Coronavirus disease of 2019 (COVID-19) is an extremely communicable disease characterized by the serious acute respiratory influenza virus 2, a recently identified novel viral disease (SARS-CoV-2). Hitherto, the quantity of established instances worldwide has reached 135 million, and the number of deaths is 2.9 million. In India, the cases were found to be 20 million and the mortality rate is 3,51,000. This virus was first identified in Wuhan City, Hubei Province in China, at the end of 2019. Until now, it affected more than 200 countries. The treatment pattern and clinical presentations were assessed in COVID 19 patients. A total of 146 patients, severe patients (n = 71) and non-severe patients (n = 75) where included in the study. The mean age of the study population was found to be 58.76±14.32 and the most common symptoms of patients include fever, fatigue, dry cough, and diarrhea there is no statistically significant difference in the clinical features between severe and non-severe patients. There is no significant difference in the laboratory findings except lymphocyte count, CORADS and N/L ratio between severe and non-severe patients. COVID-19 affects all age groups especially the elderly. The risk for severe illness with COVID-19 increases with age. COVID 19 patients were presented with various the risk factors and the clinical features in the severe and non severe conditions patients, our study shows great significance to prevent the patient turning to critical condition during diagnosis and treatment.

Introduction: Herd immunity is a traditional concept nothing but a form of indirect protection from contagious diseases. In a mass community, there is no need to be everyone immune. If a high proportion of members in the community are immune, spreading of the disease is reduced even to non-immunized patients. This study offers an overview of vaccine-induced herd immunity importance in this pandemic and how it will be achieved. Methodology: The data of basic reproduction number Ro values for COVID 19 of 10 weeks in India which were estimated by Ro package in R software are extracted from a research article (reference no.4) and taken the mean Ro value due to fluctuations as well as to avoid great errors by using MS Excel. Herd immunity is calculated by using a standard equation stated as R=(1-Pc )(1-P1)Ro   Results:  The mean basic reproduction number Ro for COVID 19 in India was calculated as 1.671 by using MS excel and the herd 3 determines that only 40.16% proportion of individuals need to immunized through a vaccine to achieve herd immunity towards COVID 19 in India. Conclusion: This study estimates mean base reproduction Ro as 1.671 and Herd Immunity Threshold (HIT) as 40.16% by using past data. This study concludes that vaccine-induced herd immunity helps us by playing a key role to eliminate novel coronavirus.