Question

You have been tasked with developing a new passive vaccine for the novel coronavirus. Describe your vaccine development strategy and why you chose it.

Answer 1

• The fast-spreading COVID-19 has already infected almost half a million worldwide, and has killed over 22,000 patients. There is an urgent need for a vaccine to prevent it from infecting and killing millions more. But traditional vaccine development takes, on average, 16 years.

• coronovirus enters into the lung and possibly other respiratory track cells by attaching through to them via its spike protein. Once inside, the viral RNA becomes part of the host cell’s protein production machinery, and produces new copies of viral proteins and RNA which then assemble into thousands of new viruses to spread the disease.

  So one way to stop a disease is to block the virus from entering the cells. Vaccines do that by training the body to identify and attack the virus before it can infect healthy human cells.

  A vaccine is essentially a pure preparation of one or more key components of the virus – such as the envelope, spike or a membrane protein – that is injected in the body to give the immune system a preview of the virus without causing disease. This preview tells the immune system to seek out and attack the virus containing those specific proteins if the real virus ever shows up.

  However, developing vaccines based on viral proteins takes anywhere from years, such as for the human papilloma virus, to several decades, such as for rotavirus. Protein-based vaccines require mass production of viral proteins in facilities which can guarantee their purity. Growing the viruses and purifying the proteins at medically acceptable pharmaceutical scales can take years.

• To make an effective vaccine more quickly against never-before-seen, fast-spreading viruses such as SARS-CoV-2, researchers at Vanderbilt and elsewhere are using alternate approaches. In one approach, instead of proteins, a new generation of vaccines, called mRNA vaccines, will carry the molecular instructions to make the protein.

  Instead of the standard vaccines where viral proteins are used to immunize, an mRNA vaccine provides a synthetic mRNA of the virus, which the host body then uses to produce the viral proteins itself.

  The biggest advantage of the mRNA vaccines is that they can bypass the hassle of producing pure viral proteins, sometimes saving months or years to standardize and ramp up the mass production.

  The mRNA vaccines basically mimic the natural infection of the virus, but they contain only a short synthetic version of the viral mRNA which encodes only the antigen protein. Since the mRNA used in vaccination cannot become part of the person’s chromosomes, they are safe to use. Such mRNA vaccines would also be safer than the weakened viral or protein-based vaccines because they do not carry the risk of the injected virus becoming active, or a protein contamination.