Emergency use proposal for Corbevax among kids: How is it different from other Covid vaccines?

With parts of India facing yet another surge in Covid cases, though so far subdued compared to earlier waves, the Subject Expert Committee of the Drugs Controller General of India has proposed emergency use of Corbevax vaccine for children between 5 and 12 years of age.

The same vaccine had earlier received emergency use authorisation for children between 12 and 18 years of age.

So how does Corbevax work?

Developed by Hyderabad-based Biological E, Corbevax is said to be India’s first indigenously developed Receptor-Binding Domain (RBD) protein sub-unit vaccine against Covid. RBD is that part of the spike protein of SARS-CoV-2 which attaches itself to the host cells after coming in contact with it.

Like other vaccines, Corbevax targets the spike protein, but instead of asking cells to replicate them, the vaccine injects lab-grown cloned spike proteins. The immune system feels threatened and develops a response, reducing the virus’s ability to infect the cells.

The vaccine has been developed in collaboration with Texas Children’s Hospital Centre for Vaccine Development and Baylor College of Medicine, Houston.

Biological E had earlier said that in its Phase-III human trials, Corbevax “demonstrated superior immune response in comparison with Covishield… against the ancestral Wuhan strain and the globally dominant Delta variant”. The vaccine had an effectiveness of over 90 per cent against the Wuhan strain and more than 80 per cent against the Delta variant. Reports said its effectiveness is being assessed against the Omicron variant.

Reports also say it could be the cheapest vaccine available in India with its two shots expected to be cumulatively priced at below Rs 400. The present cost of Corbevax for children between 12 and 14 years of age is Rs 145 at government facilities. Its two doses are administered 28 days apart. Covishield costs about Rs 300-400 for a single dose while Sputnik V costs around Rs 1,000. Covaxin costs about Rs 1,400 for its two doses.

Other countries are also gradually approving vaccines for children after due scrutiny. The United States has approved the Pfizer-BioNTech vaccine for children aged 5-17 years. The same vaccine has been granted permission in the United Kingdom for children aged 5-15 years. The EU’s European Medicines Agency has approved Moderna’s Spikevax vaccine for children aged 6-11 years.