Persons previously infected with COVID-19 might need to take only 1 Covaxin dose: Study

Persons who have been previously infected with COVID-19 might need to take only a single dose of Covaxin, a new ICMR study revealed. As a part of this research, blood samples were collected from 114 healthcare professionals and frontline workers who received Covaxin at vaccination centres in Chennai from February to May this year. It found that the participants who had contracted the novel coronavirus in the past and taken one dose had similar antibody levels to those who were fully inoculated without a history of COVID-19.

Thus, the ICMR observed that persons with no prior SARS-CoV-2 infection can be prioritized to complete the two doses of Covaxin. However, it noted that these preliminary findings have to be confirmed with large-sized cohort studies in order to reach a definite conclusion. It also stressed that both vaccine doses would be ideal even for previously infected individuals owing to the occurrence of variants of concern.

The study stated, "In conclusion, almost all participants with prior COVID-19 infection, except two, had detectable antibodies at the time of vaccination. This study offers evidence in support of public health-oriented and immunologically sustained vaccine strategies. If our preliminary findings are confirmed in large population studies, a single dose of BBV152 vaccine may be recommended to previously confirmed SARS-CoV-2 infected individuals so that the naïve individuals could attain the larger benefit of a limited vaccine supply."

Covaxin demonstrates high efficacy

COVAXIN is a Whole Virion Inactivated Coronavirus Vaccine developed by Bharat Biotech in collaboration with the ICMR and the National Institute of Virology (NIV). While the phase 3 trials entailed 25,800 participants between 18-98 years of age including 10% over the age of 60, the analysis was conducted 14 days after administering the second dose of the vaccine. It has shown overall 77.8% efficacy and 93.4% efficacy against severe COVID-19 disease as per the final results. On the other hand, efficacy data demonstrates 63.6% protection against asymptomatic COVID-19 disease.

Most importantly, it has proven to neutralise variants such as B.1.1.7 (Alpha), B.1.617 (Kappa), B.1.351 (Beta) and B.1.617.2 (Delta). Under the aegis of the ‘Mission COVID Suraksha- the Indian COVID-19 Vaccine Development Mission’, the Haffkine Biopharmaceutical Corporation Ltd, Mumbai; Indian Immunologicals Limited in Hyderabad and Ankleshwar and Bharat Immunologicals Biologicals Limited in Bulandshahr have also been permitted to produce Covaxin. A total of 48,21,24,952 persons have been inoculated whereas 14,15,06,099 of them have received the second dose of the vaccine too.