistant Professor, Department of Microbiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
|Date of Submission||10-Aug-2022|
|Date of Decision||19-Aug-2022|
|Date of Acceptance||24-Aug-2022|
|Date of Web Publication||11-Nov-2022|
Department of Community Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: The age group of 5–17 years belongs to the vulnerable segment of the population for COVID-19 infection in India. Seroprevalence in this population can therefore allow inferences to be made about the extent of infection. Objectives: The objective of this study was to assess the seroprevalence and to determine the factors associated with COVID-19 antibody among children aged 5–17 years in an urban and rural area of Kochi, Kerala. Methods: A community-based cross-sectional study was undertaken in the urban and rural field practice areas of the community medicine department in a medical college, Kochi. A semi-structured questionnaire was used to collect information about sociodemographic data, history related to COVID-19, and the severe acute respiratory syndrome coronavirus 2 antibody test result. Blood samples were collected and tested for the presence of COVID-19 antibodies using the Wantai test kit after attaining informed assent from the parent/guardian. Results: The seroprevalence of the COVID-19 antibody was 48.3% among participants. The seroprevalence of COVID-19 antibody was higher among children of mothers with skilled/unskilled occupation, residents of rural area, above poverty line category, those with a history of COVID-19, and those who had a history of contact with COVID-19-positive patients. Conclusion: Half of the study population were COVID antibody positive, and the rest were at risk of infection. Therefore, adherence to COVID-19 guidelines is essential to control further spread of infection among children.
Keywords: Antibody, children, COVID-19, seroprevalence
|How to cite this article:|
Sidharthan S, Shaik S, Tomy C, Mohandas K S, Poornima B, Paediatric COVID19 Seroconversion Group. Seroprevalence of COVID-19 antibody among children aged 5–17 years in an urban and rural area of Ernakulam District, Kerala. Indian J Public Health 2022;66, Suppl S1:66-70
|How to cite this URL:|
Sidharthan S, Shaik S, Tomy C, Mohandas K S, Poornima B, Paediatric COVID19 Seroconversion Group. Seroprevalence of COVID-19 antibody among children aged 5–17 years in an urban and rural area of Ernakulam District, Kerala. Indian J Public Health [serial online] 2022 [cited 2022 Dec 4];66, Suppl S1:66-70. Available from: https://www.ijph.in/text.asp?2022/66/5/66/360647
Paediatric COVID19 Seroconversion Group
(6th- 8th Authors)
Dr. Leyanna Susan George - Associate Professor
Dr. Navami S - Senior Resident
Dr. Minu Maria Mathew - Biostatistician
Department of Community Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
| Introduction|| |
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first isolated from patients in China in January 2020. The novel coronavirus disease otherwise known as COVID-19 was declared a public health emergency of international concern in March 2020.,
Globally, as of October 4, 2021, there have been around 234 million confirmed cases of COVID-19, including 4 million deaths, reported to the WHO. The most common mode of transmission is through droplets expelled while talking, coughing, or sneezing and can also occur through contact, surface spread, and aerosols. Exposure to an infected person for a prolonged period and briefer exposures to symptomatic patients pose an increased risk for transmission, while brief exposures to asymptomatic contacts are less likely to result in transmission.
Viral shedding begins about 2–3 days before the onset of symptoms and is high during the 1st week of infection at a time in which symptoms are mild, which might explain the efficient transmission of SARS-CoV-2, as the infected persons may be infectious before they are aware of the infection.
Serological tests can help in the diagnosis as well as serve as a measurement of responses to novel vaccines. However, the presence of antibodies may not indicate immune status as all antibodies produced in response to infection are not neutralizing. Whether the presence of antibody changes the susceptibility to subsequent infection or how long the antibody protection lasts, cannot be predicted.
The seroprevalence of SARS-CoV-2 antibodies will help to identify mild and asymptomatic cases in the community who might not have received RT-PCR testing. Hence, it is critical to understand the transmission dynamics of the virus, estimate total infections, and inform the possibility of transmission interruption.
As of September 30, 2020, globally, the second highest number of confirmed cases were reported in India. Considering the distinct population characteristics of India such as its size, diversity, and uneven distribution, case-based surveillance data alone cannot assess the extent of transmission of SARS-CoV-2. Besides, Indian cities represent challenging conditions for COVID-19 control, with some of the world's highest population densities and contact rates.
