As COVID-19 continues to spread throughout the world, scientists have worked against the clock to produce a safe and effective vaccine. These vaccines can largely be separated into 3 major categories.
- Inactivated vaccines
- Viral Vector based vaccines
- Molecule-based vaccines
The China-based biopharmaceutical company Sinovac has developed an inactivated vaccine called CoronaVac. This vaccine contains a killed version of the virus, which the patient’s immune system can recognize and launch an appropriate response. One such response is the production of antibodies, large biomolecule complexes that bind to the antigens (molecules of the invaders) and mark them for destruction. In phase i-ii trials, CoronaVac has shown 90%+ seroconversion rates in adults and elderly populations. This means that detectable amounts of anti-COVID antibodies are present in more that 90% of the subjects who are given the vaccine. Additionally, CoronaVac has shown little to no side effects. CoronaVac has shown itself to be safe and effective.
CanSino, another Chinese biopharma company has developed Ad5-nCoV, an adenovirus vector based vaccine. This vaccine contains a gene that codes for the coronavirus spike protein. This gene is placed inside of a strain of adenovirus incapable of replication. When administered, the adenovirus makes its way into a cell, and releases the gene for expression. The resulting synthesis of the coronavirus spike protein elicits an immune response. The body generates antibodies that tag onto the spike protein. This means that if the patient is infected with COVID-19, the antibodies immediately bind to the virus’ spike proteins, squashing the infection quickly. The vaccine showed seroconversion rates above 90%, and has shown little side effects. Ad5-nCoV has shown itself to be safe and effective.
Lastly there is the America-based NovaVax’s NVAX-CoV2373, a nanoparticle based vaccine. The coronavirus spike protein is placed in a nanoparticle in which its arrangement is similar to the spike protein’s arrangement in the actual virus. This is the immunogenic particle. In addition to this, the Matrix-M nanoparticle induces a strong immune response against the vaccine, therefore stimulating long-term immunity. The vaccine has shown promising results, as the immune response is strong, and the Matrix-M nanoparticle stimulates the correct parts of the immune system. It has shown itself to be safe and effective.
Without a vaccine, our control of the virus is limited to lockdowns and contact tracing. Mass testing is key to the control of the virus, as we can then use this data to protect those with and without the virus. These methods are all designed to mitigate the effects of the virus.
On the other hand, vaccines give us something to push against the virus. Control of the virus with a vaccine is not easy though, and should not be seen as a “the end of COVID”. The vaccine gives us an advantage through.
As of the writing of this article, there are 7 vaccines in phase 3 clinical trials. At this phase, larger scale human trials are conducted. Many of these vaccines have shown promise in earlier phases, but our good practices cannot stop now. Despite the fast tracking that these vaccines have received, they are not perfect. Wear a mask, keep your distance, wash your hands and avoid large crowds. It is only through a combination of quarantining, vaccination and good practices, can COVID-19 be made extinct.