ABSTRACT
Background: Various studies have pinned longevity of protective Immunoglobulin-G (IgG) titres at 2-5 months. The robustness and longevity of the IgG antibody response to COVID-19 infection has been gauged in a cohort of 214 single institutional health care workers by serial quantitative immunometric tests. Currently no separate guidelines exist for vaccination of COVID-survivors and this study provides data to fill this lacuna in knowledge. Methodology: Prospective longitudinal panel survey administered to the same cohort of Health Care Workers (HCW) till such time they got vaccinated under Indian Government's free vaccination drive for HCW. Depending upon the date of contraction of infection the HCW could be longitudinally monitored for variable periods (2-9 months). The survey questionnaire comprising multiple-choice, dichotomous, matrix and Likert-scale questions was deployed to the respondents online via email/WhatsApp. Data was expressed as box-whisker plots, trendlines and trend areas. A p-value<0.05 was considered statistically significant. The composite index of 'Effective Immunity' was calculated. Result(s): The mean IgG antibody titre was 11.13+/-8.6AU at 1-2m, 9.68+/-8.9AU at 3-4m, 8.35+/-5.9 AU at 6-7m and 7.87+/-4.4 AU at 8-9m after first symptom, respectively. The lowest titre at all time points was 0 while the highest titres were 46.8 AU, 56.5 AU, 23.4 AU and 17.4 AU at 1-2m, 3-4m, 6-7m and 8-9m, respectively. Conclusion(s): Adaptive active immunity acquired through natural infection may last for at least 9 months post-initial exposure and lies in the moderate protection range in 77% HCW, which can be extrapolated to vaccination and immunity passports. Separate vaccination guidelines are required for COVID-survivors. The first shot of vaccine serves as a booster second exposure/booster dose in all COVID-survivors.HCW with low IgG-titre may suffer from a false sense of security. Periodic quantitative IgG-titre based serological tests can help guide timing of second shot of vaccination and predict likelihood of re-infection.Copyright © 2022 Indian Medical Association. All rights reserved.
ABSTRACT
The inception of the COVID-19 pandemic has jeopardized humanity with markedly dam-pening of worldwide resources. The viral infection may present with varying signs and symptoms, imitating pneumonia and seasonal flu. With a gradual course, this may progress and result in the deadliest state of acute respiratory distress syndrome (ARDS) and acute lung injury (ALI). More-over, following recovery from the severe brunt of COVID-19 infection, interstitial portions of alve-oli have been found to undergo residual scarring and further to have compromised air exchange. Such alterations in the lung microenvironment and associated systemic manifestations have been recognized to occur due to the extensive release of cytokines. The mortality rate increases with advancing age and in individuals with underlying co-morbidity. Presently, there is no availability of specific antiviral therapy or any other definitive modality to counter this progressive worsening. However, we believe principles and advancing cell-based therapy may prove fruitful in subjugating such reported worsening in these patients. This article reviews eminent knowledge and relevant ad-vancements about the amelioration of lung damage due to COVID-19 infection using adipose tis-sue-derived-total stromal fraction (TSF).Copyright © 2022 Bentham Science Publishers.