Covaxin against Delta

Covaxin against Delta

Subject: Science and Technology

Context: While the Delta variant mutated into ‘Delta Plus’, first detected in India in April 2021, researchers decided to study the efficacy of the Covaxin vaccine.

Concept:

• Covaxin has been developed by Bharat Biotech and the Indian Council of Medical Research (ICMR).
• The research study showed that Covaxin vaccine could still neutralise Delta, AY.1 and B.1.617.3 variants
• In a previous study, Covaxin had demonstrated 77.8% effectiveness against symptomatic Covid-19 and 65.2% protection against the Delta variant, according to Bharat Biotech.
• In this new study, despite the sera of vaccinated Covid-recovered cases and those of breakthrough cases showing considerable reduction in the neutralisation antibody titre.

Antibody titre

An antibody titer is a type of blood test that determines the presence and level (titer) of antibodies in the blood. This test is carried out to investigate if there is an immune reaction triggered by foreign invaders (antigens) in the body.

About Delta Plus variant

• So far, no information was available on the efficacy of currently available vaccines against the Delta Plus variant.
• The possibility of the variant escaping the immune response has been a major concern during the ongoing vaccination programme.
• This variant contains an additional mutation (K417N ) in the spike protein and emerging evidence suggests that this mutation could lead to resistance against monoclonal antibodies called casirivimab and imdevimab.