A study done by ICMR’s National Institute of Virology (NIV-Pune) has revealed that; a booster dose of COVAXIN will enhance its efficacy against the Delta variant. The dose can further give protection against the Omicron variants BA.1.1 and BA.2.According to the research paper published by NIV Pune; Covaxin is the first vaccine in India to report safety and immunogenicity results from a booster clinical trial. A team of scientists led by Dr. Pragya Yadav, a Scientist at NIV Pune conducted the study on hamsters. They compared the protective efficacy of COVAXIN following 2 and 3-dose immunizations against the Delta variant.
They also studied the efficacy of COVAXIN against Omicron variants in a Syrian hamster model.
They also studied the efficacy of COVAXIN against Omicron variants in a Syrian hamster model. The antibody response, clinical observations, viral load reduction and lung disease severity after virus challenge were studied. The results also showed good cell-mediated response. Protective response in terms of the reduction in lung viral load and lung lesions were observed in both the second as well as a third dose of the Covaxin immunized group. When compared to the placebo group following the Delta variant challenge. In spite of the comparable neutralizing antibody response against the homologous vaccine strain in both the Dose 2 and Dose 3. Considerable reduction in the lung disease severity was observed in the third dose immunized group.
Post-Delta variant challenge, indicating the involvement of cell-mediated immune response also in protection. In the vaccine efficacy study against the Omicron variants BA.1 and BA.2, lesser virus shedding; lung viral load, and lung disease severity were observed in the immunized groups in comparison to the placebo groups. Booster dose vaccinations enhance the neutralizing antibody responses against homologous and heterologous variants.