Critical interpretative synthesis of herd immunity for COVID-19 pandemic

Introduction: Countries globally are evaluating the concept of herd immunity and its critical role in the control of pandemic. The current paper attempts to conduct a critical interpretative synthesis (CIS) on the role of herd immunity in current COVID-19 pandemic. Methods: CIS is tool for developing theoretical framework using interpretation drawn from relevant empirical and non-empirical sources. This review is done by formulating review question for literature search. Purposive sampling of literature was done followed by reciprocal translational analysis of extracted data. Results: Herd immunity is indirect protection from a contagious infectious disease when a population is immune either through vaccination or natural immunity developed through previous infection. The reproduction number for COVID-19 in India was found to be 2.56 and herd immunity threshold as 61%. Discussion: Exposing 71% young population in India to the SARS-CoV-2 infection can achieve herd immunity but with high morbidity as well as mortality. Vaccine are under process. Feco-oral transmission and reinfection of COVID 19 are major factors to develop or break the circle of herd immunity in community. “Immunity passport” can give false sense of security. Surveillance and seroprevalence studies assess immunity status, gradual exposure of infection to younger population and collaborative partnerships on organizations are few strategies to acquire herd immunity. Conclusion: Herd immunity is a measure for prevention and control of COVID-19 pandemic against the backdrop of mortality and morbidity. Vaccine can be boon but if herd immunity is to be acquired by natural infection then preparedness is necessary.