Inactivated vaccine

Inactivated vaccine
Typhoid prophylaxis for soldiers in World War I.
Other names	Killed vaccine
Specialty	Public health, Immunology, Family medicine, General practice
Uses	prevention of infectious diseases
Frequency	birth to adulthood See also: Vaccination schedule and Vaccination policy § By country
Outcomes	development of active immunity in individuals; contribution to herd immunity
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An inactivated vaccine (or killed vaccine) is a vaccine consisting of virus particles, bacteria, or other pathogens that have been grown in culture and then killed to destroy disease-producing capacity. In contrast, live vaccines use pathogens that are still alive (but are almost always attenuated, that is, weakened). Pathogens for inactivated vaccines are grown under controlled conditions and are killed as a means to reduce infectivity and thus prevent infection from the vaccine.^[1]

Inactivated vaccines were first developed in the late 1800s and early 1900s for cholera, plague, and typhoid.^[2] Today, inactivated vaccines exist for many pathogens, including influenza, polio (IPV), rabies, hepatitis A and pertussis.^[3]

Because inactivated pathogens tend to produce a weaker response by the immune system than live pathogens, immunologic adjuvants and multiple "booster" injections may be required in some vaccines to provide an effective immune response against the pathogen.^[1][4][5] Attenuated vaccines are often preferable for generally healthy people because a single dose is often safe and very effective. However, some people cannot take attenuated vaccines because the pathogen poses too much risk for them (for example, elderly people or people with immunodeficiency). For those patients, an inactivated vaccine can provide protection.^{[citation needed]}