Vaccines for other viruses don't work for coronavirus. Vaccines work by boosting the person's own immune response against inactivated viral antigens that we introduce in his body through the vaccines. These antigens are highly specific. Newly formed viruses carry new antigens that the body does not recognize that we need to identify and isolate first in order to develop a vaccine for this new virus. Then we will need some time to test the vaccines. These testings will get a fast-track designation, but still they will need some months to develop.
During the years we have developed several novel anti-viral drugs (to combat diseases like AIDS, hepatitis C, influenza, etc). Some of them are irrelevant for coronavirus, such as Tamiflu, which is directed against an enzyme uniquely found in influenza viruses but not in coronaviruses. Some others theoretically could be useful against coronavirus. However, we cannot do medicine with anecdotes of 1 or 2 people being healed or improved after the use of some antivirals. Especially when we deal with diseases like viral diseases, where most people will improve without treatment anyway (Its funny how some people still think that one or two pills of antibiotics was the reason why a flu they once had, quickly subsided). We need to test all these drugs in credible and controlled studies before we claim that they trully carry activity against coronavirus.
A person that has been infected by a virus, carries antibodies and memory cells in his blood plasma, able to recognize and fight a reinfection. This is not something new or unexpected. This is how vaccines were discovered in the first place. However, the general application of this method to the entire population in the case of a pandemy is highly controversial at best and the challenges are huge.