In India as well as in the state of Kerala, we have limited literature regarding the seroprevalence of COVID-19 among children below 18 years of age. Most research point out that, in childhood, viral shedding may increase with increasing age. In addition, prior published research showed that young children were more likely to have asymptomatic infections than older individuals. Therefore, surveillance of antibody seropositivity in a population can allow inferences to be made about the extent of infection. Our main aim of the study was to assess the seroprevalence of COVID-19 antibody among children aged 5–17 years and to determine the factors associated with seropositivity of COVID-19 among the same population group.
| Materials and Methods|| |
A community-based cross-sectional study was undertaken between September 2021 and November 2021 in the rural and urban field practice areas of the community medicine department of a medical college in Kochi. The study participants included children aged 5–17 years of age, while children infected with SARS-CoV-2 at the time of the study were excluded from the study. From each field practice area, 4–5 schools were selected randomly and the available participants were invited to take part in the study. The sample size was calculated based on the seroprevalence of 55.7% reported by a multicentric seroepidemiological study done by Misra in India among children aged <18 years. Sample size was calculated manually using the formula n = Z (α/2)2 × p (1 − p)/d2 where Z (α/2) = 1.96, relative precision (d) = 10%, and p = seroprevalence of 55.7% (reference). With 95% confidence interval the minimum calculated sample size was 315. A total of 183 and 166 participants were included from urban and rural areas, respectively. Institutional ethics committee approval was obtained before data collection (ECASM-AIMS-2021-382).
A semi-structured questionnaire was used to collect information about sociodemographic data, history related to COVID-19, and the SARS-CoV-2 antibody test result. The WANTAI SARS-CoV-2 Ab Rapid Test was used to assess for COVID-19 antibody. The test is a lateral flow assay for the qualitative detection of total antibodies (including IgG and IgM) to SARS-CoV-2 in human serum, plasma, and venous whole blood. The test positivity is indicative of recent or prior infection. The test kit reports to have 100% sensitivity and 98.8% specificity.
The questionnaire was prepared in English and was translated into Malayalam. Information was collected after obtaining written informed consent from the parent/guardian and after explaining the study by a face-to-face interview. Data collected through interview were entered into Google Forms. Four milliliters of blood was drawn from the left arm in a sitting position while adhering to strict aseptic precautions. The samples were transported to the microbiology laboratory in an ice pack cooled box within 4 h of blood collection. Serum was separated and stored at 4°C or frozen to −20°C. The antibody tests were run using Wantai test kit by trained personnel in the microbiology laboratory. The results were communicated to the research participants within 2 weeks by telephonic communication. Data were analyzed using SPSS v. 20.
The data were analyzed using IBM SPSS Statistics for Windows, Version 20.0, Armonk, NY: IBM Corp.. Seroprevalence of COVID-19 antibody was expressed in percentage. Chi-square test was done to find the association for various risk factors for seropositivity among children aged 5–17 years. Multivariate logistic regression was used to determine the independent predictors for seroprevalence of COVID-19 in children aged 5–17 years, expressed with odds ratio and their 95% CIs.
| Results|| |
A total of 349 participants were included in the study with 183 participants from an urban area and 166 participants from a rural area. The mean age of the study population was 12.7 ± 2.86 years. Majority (71.6%) were in the age group of 12–17 years, 57.3% were female, and 73.26% were in the above poverty line (APL) category. About 9.4% of parents were frontline workers and 66.7% were health-care workers. With regard to fathers' occupation, majority were doing skilled work/unskilled work (54.4%) and others doing professional work (45.6%). With regard to mothers' occupation, majority were doing skilled work/unskilled work (87.1%) and others were professional workers (12.9%).
Among the study population, 9.2% and 13.8% had a history of COVID positive in the past 3 months and 1½ years, respectively. Out of the study population, 14.9% had a history of contact with COVID-positive patients in the past 3 months, 7.4% had a history of travel in the past 14 days, 9.7% had a history of attending a social gathering in the past 14 days, and 15.4% had a history of taking part in outdoor games.
Out of 349 blood samples collected, three samples were not sufficient to run the test. Hence, antibody test was done on 346 samples. Out of 346 children, 48.3% ± 5.28 (167) were positive for COVID-19 antibodies and 51.7% (179) were negative for COVID-19 antibodies.
