Vaccination is the administration of a vaccine
to help the immune system
develop protection 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
and the elimination of diseases such as polio
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
The first disease people tried to prevent by inoculation
was most likely smallpox, with the first recorded use of variolation
occurring in the 16th century in China
. It was also the first disease for which a vaccine was produced.
Although at least six people had used the same principles years earlier, the smallpox vaccine
was invented in 1796 by English physician Edward Jenner
. He was the first to publish evidence that it was effective and to provide advice on its production.
furthered the concept through his work in microbiology. The immunization was called ''vaccination'' because it was derived from a virus affecting cow
s ( la|vacca 'cow').
Smallpox was a contagious and deadly disease, causing the deaths of 20–60% of infected adults and over 80% of infected children. When smallpox was finally eradicated in 1979, it had already killed an estimated 300–500 million people in the 20th century.
''Vaccination'' and ''immunization'' have a similar meaning in everyday language. This is distinct from inoculation, which uses unweakened live pathogens. Vaccination efforts have been met with some reluctance
on scientific, ethical, political, medical safety, and religious grounds, although no major religions oppose vaccination, and some consider it an obligation due to the potential to save lives.
In the United States, people may receive compensation for alleged injuries under the National Vaccine Injury Compensation Program
. Early success brought widespread acceptance, and mass vaccination campaigns have greatly reduced the incidence of many diseases in numerous geographic regions.
Mechanism of function
Vaccines are a way of artificially activating the immune system
to protect against infectious disease
. The activation occurs through priming the immune system
with an immunogen
. Stimulating immune responses with an infectious agent is known as ''immunization
''. Vaccination includes various ways of administering immunogens.
Most vaccines are administered before a patient has contracted a disease to help increase future protection. However, some vaccines are administered after the patient already has contracted a disease
. Vaccines given after exposure to smallpox are reported to offer some protection from disease or may reduce the severity of disease.
The first rabies
immunization was given by Louis Pasteur
to a child after he was bitten by a rabid
dog. Since its discovery, the rabies vaccine has been proven effective in preventing rabies in humans when administered several times over 14 days along with rabies immune globulin
and wound care. Other examples include experimental AIDS
and Alzheimer's disease
vaccines. Such immunizations aim to trigger an immune response more rapidly and with less harm than natural infection.
Most vaccines are given by injection as they are not absorbed reliably through the intestines
. Live attenuated polio, rotavirus, some typhoid, and some cholera vaccines are given orally to produce immunity in the bowel. While vaccination provides a lasting effect, it usually takes several weeks to develop. This differs from passive immunity
(the transfer of antibodies
, such as in breastfeeding), which has immediate effect.
A vaccine failure is when an organism
contracts a disease
in spite of being vaccinated against it. Primary vaccine
failure occurs when an organism's immune system
does not produce antibodies
when first vaccinated. Vaccines can fail when several series are given and fail to produce an immune response. The term "vaccine failure" does not necessarily imply that the vaccine is defective. Most vaccine failures are simply from individual variations in immune response.
Vaccination versus inoculation
The term inoculation
is often used interchangeably with vaccination. However, the terms are not synonymous. Dr Byron Plant explains: "Vaccination is the more commonly used term, which actually consists of a 'safe' injection of a sample taken from a cow suffering from cowpox... Inoculation, a practice probably as old as the disease itself, is the injection of the variola virus taken from a pustule or scab of a smallpox sufferer into the superficial layers of the skin, commonly on the upper arm of the subject. Often inoculation was done 'arm-to-arm' or, less effectively, 'scab-to-arm'..." Inoculation oftentimes caused the patient to become infected with smallpox, and in some cases the infection turned into a severe case.
Confirmed applications of inoculation for smallpox happened in China in the 1550s.
Vaccinations began in the 18th century with the work of Edward Jenner
and the smallpox vaccine.
Vaccine development and approval
Just like any medication or procedure, no vaccine can be 100% safe or effective for everyone because each person's body can react differently.
While minor side effects, such as soreness or low grade fever, are relatively common, serious side effects are very rare and occur in about 1 out of every 100,000 vaccinations and typically involve allergic reactions that can cause hives or difficulty breathing.
