Unlike allergy medicines , which act only to “cover up” allergic symptoms or prevent them temporarily, allergy shots fix the underlying problem of allergies . This occurs because the body treats the injection much like a vaccine, resulting in the production of infection-fighting antibodies against the pollen, dust, mold or pet dander . The body then stops producing as many allergic antibodies against the triggers, and therefore won’t have as much, or any, allergic response when exposed to the allergens. These changes can last for many years even after stopping allergy shots.
Most side effects and reactions to the flu shot are mild. Most commonly, people experience a soreness, redness, or mild swelling at the site where the shot was given. These effects generally do not last for more than 2 days. In rare cases, people may develop other mild reactions to the flu vaccine like fever and aches , which may mistakenly lead them to believe that they developed the flu as a result of the vaccine. These symptoms also go away after about 1 to 2 days. Because the flu shot contains inactivated, or killed, virus particles, there is no possibility of contracting the infection from the flu shot.