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.
Herd immunity is a form of indirect protection that applies only to contagious diseases. It occurs when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby reducing the likelihood of infection for individuals who lack immunity.
Immunization, or immunisation, is the process by which an individual's immune system becomes fortified against an infectious agent.
Influenza vaccines, colloquially known as flu shots, are vaccines that protect against infection by influenza viruses. New versions of the vaccines are developed twice a year, as the influenza virus rapidly changes. While their effectiveness varies from year to year, most provide modest to high protection against influenza. Vaccination against influenza began in the 1930s, with large-scale availability in the United States beginning in 1945.
An advance market commitment (AMC) is a promise to buy or subsidise a product if it is successfully developed. AMCs are typically offered by governments or private foundations to encourage the development of vaccines or treatments. In exchange, pharmaceutical companies commit to providing doses at a fixed price. This funding mechanism is used when the cost of research and development is too high to be worthwhile for the private sector without a guarantee of a certain quantity of purchases.
Vaccine hesitancy is a delay in acceptance, or refusal, of vaccines despite the availability of vaccine services and supporting evidence. The term covers refusals to vaccinate, delaying vaccines, accepting vaccines but remaining uncertain about their use, or using certain vaccines but not others. The scientific consensus that vaccines are generally safe and effective is overwhelming. Vaccine hesitancy often results in disease outbreaks and deaths from vaccine-preventable diseases. Therefore, the World Health Organization characterizes vaccine hesitancy as one of the top ten global health threats.
Pneumococcal polysaccharide vaccine, sold under the brand name Pneumovax 23, is a pneumococcal vaccine that is used for the prevention of pneumococcal disease caused by the 23 serotypes of Streptococcus pneumoniae contained in the vaccine as capsular polysaccharides. It is given by intramuscular or subcutaneous injection.
A vaccination schedule is a series of vaccinations, including the timing of all doses, which may be either recommended or compulsory, depending on the country of residence. A vaccine is an antigenic preparation used to produce active immunity to a disease, in order to prevent or reduce the effects of infection by any natural or "wild" pathogen. Vaccines go through multiple phases of trials to ensure safety and effectiveness.
Artificial induction of immunity is immunization achieved by human efforts in preventive healthcare, as opposed to natural immunity as produced by organisms' immune systems. It makes people immune to specific diseases by means other than waiting for them to catch the disease. The purpose is to reduce the risk of death and suffering, that is, the disease burden, even when eradication of the disease is not possible. Vaccination is the chief type of such immunization, greatly reducing the burden of vaccine-preventable diseases.
Pneumococcal conjugate vaccine is a pneumococcal vaccine made with the conjugate vaccine method and used to protect infants, young children, and adults against disease caused by the bacterium Streptococcus pneumoniae (pneumococcus). It contains purified capsular polysaccharide of pneumococcal serotypes conjugated to a carrier protein to improve antibody response compared to the pneumococcal polysaccharide vaccine. The World Health Organization (WHO) recommends the use of the conjugate vaccine in routine immunizations given to children.
Varicella vaccine, also known as chickenpox vaccine, is a vaccine that protects against chickenpox. One dose of vaccine prevents 95% of moderate disease and 100% of severe disease. Two doses of vaccine are more effective than one. If given to those who are not immune within five days of exposure to chickenpox it prevents most cases of disease. Vaccinating a large portion of the population also protects those who are not vaccinated. It is given by injection just under the skin. Another vaccine, known as zoster vaccine, is used to prevent diseases caused by the same virus – the varicella zoster virus.
Pneumococcal vaccines are vaccines against the bacterium Streptococcus pneumoniae. Their use can prevent some cases of pneumonia, meningitis, and sepsis. There are two types of pneumococcal vaccines: conjugate vaccines and polysaccharide vaccines. They are given by injection either into a muscle or just under the skin.
Immunization during pregnancy is the administration of a vaccine to a pregnant individual. This may be done either to protect the individual from disease or to induce an antibody response, such that the antibodies cross the placenta and provide passive immunity to the infant after birth. In many countries, including the US, Canada, UK, Australia and New Zealand, vaccination against influenza, COVID-19 and whooping cough is routinely offered during pregnancy.
Ciro Carlos Araujo de Quadros was a Brazilian leader in the field of Public Health, in particular, the area of vaccines and preventable diseases. He was born in Rio Pardo, Brazil.
Claims of a link between the MMR vaccine and autism have been extensively investigated and found to be false. The link was first suggested in the early 1990s and came to public notice largely as a result of the 1998 Lancet MMR autism fraud, characterised as "perhaps the most damaging medical hoax of the last 100 years". The fraudulent research paper, authored by discredited former doctor Andrew Wakefield and published in The Lancet, falsely claimed the vaccine was linked to colitis and autism spectrum disorders. The paper was retracted in 2010 but is still cited by anti-vaccine activists.
A vaccination policy is a health policy adopted in order to prevent the spread of infectious disease. These policies are generally put into place by state or local governments, but may also be set by private facilities, such as workplaces or schools. Many policies have been developed and implemented since vaccines were first made widely available.
Universal Immunisation Programme (UIP) is a vaccination programme launched by the Government of India in 1985. It became a part of Child Survival and Safe Motherhood Programme in 1992 and is currently one of the key areas under the National Health Mission since 2005. The programme now consists of vaccination for 12 diseases- tuberculosis, diphtheria, pertussis, tetanus, poliomyelitis, measles, hepatitis B, rotaviral gastroenteritis, Japanese encephalitis, rubella, pneumonia and Pneumococcal diseases. Hepatitis B and Pneumococcal diseases were added to the UIP in 2007 and 2017 respectively. The cost of all the vaccines are borne entirely by the Government of India and is funded through taxes with a budget of ₹7,234 crore (US$910 million) in 2022 and the program covers all residents of India, including foreign residents.
GAVI, officially Gavi, the Vaccine Alliance is a public–private global health partnership with the goal of increasing access to immunization in poor countries. In 2016, Gavi channeled more than half of total donor assistance for health, and most donor assistance for immunization, by monetary measure.
Helen Aspasia Petousis-Harris is a New Zealand vaccinologist and associate professor in the Department of General Practice and Primary Health Care at the University of Auckland. She has been involved in research related to vaccination in New Zealand since 1998, with her main areas of focus being vaccine safety and effectiveness. Petousis-Harris has had a variety of lead roles in New Zealand and international organisations that focus on vaccination and is a regular media spokesperson in this field, especially during the COVID-19 pandemic.
Shabir Ahmed Madhi, is a South African physician who is professor of vaccinology and director of the South African Medical Research Council Respiratory and Meningeal Pathogens Research Unit at the University of the Witwatersrand, and National Research Foundation/Department of Science and Technology Research Chair in Vaccine Preventable Diseases. In January 2021, he was appointed Dean of the Faculty of Health Sciences at the University of the Witwatersrand.