On univariate analysis, age group 5–11 years (P = 0.028), mother's occupation (P = 0.001), rural population (P = 0.033), and APL category (P = 0.005) were significantly associated with COVID-19 antibody positivity among children aged 5–17 years. Furthermore, history of being COVID positive in the past 3 months (P = 0.01), 1.5 years (P = 0.01), and history of contact with a COVID-positive patient in the past 3 months (P = 0.01) were significantly associated with COVID-19 antibody positivity among children aged 5–17 years [Table 1].
|Table 1: Factors associated with seroprevalence among children aged 5-17 years|
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On multivariate analysis of factors associated with seroprevalence of COVID-19 antibody, rural population (adjusted odds ratio [aOR]: 1.407 [95% CI: 1.53–1.880]; P = 0.021), APL (aOR: 1.342 [95% CI: 1.019–1.768]), skilled/unskilled occupation of mothers (aOR: 3.353 [95% CI: 1.510–7.445]), history of being COVID positive in the past (aOR: 9.262 [95% CI: 3.272–26.222]), and history of contact with COVID-positive patients in the past 3 months (aOR: 2.477 [95% CI: 1.060–5.790]) showed an increased risk for antibody positivity among children aged 5–17 years [Table 2].
|Table 2: Multivariable logistic regression to find the independent risk factors for seroprevalence among children aged 5-17 years|
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| Discussion|| |
Our study, done among 349 children aged 5–17 years in a rural and an urban area to assess the seroprevalence of COVID-19 antibodies, showed a prevalence of 48.3%. Slightly higher seroprevalence (55.7%) was observed in a study conducted in five selected locations such as Delhi urban resettlement colony, Delhi rural, Bhubaneswar rural, Gorakhpur rural, and Agartala rural area by Misra among children aged 2–18 years.
According to our study, seroprevalence was significantly higher among 5–11-year-old children. Similar results were released by the fourth national serosurvey among the first age group, whereas in the latter group, it is greater compared to our study results. Higher seropositivity of COVID-19 antibody among the younger age group might be related to the poor adherence to COVID precautions such as handwashing and proper mask usage. The findings of the fourth national serosurvey showed that there was no significant difference in seroprevalence between males and females, which was similar to our study.
In the multicentric study done by Misra, seroprevalence was higher in the urban population, but in our study, seroprevalence was higher among the rural population. This can be explained by the fact that the rural area under our study was a coastal area and had a higher population density. However, the national serosurvey observed no difference in both rural and urban areas.
According to our findings, seropositivity for COVID-19 antibody was higher among those who belonged to the APL category than those who belonged to the below poverty line (BPL) category. However, there was no statistically significant difference between seropositivity among the APL/BPL categories according to the COVID-19 serosurveillance report by the Department of Health and Family Welfare, Government of Kerala. Majority of parents who belong to the APL category had type of jobs which required physical presence and had a risk of physical contact with infected persons which may be the reason for the higher seroprevalence among their children.
In the present study, most of the participants who had a history of COVID disease in the past 3 months had antibodies, whereas 43.3% of those who did not have such a history had positive test results. In the present study, a vast majority of participants who had a history of being COVID positive in the past 1½ had antibodies, whereas 41.8% of those who did not have such a history had positive test results.
Majority of children included in our study who had a history of being in contact with COVID-positive patients were positive for COVID antibodies. According to research done by Barranco-Trabi et al., it was observed that symptomatic patients with close contact to COVID-19-positive patients were four times more likely to test positive.
This study was done in conveniently selected urban and rural field practice areas of a medical college in Kochi. Because of COVID-19 guidelines and precautions, access to many places and houses was limited and children under 5 years old had to be excluded from the study.
| Conclusion|| |
In our study, about half of the children population aged 5–17 years were positive for COVID-19 antibody. The seroprevalence of COVID-19 antibody was higher among children of mothers with skilled/unskilled occupation, residents of rural area, APL category, those with a history of COVID-19, and those who had a history of contact with COVID-19-positive patients. As more than half of the child population are still at risk of being infected with COVID-19, it is advisable to make necessary policy changes regarding vaccination in this age group with the help of further in-depth research. Continued extension of testing capacity is required to improve the infection-to-case ratio, especially in geographic areas with high seroprevalence but low case reporting.
| Acknowledgment|| |
The authors wish to thank the sincere effort put forth by Mrs. Prajitha, Mrs. Priyanka Prasad, Mr. Ratheesh Kumar, Mrs. Prameela TK, Mrs. Kavitha P, Mrs. Sunitha Praveen, Mrs. Teresa Albert Mrs. Sreemole, and all the staff of ACHTC, Njarakkal, and AUHC, Kaloor, AIMS, for the conduct of the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]