Original Research Article
Year: 2021 | Month: April-June | Volume: 6 | Issue: 2 | Pages: 54-63
DOI: https://doi.org/10.52403/gijhsr.20210408
SARS-CoV-2: Comparison of Active Immunity Acquired by Natural Exposure versus Inoculation of HCW
Shagun Bhatia Shah1, Rajiv Chawla2, Anurag Mehta3, Nitin Bansal4, Chamound Rai Jain5, Anuj Prakash6, Shalini Mishra7, Sudhir Kumar Rawal8
1Consultant Anaesthesiologist; Rajiv Gandhi Cancer Institute and Research Centre; Sec-5; Rohini; Delhi.
2Director Anaesthesiology; Rajiv Gandhi Cancer Institute and Research Centre;
3Senior Consultant and Head; Laboratory and Transfusion Services; Rajiv Gandhi Cancer Institute and Research Centre; Sec-5; Rohini; Delhi.
4Infectious Disease Officer; Rajiv Gandhi Cancer Institute and Research Centre; Sec-5; Rohini; Delhi.
5Consultant Cardiologist; Rajiv Gandhi Cancer Institute and Research Centre; Sec-5; Rohini; Delhi.
6Senior Biochemist (Consultant I) & Quality Manager- Laboratory Services; Rajiv Gandhi Cancer Institute and Research Centre; Sec-5; Rohini; Delhi.
7Consultant Paediatric Surgical Oncology; Rajiv Gandhi Cancer Institute and Research Centre; Sec-5; Rohini; Delhi.
8Managing Director and Consultant Surgical Oncology; Rajiv Gandhi Cancer Institute and Research Centre; Sector -5; Rohini; Delhi.
Corresponding Author: Shagun Bhatia Shah
ABSTRACT
Background: The immune response to vaccination is not expected to be the same in COVID-19 survivors and COVID-naïve population. There is a deficiency of specific guidelines regarding vaccination (number and temporal spacing of doses) for the burgeoning subset of population which has recovered from COVID-19 due to paucity of literature.
Methodology: This prospective, observational, single-centric, case-control study compares the IgG-antibody count at two time-points (post first and second inoculation) in 33 COVID-survivors Group-P) and 31 COVID-naïve (Group-N) health care workers. Adverse events post-inoculation were recorded. Paired and independent sample t-tests were used for intra and intergroup comparison, respectively. Data was expressed as bar-charts, dotted box-whisker and dot-line plots. P-value<0.05 was considered statistically significant.
Results: The mean IgG count in Group-P was 23.58±2.06 arbitrary units (AU) whereas that in Group-N was 12.20±8.01 AU after first inoculation. All Group-P patients had a count ≥ 20AU. The mean IgG-count in Group-P was 25.48±2.79AU whereas that in Group-N was 16.40±6.55AU after the second dose of vaccination. 10 HCW in Group-N but none in Group-P developed COVID-19 after second inoculation.
Conclusion: All COVID-naïve persons must mandatorily be administered both doses of vaccination (their IgG-titres reach protective levels only after the second inoculation). The second inoculation provides no additional benefit in COVID-survivors (2 crore 73 lac Indians) since their IgG-counts cross the 18AU mark (high protection), after the first dose itself. Triage of this resource to COVID-naïve population can ameliorate vaccine-shortage. Separate explicit guidelines for vaccination of corona-survivors may need formulation on a priority basis. Although both are protective, natural infection confers more robust immunity than vaccination. Pre-emptive paracetamol nullifies most post-inoculation adverse effects.
Keywords: Adverse events; COVID-naïve; COVID-survivor; Immunity; Vaccination.