A medical or religious exemption will allow an individual to decide against getting a vaccine, even if a health-related guideline would have otherwise mandated that the individual be vaccinated. Medical exemptions are usually granted to those who have an underlying health condition, such as a weakened immune system or autoimmune condition, or those who may experience a severe allergic reaction to a vaccine. A religious exemption may be granted to those who do not want to get vaccinated because of opposing religious beliefs.