COVID-19 Seroprevalence Study of an Indian Diagnostic Laboratory - Report on Gender and Age Analysis
Total Page:16
File Type:pdf, Size:1020Kb
Asian Journal of Health Sciences 2020, 6(2):16 Open Access Full Text Article Research Article COVID-19 seroprevalence study of an Indian Diagnostic Laboratory - Report on gender and age analysis Kallathikumar Kallathiyan, Amruta Velumani, Sandhya Iyer*, Krishnakumar Sivapandi, Anand Velumani ABSTRACT In COVID-19 the extent of the impact on exposure, symptoms, recovery remains minimally explored as the spectrum is challenging to study across geographies. The aim of our study report was to ex- Use your smartphone to scan this plore seroprevalence in a pan-India cohort of Asian Indians across different age groups. Covid-19 QR code and download this article antibodies were tested from a total of 1,36,210 Asian Indians inclusive of 97,124 males and 39,086 females, respectively. Testing for covid-19 antibodies was done by electrochemiluminescence im- munoassay (ECLIA) and enzyme-linked immunosorbent assay (ELISA). Analysis for seroprevalence found the frequency to be 19%. The percent positives were higher among females at 21%, com- pared to males at 19%, and the difference was found to be statistically significant at p<0.0001. Further, age group-wise analysis found seroprevalence between age groups of 21 - 80 years to be significant at p < 0.0001. Our study found higher seroprevalence among females, which is inline with many small cohort studies published online. Key words: Antibody, Coronavirus, COVID-19, Females, India, Males, Pandemic INTRODUCTION age group of 60 - 79 years to be the most vulnera- ble, with 51.2% having succumbed to covid-19 be- The coronavirus disease of 2019 (COVID-19) caused ing over 60 years of age 3. Another following report by the SARS-CoV-2 has had an enormous impact on from New Delhi detected 43% of the covid-19 deaths global healthcare infrastructure. The social impact to have taken place in the younger age groups of be- of the pandemic include, loss of livelihood for many, tween 30 - 44 years and 45 - 59 years, respectively 4. apart from anxiety around the cause for fatality. Apart The wide spectrum in the age group around the fatal- from understanding the mechanism of infection, de- ity of covid-19 in the country does add to a lot of epi- Immunoassay Division, Thyrocare termining risk factors on the cause, and the spread Technologies Limited, Plot demiological dilemma wherein risk stratification be- of the pandemic has generated heterogeneous infor- No.D37/1,TTC Industrial area, MIDC, comes difficult. mation deluge. The delay in making available testing Turbhe, Navi Mumbai - 400703, India In the case of diagnosis of covid-19, RT-PCR has been kits, variations in diagnosis criteria, the inherent risk Correspondence recommended, and many comparison studies have around sample collection for reverse transcriptase- Sandhya Iyer, Immunoassay Division, detected molecular analysis to be better in terms of Thyrocare Technologies Limited, Plot polymerase chain reaction test (RT-PCR), and imple- sensitivity and specificity. The type of specimen tested No.D37/1,TTC Industrial area, MIDC, mentation of different intervention strategies at dif- and the time period has been shown to impact diag- Turbhe, Navi Mumbai - 400703, India ferent stages of the pandemic has made epidemio- nosis with RT-PCR, as early period serum samples Email: [email protected] logical data comparison even within the country, a were detected to be negative, while the respiratory History difficult task. Answers to a lot of questions around specimen was positive 5. Pre-analytical and analytical • Received: 2020-10-05 the spectrum of disease severity ranging from asymp- variables have been shown to highly impact diagnos- • Accepted: 2020-10-27 tomatic to a mild symptomatic, severe disease requir- • Published: 2020-11-10 tic accuracy of RT-PCR, including quality of the sam- 1 ing hospitalization and fatality are critical . The re- ple, wherein sputum has been detected to be better DOI : 10.15419/ajhs.v6i2.478 curring incidences of coronavirus infection first in the than oropharynx, which is superior to the nasophar- year 2003, and then 2012, and the current 2019, has ynx 6. Testing for total (IgG and IgM) covid-19 anti- been overwhelming both in terms of healthcare man- bodies adds convenience to the sampling process and agement, through its mode of transmission, higher feasibility to use for large scale population monitor- Copyright risk of death among the vulnerable, increased risk ing. The added advantage of studying covid-19 an- © Biomedpress. This is an open- for healthcare workers, and the significant number of access article distributed under the tibodies lies in the general efficacy of the serological 2 terms of the Creative Commons deaths . In the case of India, one report by the Indian assays among late presenting patients and those with Attribution 4.0 International license. Council of Medical Research (ICMR) highlighted the low viral load 7. Antibody tests have been viewed as an Cite this article : Kallathiyan K, Velumani A, Iyer S, Sivapandi K, Velumani A. COVID-19 seroprevalence study of an Indian Diagnostic Laboratory - Report on gender and age analysis. Asian J. Health Sci. 2020; 6(2):16. 