The likelihood that allergic rhinitis or asthma will spontaneously go away is approximately 1% per year. That means medications usually will be needed for many years. The main advantage of allergy vaccines is that they greatly diminish the severity of a person’s allergic reactions, reducing the need for medications while further reducing symptoms. The disadvantages of allergy vaccine are that several injections are needed to build up to the monthly maintenance injections, and the person might have an allergic reaction to an injection. Many people would rather have monthly injections for 3 years than take medications for an indefinite period of time.