Vaccines are a common method of heading off deadly diseases. The trick in developing a vaccine is finding a weaker form of the disease that can trigger an immune response, so that when the real disease shows up, the immune system is locked and loaded for it. The word vaccine flows from the Latin vacca for cow.

The original vaccine was for smallpox; when a British scientist found that milk maid weren’t getting smallpox, he found that cowpox, a much milder illness, gave them immunity to smallpox. They then proceeded to deliver the cowpox virus to folks, fending off the now-extinct (other than lab samples) smallpox virus.

One modern method finds an attenuated (weakened) version of a virus, one that will trigger an immune response to the virus but won’t wreck havoc on the body of the person getting vaccinated. That takes time, for the virus first has to be identified and then a crippled version of the virus will need to be created.

A second route is to kill the viruses and then inject them. Such killed viruses are safer for a lot of high-risk groups, like children under 2, the elderly and folks with immune-deficiencies.

The nasal-spray version of the vaccine is a live virus version, so at-risk folks or people who live with them should avoid it and get the killed-virus shot version.

Vaccines can cause reactions in people, so people are often leery of them. However, most vaccines are well-tested before given to a broad population and the side-effects will be far less than the effects of the virus, else it won’t be given. That hasn’t kept health care workers in New York from protesting having to get the vaccine.

However, it won’t help if you already have the flu ; one student of mine noted that she had scheduled a flu shot for a week from now and then proceeded to catch the flu.