Coronaviruses are a group of viuses that include both the common cold and the flu, and a number of other viruses that cause upper- and lower-respiratory tract infections, such as SARS and MERS in past years. They affect many different species of animals as well as humans. Although they usually stick to a single species, they sometimes jump from one to another, such as when the bird flu jumped from birds to humans. Coronaviruses can cause a very mild disease, or they may cause a more severe disease which can even lead to death. It is very difficult to create a vaccine against coronaviruses, because they mutate fairly rapidly into forms which are not affected by the vaccine. The flu vaccine is developed every year aginst the one or two most common strains of the flu going around that flu season. That is why you have to get a new flu vaccine every year - by the time flu season rolls around the next year, the strains of flu that last year's vaccine protected against have died out and new strains are active and require a new vaccine. If you do get the flu vaccine every year, you are mostly protected against those strains, but you can still catch a different strain of flu. Nothing is perfect.
With regard to the novel coronavirus out of China, they may or may not develop a vaccine before it mutates into a new strain, like flu. The new strain may be as virulent at the old strain, or it may be less, like a bad cold. There is no way to predict that. I have not heard whether they are using antivirals against it, or even if antivirals are effective against it. Apparently, the most effective measures at this time are not to travel to China, and not to come in contact with anyone who has traveled to China Since December.
Although thinking about "weoponized viruses" with regard to the coronavirus may be considered, I seriously doubt it could be done - coronaviruses are too unstable to make that possible. Some other virus, possibly, but not coronavirus.