In the context of vaccines manufactured to prevent COVID-19 pandemic, consider the following statements:

1. The Serum Institute of India produced COVID-19 vaccine named Covishield using mRNA platform.

2. Sputnik V vaccine is manufactured using vector based platform.

3. COVAXIN is an inactivated pathogen based vaccine.

Which of the statements given above are correct?

The correct option is 2 and 3 only.

Here is the step-by-step breakdown of why statements 2 and 3 are correct, while statement 1 is incorrect:

Statement 1 is incorrect:
Covishield was manufactured by the Serum Institute of India (under license from AstraZeneca and the University of Oxford). However, it is not an mRNA-based vaccine. Covishield is a viral vector vaccine that uses a weakened, modified chimpanzee adenovirus (ChAdOx1) to deliver the genetic code of the SARS-CoV-2 spike protein into human cells. In contrast, mRNA vaccines (like those developed by Pfizer-BioNTech and Moderna) use messenger RNA molecules wrapped in lipid nanoparticles to deliver genetic instructions.

Statement 2 is correct:
Sputnik V, developed by the Gamaleya Research Institute of Epidemiology and Microbiology in Russia, is manufactured using a viral vector-based platform. It utilizes two different human adenoviruses (Ad26 for the first dose and Ad5 for the second dose) as vectors to carry the gene for the SARS-CoV-2 spike protein into the body, triggering an immune response.

Statement 3 is correct:
COVAXIN, developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR) and the National Institute of Virology (NIV), is an inactivated pathogen-based vaccine. It uses dead (inactivated) SARS-CoV-2 viruses. Since the pathogen is inactivated, it cannot replicate or cause COVID-19, but it still trains the immune system to recognize and fight the live virus.

Therefore, statements 2 and 3 are correct, making "2 and 3 only" the correct answer choice.