Vaccines are dummies that work by tricking your immune system into thinking that it’s being attacked by a virus. The immune system then churns out antibodies that are honed to that virus. That way, if someone is exposed to that virus in the future, the body can quickly squash it out before it makes them sick. Triggering such immune response takes two main components: a bit of the virus so the body knows what it’s looking for and some kind of irritant to stir the immune system into action against that viral bit. If someone just put purified protein under your skin, nothing would happen. You have to get the immune system kicked up that’s where irritants come into play. Some basic approaches scientists are throwing at the virus are:
- GENE-BASED VACCINES- Gene-based vaccines are the much-hyped underdog in the race to create a coronavirus vaccine. Most of the vaccine candidates that grabbed headlines or sent the stock market soaring are gene-based. Gene-based vaccines instead of directly delivering bits of the virus to the immune system for target practice, give the body tools to make them on its own. The vaccines are made up of pieces of genetic material, either mRNA or DNA, that encode the instructions for making the protein which when enters cells, read the instructions and churn out copies of the protein for the immune system to rally against. These types of vaccines are relatively easy for companies to make once they know the genetic sequence they’re targeting But despite their simplicity and decades of work, gene-based viruses are still largely experimental, at least for people. Moderna and Pfizer have gene based vaccine.
- INACTIVATED VIRUS- Scientists take a virus and kill it with heat or radiation thereby rendering it harmless, but still recognizable by the immune system. A handful of Chinese companies are developing coronavirus vaccines using this method. One company, Sinovac, showed that its vaccine could protect monkeys from COVID-19. Human trials are ongoing. Because these types of vaccines have been around for decades, therefore scientists understand them well. Because these vaccines contain the whole (but non-replicating) virus, they’re good irritants for the immune system. Unlike gene-based vaccines, though, inactivated virus vaccines are hard to make. Manufacturers have experience with them, but they have to grow and then zap massive amounts of virus. Therefore it’s a slow process.
- ADENOVIRUS VECTOR VACCINES- A whole, live vaccine is one of the best ways to create long-lasting immunity. That’s the strategy used to make vaccines for the measles and the chickenpox. They’re made from live but heavily weakened versions of the viruses. The viruses are so weak that they don’t make you sick, but they still make your body think it’s infected and set off the immune system. But it takes a long time to alter a virus so that it becomes weak and safe enough to be used as a vaccine, therefore to speed things up, vaccine developers aren’t even attempting to do that with the entire coronavirus. Instead, some teams are inserting sections of the coronavirus gene into weakened, live versions of other viruses. These viruses are called adenoviruses, Because this vaccine is based on a weakened, but a living virus, the immune system mounts a strong response against it. Even though live virus vaccines are regularly used, the adenovirus platforms are still experimental. Also, some people might have seen the adenovirus before so the vaccine wouldn’t work for them. University of Oxford is working on Adenovirus vector.
- PROTEIN SUBUNIT VACCINES- Protein subunit vaccines directly deliver the specific bit of the virus scientists want people to develop antibodies against (rather than the gene for the protein). For the coronavirus, in most cases, that’s the spike protein. These vaccines contain copies of the spike protein and a bit of something to stimulate the immune system. Scientists are familiar with this approach, and it’s worked well for other diseases. Because these vaccines only use a piece of a virus, they sometimes aren’t able to push the body to generate a strong enough immune response, even with a good irritant built-in. Therefore people often need multiple shots to build up enough immunity to the disease which is a challenge during this pandemic. Because creating enough vaccines to give each person one-shot is already a challenge.
There’s a long history in vaccinology of trying multiple approaches to the same end goal because no one knows which strategy or which vaccine candidate will work best. You can’t speed that the process of testing vaccines. Because tests have to be conducted on a large group of people and researchers have to wait to see if someone actually develops immunity to disease after they’re given a trial vaccine They also have to watch for any safety concerns, either short-term side effects or long term. Speeding up the authorization process of a vaccine is a dangerous task because there are no guinea pigs to experiment on. It is a gamble with too much on stake. Rather we should cross our fingers and hope for the best.