Child Immunization Services

Babies are born with protection against several diseases because their mothers pass antibodies (proteins made by the body to fight disease) to them before birth. Babies who are breastfed growing up are continuously getting antibodies from the breast milk. But in both cases, the protection is temporary.

Immunization (vaccination) is a way to create immunity to (protection from) some diseases. Sometimes this is done by using small amounts of a killed or weakened germ that causes the disease. Other times the vaccine is simply a small piece of the germ, such as a protein or a piece of its genetic material.

Germs can be viruses (such as the measles virus) or bacteria (such as pneumococcus). Vaccines stimulate the immune system to react as if there were a real infection. It fends off the "infection" and remembers the germ. Then, it can fight the germ if it enters the body later.

There are a few different types of vaccines:

- Attenuated (weakened) live germs: These are used in some vaccines such as in the measles, mumps, and rubella (MMR) and chickenpox vaccines.
- Killed (inactivated) germs: These are used in some vaccines, such as in the flu shot or the inactivated poliovirus vaccine.
- Toxoid vaccines: These contain an inactivated toxin (harmful chemical) made by the germ. For example, the diphtheria and tetanus vaccines are toxoid vaccines.
- Conjugate vaccines: These contain small pieces of the germ combined with proteins that help trigger a strong immune response. Many commonly used vaccines are made this way, including those that protect against hepatitis B, HPV, whooping cough, and meningitis.
- mRNA (messenger RNA) vaccines: These use a piece of the germ’s RNA, which is part of its genetic material. Some of the COVID-19 vaccines are this type