Demystifying The Jungle Of Covid-19 Vaccines

What really is the best vaccine out there?

- Dr. Edsel Maurice T. Salvana

The global push for safe and effective vaccines against Covid-19 has led to a bum-per crop of vaccine candidates. With over 200 Covid-19 vaccines in development and at least 10 vaccines completing or about to complete phase 3 clinical trials, which vaccine is the best?

In last week’s column, I emphasized that for those in imminent danger of severe Covid-19 should get vaccinated as soon as possible with whatever properly approved vaccine is available. This will be the case in the short term as global demand outstrips supply. As supply chains catch up and more vaccines are proven to work, we will get to the point where we can choose the most appropriate vaccine for each of us.

Covid-19 vaccines fall under one of six categories. These are the categories.

a. Nucleic acid-based vaccines use viral genetic material, whether RNA or DNA. This includes the mRNA vaccines like Pfizer and Moderna.

b. Inactivated virus vaccines use killed whole virus. This vaccine type includes Sinovac and Sinopharm vaccines.

c. Recombinant viral vectored vaccines use a harmless live virus as a carrier for the target virus’ genetic material to induce an immune response. Current Covid-19 vaccines using this technology use live but non-replicating carrier viruses like adenovirus 5 or adenovirus 26. Examples are vaccines from Astra, Cansino, J&J, and Gamaleya.

d. Protein subunit vaccines use a piece of the virus, usually the spike protein, to generate an immune response.

e. Virus-like particle vaccines use artificial construct or structure that mimics real viruses and the body’s immune system responds accordingly.

f. Live attenuated virus vaccines use a weakened form of the target virus to induce the immune response.