Vaccination is a preventive measure. It’s a so-called “vaccination”.
When a foreign object such as a pathogen invades the human body, the immune system works to break it apart. Immunity is able to remember the characteristics of an invaded opponent once it has been invaded. Therefore, the second time they invade, immunity works quickly to defeat the pathogen quickly before it can multiply in large numbers. This is called “acquired immunity”.
Vaccines take advantage of the nature of acquired immunity. Injecting a pre-detonated or weakened virus to make immunity remember the characteristics of the virus. That way, when a real virus comes in, you can respond quickly.
Recently, not only detoxified viruses, but also virus components and even RNA injections to produce these components have been developed in Japan and abroad. This is thanks to advances in science that allow us to handle publicly available genetic data without the virus itself being at hand.
Clinical trials to confirm the safety and efficacy of vaccines for new coronaviruses are being conducted overseas, but it will take quite some time to confirm whether they are really effective. Under these circumstances, the speed of approval from the authorities may be accelerated, but it is still expected to take a year and a half to two years, no matter how successful, from the start of clinical trials to commercialization.