A mixture: 1  can be separated into 2 or more substances by physical or mechanical means. 2  displays the properties of the pure substances making it up. 3  its composition can be varied by changing the proportion of pure substances making it up.  heterogeneous substances, ones with non-uniform composition throughout the sample, are always mixtures.
Injection Site Symptoms. At least half of all people who receive pneumonia shots will experience mild side effects in the area of injection, such as pain or redness. Less commonly, swelling or hardness may also occur in the area. These symptoms can limit movement of the arm or leg where the shot was given.
Vaccines, like any medicine, can have side effects. For most vaccines, serious side effects are extremely rare. The risks of vaccines are much lower than the risks of the diseases they prevent. Different vaccines have different side effects, most of which are mild. They include: 1  temporary pain.2  redness, swelling, or soreness where the shot was given.3  short-lived flu-like symptoms.he risks of vaccines are much lower than the risks of the diseases they prevent. Different vaccines have different side effects, most of which are mild. They include: 1  temporary pain. 2  redness, swelling, or soreness where the shot was given. 3  short-lived flu-like symptoms.