Vaccine is a way to protect yourself and others from serious infectious diseases. These illnesses can make you very sick, cause long-lasting or life-threatening complications, and even be deadly. Vaccines are safe and very effective.
Almost all vaccines contain weakened or killed forms of viruses and bacteria, called antigens, which stimulate the immune system to create antibodies against the germs without making you sick. The immune system then remembers these antibodies, and can quickly make more when you come in contact with the germ again.
Most vaccines also contain adjuvants, which help the body respond to the antigens. Adjuvants may include aluminum salts or thimerosal, and stabilizers like gelatin. Some vaccines use genetic material to get the antigen into the cell, such as mRNA or viral vectors. These vaccines are sometimes called recombinant or synthetic vaccines.
Many people worry that vaccines might make them sick or might give them the disease they prevent. However, the germs in vaccines are weakened or killed and only small amounts of the virus or bacteria are used. In addition, most vaccines do not cause any significant side effects, and most severe reactions to vaccines are rare.
Vaccines reduce the number of people who get sick with an infectious disease, and they reduce how far the infection spreads in a community. Vaccines can help save lives by preventing disease outbreaks that would otherwise overwhelm hospitals and other treatment facilities. Vaccines also help protect the health of people who need care in hospital, including babies who might be too young to receive their first dose of vaccine or who are too old for a particular vaccine.