Overview of immunization

[GarryDrold]

Immunization enables the body to better defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by certain bacteria or viruses) may occur naturally (when people are exposed to bacteria or viruses), or doctors may provide it through vaccination. When people are immunized against a disease, they usually do not get the disease or get only a mild form of the disease. However, because no vaccine is 100% effective, some people who have been immunized still may get the disease.
In communities and countries where vaccines are widely used, many diseases that were once common and/or fatal (such as polio and diphtheria) are now rare or under control. One disease, smallpox, has been completely eliminated by vaccination. Vaccines have been very effective in preventing serious disease and in improving health worldwide. However, effective vaccines are not yet available for many important infections, including Ebola virus infection, most sexually transmitted diseases (such as HIV infection, syphilis, gonorrhea, and chlamydial infections), and many tropical diseases (such as malaria).
Following recommendations for vaccination is very important for people

[Merna]

Immunity can be achieved

Actively by using antigens (eg, vaccines, toxoids)
Passively by using antibodies (eg, immune globulins, antitoxins)

A toxoid is a bacterial toxin that has been modified to be nontoxic but that can still stimulate antibody formation.
A vaccine is a suspension of whole (live or inactivated) or fractionated bacteria or viruses rendered nonpathogenic. For vaccines available in the US, see Table: Vaccines Available in the US.
The most current recommendations for immunization are available at the Centers for Disease Control and Prevention (CDC) web site and as a free mobile app. Also see Table: Vaccine Administration Guidelines for Adults, see Table: Recommended Immunization Schedule for Ages 7–18 Years (see also the CDC#39;s Recommended Child and Adolescent Immunization Schedule), and see Table: Vaccine Administration Guidelines for Adults (see also the CDC#39;s Recommended Adult Immunization Schedule).
For the contents of each vaccine (including additives), see that vaccine#39;s package insert.
Vaccination has been extremely effective in preventing serious disease and in improving health worldwide. Because of vaccines, infections that were once very common and/or fatal (eg, smallpox, polio, diphtheria) are now rare or have been eliminated. However, except for smallpox, these infections still occur in parts of the developing world.
Effective vaccines are not yet available for many important infections, including

Most sexually transmitted diseases (eg, HIV infection, herpes, syphilis, gonorrhea, chlamydial infections)
Tick-borne infections (eg, Lyme disease, ehrlichiosis and anaplasmosis, babesiosis)
Many tropical diseases (eg, malaria, Chikungunya disease, dengue)
Emerging diseases (eg, coronavirus infections such as COVID-19, West Nile virus infection)

Certain vaccines are recommended routinely for all adults at certain ages who have not previously been vaccinated or have no evidence of previous infection. Other vaccines (eg, rabies, bacille Calmette-Gu#233;rin, typhoid, yellow fever) are not routinely given but are recommended only for specific people and circumstances (see the CDC#39;s Recommended Adult Immunization Schedule and under the specific disorder, elsewhere in THE MANUAL; 1).
Some adults do not get the vaccines recommended for them. For example, only 55.1% of those gt; 65 were given a tetanus vaccine within a 10-year period. Also, vaccination rates tend to be lower in blacks, Asians, and Hispanics than in whites.
(See also PATH#39;s Vaccine Resource Library.)