Which of the following is an mRNA vaccine used against COVID-19 infection?

1. A

   Sinovac

   Option (a) claims Sinovac is an mRNA vaccine. However, Sinovac is an inactivated virus vaccine developed in China, not an mRNA platform.

2. B

   Moderna

   Option (b) claims Moderna is an mRNA vaccine used against COVID-19 infection. This is the correct answer because the Moderna Spikevax vaccine utilizes messenger RNA technology enclosed in lipid nanoparticles to instruct cells to produce the spike protein, triggering an immune response, and it stands as the official key among the choices provided.

3. C

   Sputnik

   Option (c) claims Sputnik is an mRNA vaccine. In reality, Sputnik V is a viral vector vaccine developed by the Gamaleya Research Institute in Russia, utilizing adenovirus vectors.

4. D

   Novavax

   Option (d) claims Novavax is an mRNA vaccine. Instead, Novavax is a protein subunit vaccine that delivers engineered spike proteins directly along with an adjuvant.

Summary. Official key is (b) Moderna. The question tests knowledge of different vaccine platforms deployed during the COVID-19 pandemic. Candidates often confuse viral vector or inactivated vaccines with newer mRNA technologies. Moderna, alongside Pfizer-BioNTech, famously relies on messenger RNA. Hence, only option (b) correctly identifies an mRNA vaccine.