Investigator(s)
| WHO Technical Officer |
Mohammad Ahmad WHO country office, India. NPO (research) Mohammad Ahmad 
|
| Principal Investigator |
Dr. Puneet Mishra Professor, Center for Community Medicine, All India Institute of Medical Sciences, New Delhi-110029 Dr. Puneet Mishra
|
Title(s) and abstract
| Scientific title | Longitudinal follow-up of ongoing Multi-Centric COVID-19, Population-Based Age-Stratified Sero - Epidemiological Prospective Study under WHO Unity protocol in India, Including Cell-mediated Immune Response Post infection/Vaccination: Phase 2 (2022-2023) |
| Public title | Population-based age stratified longitudinal sero-epidemiological investigation and cell-mediated immune response following COVID infection/vaccination |
| Background | In continuation with the ongoing multi-centric sero-prevalence study at AIIMS, New Delhi, under WHO Unity protocol, a cohort of around 10,000 individuals was established from five selected states across India (phase 1 of the study). The sero-prevalence of antibodies (IgG) (March 15 to Dec 31, 2021) was found to be 73%. Though it was hypothesized earlier that after a significant portion of the population, potentially 60 to 70 percent, new variants which are more transmissible can evade these protections. With declining antibody levels, immunity against specific antigen wanes. The adaptive immune responses in COVID-19, both humoral and cell-mediated immunity (CMI) to SARS CoV-2 are crucial for anti-infection activities. Studies show cell-mediated immune response plays a role and can provide protection to the infected individuals. This study proposes to determine the kinetic and longevity of T-cell immune response in COVID-19 individuals. It will also assess the neutralization activity of SARS-CoV-2 antibodies. The ongoing study (Continuation-phase 2) cohort provides an opportunity to a develop reliable longitudinal follow‐up for immunological monitoring, including the kinetics of CMI |
| Objectives | 1. Longitudinal follow up of registered cohort of ten thousand individuals at various sites across India in urban, rural, and tribal population to study – a) Long term changes in SARS CoV-2 seroprevalence over time in different sex and age groups across India in selected cities b) To see the self-reported reinfection and breakthrough infection in the existing cohort over the next two years. c) To study the long-term sequelae of COVID-19 infection among symptomatic, asymptomatic, and vaccinated individuals in this cohort and to see infection fatality ratio in long term for a total of 3 years of follow-up (including sample collected during Phase 1 of the study (Nov. 2020 – Dec. 2021) and Phase 2 for five months (Feb. 2022 – June 2022)). 2. To contribute to an improved understanding of antibody kinetics following COVID-19 infection/ vaccination a) To study the longitudinal pattern of antibody level following vaccination and natural infection) b) In a subset - evaluation of SARS CoV-2 NAbs for understanding immunity to COVID 19 and protective immunity among the recipients of COVID-19 vaccines vs natural infection. 3. To compare the cellular immunity among SARS CoV-2 antibody positive |
| Study Methods | Participants already enrolled in the initial six months will be followed for additional 18 months making the total follow-up period of 3 years, including sample collected during Phase 1 of the study (Nov. 2020 – Dec. 2021). The follow-up will be continued from the activity started in Nov. 2021 to June 2022 and sample collection will be repeated every six months three more times (i.e., Sample 1 – July to Sept 2022, Sample 2 – Jan to March 2023, & Sample 3 – July to Sept. 2023). for objective # 2, Serial sampling of the subset of positive individuals selected from the pre-existing cohort and a PRNT test will be performed for estimation of SARS-CoV-2 neutralizing antibodies (Nabs). This will help us understand the immunity to COVID- 19 and protective immunity among the recipients of COVID-19 vaccines vs natural infection. The enrolled participants will be followed two times more (i.e., Sample 1 – In the month of July to Sept 2022 and Sample 2 – one year apart i.e., in the month of July to Sept 2023). |
| Expected outcomes and use of results | Study is expected to inform on estimates of sero-prevalence of antibodies (IgG) following COVID-19 infection/ vaccination and antibody waning over time, cumulative incidence of infection , fraction of asymptomatic infection, re-infection and/or any breakthrough infection, infection fatality ratio, Neutralizing antibody IgG levels following COVID-19 infection/ vaccination, T cell response elicited by SARS CoV-2 in COVID-19 convalescent and/or vaccinated individuals and establishment of longitudinal sera repository for future use. For objective 3, serial sampling of the same selected 150 subjects will be done 1 year apart in the month of April – June 2023 from the baseline sample (Sample 1), and see its presence even in absence of antibodies to understand the role of cell-mediated immunity in Covid 19. |
| Keywords | Seroepidemiology AIIMS WHO India SARS-CoV-2 |
Research Details
| Student research | No |
| Start Date | 01-Jul-2022 |
| End Date | 31-Dec-2023 |
| Key Implementing Institution | All India Institute of Medical Sciences, New Delhi |
| Multi-country research | No |
| Nationwide research | Yes, with randomly selected geographical areas |
| India, India, India, India | |
| Research Domain(s) | Communicable Disease Research |
| Research field(s) | COVID-19 |
| Involves human subjects | Yes |
| Population-Based Survey, | |
| Data Collection | Primary data |
| Proposal reviewed by other Committee | Final decision available |