Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating the body's adaptive immunity, they help prevent sickness from an infectious disease. When a sufficiently large percentage of a population has been vaccinated, herd immunity results. Herd immunity protects those who may be immunocompromised and cannot get a vaccine because even a weakened version would harm them. The effectiveness of vaccination has been widely studied and verified. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio and tetanus from much of the world. However, some diseases, such as measles outbreaks in America, have seen rising cases due to relatively low vaccination rates in the 2010s – attributed, in part, to vaccine hesitancy. According to the World Health Organization, vaccination prevents 3.5–5 million deaths per year.
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future.
This is a timeline of the development of prophylactic human vaccines. Early vaccines may be listed by the first year of development or testing, but later entries usually show the year the vaccine finished trials and became available on the market. Although vaccines exist for the diseases listed below, only smallpox has been eliminated worldwide. The other vaccine-preventable illnesses continue to cause millions of deaths each year. Currently, polio and measles are the targets of active worldwide eradication campaigns.
Stanley Alan Plotkin is an American physician who works as a consultant to vaccine manufacturers, such as Sanofi Pasteur, as well as biotechnology firms, non-profits and governments. In the 1960s, he played a pivotal role in discovery of a vaccine against rubella virus while working at Wistar Institute in Philadelphia. Plotkin was a member of Wistar’s active research faculty from 1960 to 1991. Today, in addition to his emeritus appointment at Wistar, he is emeritus professor of Pediatrics at the University of Pennsylvania. His book, Vaccines, is the standard reference on the subject. He is an editor with Clinical and Vaccine Immunology, which is published by the American Society for Microbiology in Washington, D.C.
Jules Freund was a Hungarian born American immunologist, most famous for the Freund's adjuvant.
Paul Allan Offit is an American pediatrician specializing in infectious diseases, vaccines, immunology, and virology. He is the co-inventor of a rotavirus vaccine. Offit is the Maurice R. Hilleman Professor of Vaccinology, professor of pediatrics at the Perelman School of Medicine at the University of Pennsylvania, former chief of the Division of Infectious Diseases (1992–2014), and the director of the Vaccine Education Center at the Children's Hospital of Philadelphia.
Neal A. Halsey is an American pediatrician, with sub-specialty training in infectious diseases, international health and epidemiology. Halsey is a professor emeritus of international health and director emeritus of the Institute for Vaccine Safety at the Johns Hopkins Bloomberg School of Public Health, in Baltimore, Maryland. He had a joint appointment in the Department of Pediatrics at the Johns Hopkins School of Medicine and serves as co-director of the Center for Disease Studies and Control in Guatemala.
William Herbert Foege is an American physician and epidemiologist who is credited with "devising the global strategy that led to the eradication of smallpox in the late 1970s". From May 1977 to 1983, Foege served as the Director of the Centers for Disease Control and Prevention.
An attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable. Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by "killing" the pathogen.
Hepatitis B vaccine is a vaccine that prevents hepatitis B. The first dose is recommended within 24 hours of birth with either two or three more doses given after that. This includes those with poor immune function such as from HIV/AIDS and those born premature. It is also recommended that health-care workers be vaccinated. In healthy people, routine immunization results in more than 95% of people being protected.
The Haemophilus influenzae type B vaccine, also known as Hib vaccine, is a vaccine used to prevent Haemophilus influenzae type b (Hib) infection. In countries that include it as a routine vaccine, rates of severe Hib infections have decreased more than 90%. It has therefore resulted in a decrease in the rate of meningitis, pneumonia, and epiglottitis.
The rotavirus vaccine is a vaccine used to protect against rotavirus infections, which are the leading cause of severe diarrhea among young children. The vaccines prevent 15–34% of severe diarrhea in the developing world and 37–96% of the risk of death among young children due to severe diarrhea. Immunizing babies decreases rates of disease among older people and those who have not been immunized.
Rubella vaccine is a vaccine used to prevent rubella. Effectiveness begins about two weeks after a single dose and around 95% of people become immune. Countries with high rates of immunization no longer see cases of rubella or congenital rubella syndrome. When there is a low level of childhood immunization in a population it is possible for rates of congenital rubella to increase as more women make it to child-bearing age without either vaccination or exposure to the disease. Therefore, it is important for more than 80% of people to be vaccinated. By introducing rubella containing vaccines, rubella has been eradicated in 81 nations, as of mid-2020.
An inactivated 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. 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.
Katherine "Kate" L. O'Brien is a Canadian American pediatric infectious disease physician, epidemiologist, and vaccinologist who specializes in the areas of pneumococcal epidemiology, pneumococcal vaccine trials and impact studies, and surveillance for pneumococcal disease. She is also known as an expert in infectious diseases in American Indian populations. O’Brien is currently the Director of the World Health Organization's Department of Immunization, Vaccines and Biologicals.
Frank DeStefano FACPM is a medical epidemiologist and researcher at the Centers for Disease Control and Prevention, where he is director of the Immunization Safety Office.
An alternative vaccination schedule is a vaccination schedule differing from the schedule endorsed by the Advisory Committee on Immunization Practices (ACIP). These schedules may be either written or ad hoc, and have not been tested for their safety or efficacy. Proponents of such schedules aim to reduce the risk of adverse effects they believe to be caused by vaccine components, such as "immune system overload" that is argued to be caused by exposure to multiple antigens. Parents who adopt these schedules tend to do so because they are concerned about the potential risks of vaccination, rather than because they are unaware of the significance of vaccination's benefits. Delayed vaccination schedules have been shown to lead to an increase in breakthrough infections without any benefit in lower side effect profiles.
Rabies immunoglobulin (RIG) is a medication made up of antibodies against the rabies virus. It is used to prevent rabies following exposure. It is given after the wound is cleaned with soap and water or povidone-iodine and is followed by a course of rabies vaccine. It is given by injection into the site of the wound and into a muscle. It is not needed in people who have been previously vaccinated against rabies.
Arnold Monto is an American physician and epidemiologist. At the University of Michigan School of Public Health, Monto is the Thomas Francis Jr. Collegiate Professor of Public Health, professor of epidemiology, and professor of global public health. His research focuses on the occurrence, prevention, and treatment of infectious diseases in industrialized and developing countries' populations.