1 Asian Journal of Health Sciences 2020, 6(2):16 excellent companion for RT-PCR tests in SARS-CoV- females. The seroprevalence found in our analysis was 2 as they aid in identifying asymptomatic individu- 19%. In case of females the percent positive was found als. Though the window period for antibody testing to be higher at 21%, compared to males at 19%, and in covid-19 is debated to lie between 10 - 14 days after the difference was statistically significant at p < 0.0001. symptom onset, they are important for epidemiolog- Further, age group analysis was also done to under- ical investigations to monitor the extent and preva- stand if there was any difference in seroprevalence, lence of infection 8. impacting age-related susceptibility. The results have The aim of the present study was to assess the sero- been summarized in Table 1. prevalence for the covid-19 antibody in a pan-India Analysis of significance in seroprevalence between cohort of Asian Indians across different age groups. different age groups found the difference in percent This is crucial for risk stratification and designing positive between age groups of 21 – 80 years to be sig- public health measures. A nationwide serosurvey nificant at p < 0.0001. The seroprevalence of above that is targeting specific strata, including different age 20% was found in the age group of > 40 years. Our groups and gender, will aid in determining the im- analysis also found the age group of between 61 – 80 pact of containment measures, as well as behavioral years to exhibit maximum exposure. changes. An age group serosurvey analysis also aids Further analysis of gender among different age groups in determining the high-risk category and identify- found the percent positive difference between males ing the mode of transmission across different sub- and females to be significant up till 60 years of age at sections of society. p = 0.0025 among children and adolescents, while at p < 0.0001 for the adults. Maximum exposure among MATERIALS - METHODS both males and females was detected in the age group This observational report includes data from samples of between 61 – 80 years. The seroprevalence was processed in a reference laboratory and not a hospital- found to be consistently high among adult females in based setting. No patient identifiers have been used the cohort. in any part of this report, and hence the need for in- formed consent and review board approval does not DISCUSSION fit as a necessity. Data from a total of 136,210 samples The covid-19 pandemic continues to evolve in terms tested for the covid-19 antibody assay have been used of disease severity, recovery, and fatality rates. The for this analysis. developed nations of the world are challenged by Total covid-19 antibody testing was done by the tech- high death per million (DPM), while the economi- nology of electrochemiluminescence immunoassay cally weaker geographies are under pressure to tackle (ECLIA), and that for IgG was done by enzyme-linked the high volume of testing, to effectively control in- immunosorbent assay (ELISA). The approved com- fection spread. The pandemic has posed many chal- mercial kits for ECLIA include the Cobas® Elecsys lenges, from the need to identify the spectrum of dis- Anti-SARS-CoV-2 (Roche Diagnostics, GmbH) and ease severity to studying transmission and rates, and the SARS-CoV-2 Total (COV2T, Siemens Healthcare lastly, the factors that promote the risk of fatality from Diagnostics Inc., USA). The approved commercial severe illness stage 1. Age has been classified as one of kits for ELISA include the COVID-19 IgG ELISA Kit the risk factors for infection, and many studies have (Omega Diagnostics, UK) and ErbaLisa® COVID-19 identified the risk of infection among the elderly to be IgG (Calbiotech Inc. USA). The ECLIA assay in- affected by other age groups 9,10. Studies on contact volved the use of a recombinant protein represent- rate, and infection transmission across different age ing the nucleocapsid (N) antigen to detect antibod- groups, have detected the old age group to be suscep- ies against the SARS-CoV-2, and also a sandwich im- tible, and the impact of social distancing on pandemic munoassay using acridinium ester chemiluminescent control to depend on the role of different age groups technology. In the case of ELISA, the principle was a in transmission 9. semi-quantitative plate-based assay to detect COVID- Age group analysis becomes a crucial factor in many 19 IgG antibodies. Result interpretation was made us- epidemiological aspects of covid-19, right from chart- ing the cutoff index (COI) as specified by the manu- ing exposure to susceptibility, contact tracing, and facturer.