However, vaccines are the safest they ever have been in history and each vaccine undergoes rigorous clinical trials to ensure their safety and efficacy
Prior to human testing, vaccines are run through computer algorithms to model how they will interact with the immune system and are tested on cells in a culture.
During the next round of testing, researchers study vaccines in animals, including mice, rabbits, guinea pigs, and monkeys.
Vaccines that pass each of these stages of testing are then approved by the FDA to start a three-phase series of human testing, advancing to higher phases only if they are deemed safe and effective at the previous phase. The people in these trials participate voluntarily and are required to prove they understand the purpose of the study and the potential risks.
During phase I trials, a vaccine is tested in a group of about 20 people with the primary goal of assessing the vaccine's safety.
Phase II trials expand the testing to include 50 to several hundred people. During this stage, the vaccine's safety continues to be evaluated and researchers also gather data on the effectiveness and the ideal dose of the vaccine.
Vaccines determined to be safe and efficacious then advance to phase III trials, which focuses on the efficacy of the vaccine in hundreds to thousands of volunteers. This phase can take several years to complete and researchers use this opportunity to compare the vaccinated volunteers to those who have not been vaccinated to highlight any true reactions to the vaccine that occur.
If a vaccine passes all of the phases of testing, the manufacturer can then apply for licensure of the vaccine through the FDA. Before the FDA approves use in the general public, they extensively review the results to the clinical trials, safety tests, purity tests, and manufacturing methods and establish that the manufacturer itself is up to government standards in many other areas.
However, safety testing of the vaccines never ends.
After FDA approval, the FDA continues to monitor the manufacturing protocols, batch purity, and the manufacturing facility itself. Additionally, most vaccines also undergo phase IV trials, which monitors the safety and efficacy of vaccines in tens of thousands of people, or more, across many years.
This allows for delayed or very rare reactions to be detected and evaluated.
The Centers for Disease Control and Prevention
(CDC) has compiled a list of vaccines and their possible side effects.
The risk of side effects varies from one vaccine to the next, but below are examples of side effects and their approximate rate of occurrence with the diphtheria, tetanus, and acellular pertussis (DTaP)
vaccine, a common childhood vaccine.
Mild side effects (common)
* Mild fever (1 in 4)
* Redness, soreness, swelling at the injection site (1 in 4)
* Fatigue, poor appetite (1 in 10)
* Vomiting (1 in 50)
Moderate side effects (uncommon)
* Seizure (1 in 14,000)
* High fever (over 105 °F) (1 in 16,000)
Severe side effects (rare)
* Serious allergic reaction (1 in 1,000,000)
* Other severe problems including long-term seizure, coma, brain damage have been reported, but are so rare that it is not possible to tell if they are from the vaccine or not.
Certain vaccines have had adverse outcomes identified after being used in mass vaccination programs. In 1976 in the United States, a mass vaccination program swine flu vaccine was discontinued
after cases of Guillain–Barré syndrome
. William Foege
of the CDC estimated that the incidence of Guillain-Barré was four times higher in vaccinated people than in those not receiving the swine flu vaccine. Dengvaxia
, the only approved vaccine for Dengue fever
, was found to increase the risk of hospitalization for Dengue fever by 1.58 times in children of 9 years or younger, resulting in the suspension of a mass vaccination program in the Philippines in 2017. Pandemrix
a vaccine for the H1N1
pandemic of 2009 given to around 31 million people
was found to have a higher level of adverse events than alternative vaccines resulting in legal action. In a response to the narcolepsy reports following immunization with Pandemrix, the CDC
carried out a population-based study and found the FDA-approved 2009 H1N1 flu shots were not associated with an increased risk for the neurological disorder.
The ingredients of vaccines can vary greatly from one to the next and no two vaccines are the same. The CDC
has compiled a list of vaccines and their ingredients that is readily accessible on their website.
is an adjuvant ingredient in some vaccines. An adjuvant is a type of ingredient that is used to help the body's immune system create a stronger immune response after receiving the vaccination.
Aluminium is in a salt
form (the ionic version of an element) and is used in the following compounds: aluminium hydroxide
, aluminium phosphate
, and aluminium potassium sulfate
. For a given element, the ion form has different properties from the elemental form. Although it is possible to have aluminium toxicity, aluminium salts have been used effectively and safely since the 1930s when they were first used with the diphtheria and tetanus vaccines.
Although there is a small increase in the chance of having a local reaction to a vaccine with an aluminium salt (redness, soreness, and swelling), there is no increased risk of any serious reactions.
Certain vaccines contain a compound called thimerosal
, which is an organic compound that contains mercury
. Mercury is commonly found in two forms that differ by the number of carbon groups in its chemical structure. Methylmercury
(one carbon group) is found in fish and is the form that people usually ingest, while ethylmercury
(two carbon groups) is the form that is in thimerosal.
Although the two have similar chemical compounds, they do not have the same chemical properties and interact with the human body differently. Ethylmercury is cleared from the body faster than methylmercury and is less likely to cause toxic effects.
Thimerosal is used to prevent the growth of bacteria and fungi in vials that contain more than one dose of a vaccine.
This helps reduce the risk of potential infections and or serious illness that could occur from contamination of a vaccine vial. Although there is a small increase in risk of injection site redness and swelling with vaccines containing thimerosal, there is no increased risk of serious harm, including autism. Even though evidence supports the safety and efficacy of thimerosal in vaccines, thimerosal was removed from childhood vaccines in the United States in 2001 as a precaution.
The administration protocols, efficacy, and adverse events of vaccines are monitored by organizations of the federal government, including the CDC and FDA, and independent agencies are constantly re-evaluating vaccine practices.
As with all medications, vaccine use is determined by public health research, surveillance, and reporting to governments and the public. [
thumb|upright=1.6|Global vaccination coverage 1980 to 2019 among one year olds
The World Health Organization (WHO) estimate that vaccination averts 2–3 million deaths per year (in all age groups), and up to 1.5 million children die each year due to diseases that could have been prevented by vaccination.
They estimate that 29% of deaths of children under five years old in 2013 were vaccine preventable. In other developing parts of the world, they are faced with the challenge of having a decreased availability of resources and vaccinations. Countries such as those in Sub-Saharan Africa cannot afford to provide the full range of childhood vaccinations.
Vaccines have led to major decreases in the prevalence of infectious diseases in the United States. In 2007, studies regarding the effectiveness of vaccines on mortality or morbidity rates of those exposed to various diseases have shown almost 100% decreases in death rates, and about a 90% decrease in exposure rates. This has allowed specific organizations and states to adopt standards for recommended early childhood vaccinations. Lower income families who are unable to otherwise afford vaccinations are supported by these organizations and specific government laws. The Vaccine for Children Program and the Social Security Act are two major players in supporting lower socioeconomic groups.
In 2000, the CDC declared that measles had been eliminated in the US (defined as no disease transmission for 12 continuous months). However, with the growing anti-vaccine movement, the US has seen a resurgence of certain vaccine-preventable diseases. The measles virus has now lost its elimination status in the US as the number of measles cases continues to rise in recent years with a total of 17 outbreaks in 2018 and 465 outbreaks in 2019 (as of 4 April 2019).
Edward Jenner, a doctor in Berkeley in Gloucestershire, established the procedure of vaccination by introducing material from a cowpox vesicle on Sarah Nelmes, a milkmaid, into the arm of a boy named James Phipps. Two months later he inoculated the boy with smallpox and the disease did not develop. In 1798 Jenner published ''An Inquiry into the Causes and Effects of the Variolae Vacciniae'' which created widespread interest. He distinguished 'true' and 'spurious' cowpox (which did not give the desired effect) and developed an "arm-to-arm" method of propagating the vaccine from the vaccinated individual's pustule. Early attempts at confirmation were confounded by contamination with smallpox, but despite controversy within the medical profession and religious opposition to the use of animal material, by 1801 his report was translated into six languages and over 100,000 people were vaccinated.
The term ''vaccination'' was coined in 1800 by the surgeon Richard Dunning in his text ''Some observations on vaccination''.
In 1802 the physician Helenus Scott vaccinated dozens of children in Bombay. In the same year Scott penned a letter to the editor in the ''Bombay Courier'', declaring that "We have it now in our power to communicate the benefits of this important discovery to every part of India, perhaps to China and the whole eastern world". Subsequently vaccination became firmly established in British India. A vaccination campaign was started in the new British colony of Ceylon in 1803. By 1807 the British had vaccinated more than a million Indians and Sri Lankans against smallpox. Following a smallpox epidemic in 1816 the Kingdom of Nepal ordered smallpox vaccine and requested the English veterinarian William Moorcroft to help in launching a vaccination campaign. In the same year a law was passed in Sweden to require the vaccination of children against smallpox by the age of two. Prussia briefly introduced compulsory vaccination in 1810 and again in the 1920s, but decided against a compulsory vaccination law in 1829. A law on compulsory smallpox vaccination was introduced in the Province of Hanover in the 1820s. Following a smallpox epidemic in 1837 that caused 40,000 deaths the British government initiated a concentrated vaccination policy, starting with the Vaccination Act of 1840, which provided for universal vaccination and prohibited variolation. The Vaccination Act 1853 introduced compulsory smallpox vaccination in England and Wales. The law followed a severe outbreak of smallpox in 1851 and 1852. It provided that the poor law authorities would continue to dispense vaccination to all free of charge, but that records were to be kept on vaccinated children by the network of births registrars. It was accepted at the time, that voluntary vaccination had not reduced smallpox mortality, but the Vaccination Act 1853 was so badly implemented that it had little impact on the number of children vaccinated in England and Wales.
In the United States of America compulsory vaccination laws were upheld in the 1905 landmark case Jacobson v. Massachusetts by the Supreme Court of the United States. The Supreme Court ruled that laws could require vaccination to protect the public from dangerous communicable diseases. However, in practice the United States had the lowest rate of vaccination among industrialized nations in the early 20th century. Compulsory vaccination laws began to be enforced in the United States after World War II. In 1959 the World Health Organization (WHO) called for the eradication of smallpox worldwide, as smallpox was still endemic in 33 countries. In the 1960s six to eight children died each year in the United States from vaccination-related complications. According to the WHO there were in 1966 about 100 million cases of smallpox worldwide, causing an estimated two million death. In the 1970s there was such a small risk of contracting smallpox that the United States Public Health Service recommended for routine smallpox vaccination to be ended. By 1974 the WHO smallpox vaccination program had confined smallpox to parts of Pakistan, India, Bangladesh, Ethiopia and Somalia. In 1977 the WHO recorded the last case of smallpox infection acquired outside a laboratory in Somalia. In 1980 the WHO officially declared the world free of smallpox.
In 1974 the WHO adopted the goal of universal vaccination by 1990 to protect children against six preventable infectious diseases: measles, poliomyelitis, diphtheria, whooping cough, tetanus, and tuberculosis. In the 1980s only 20 to 40 percent of children in developing countries were vaccinated against these six diseases. In wealthy nations the number of measles cases had dropped dramatically after the introduction of the measles vaccine in 1963. WHO figures demonstrate that in many countries a decline in measles vaccination leads to a resurgence in measles cases. Measles are so contagious that public health experts believe a vaccination rate of 100 percent is needed to control the disease. Despite decades of mass vaccination polio remains a threat in India, Nigeria, Somalia, Niger, Afghanistan, Bangladesh and Indonesia. By 2006 global health experts concluded that the eradication of polio was only possible if the supply of drinking water and sanitation facilities were improved in slums. The deployment of a combined DPT vaccine against diphtheria, pertussis (whooping cough), and tetanus in the 1950s was considered a major advancement for public health. But in the course of vaccination campaigns that spanned decades, DPT vaccines became associated with high incidences of side effects. Despite improved DPT vaccines coming onto the market in the 1990s DPT vaccines became the focus of anti-vaccination campaigns in wealthy nations. As immunization rates fell outbreaks of pertussis increased in many countries.
In 2000, the Global Alliance for Vaccines and Immunization was established to strengthen routine vaccinations and introduce new and under-used vaccines in countries with a per capita GDP of under US$1000.
To eliminate the risk of outbreaks of some diseases, at various times governments and other institutions have employed policies requiring vaccination for all people. For example, an 1853 law required universal vaccination against smallpox in England and Wales, with fines levied on people who did not comply. Common contemporary U.S. vaccination policies require that children receive recommended vaccinations before entering public school.
Beginning with early vaccination in the nineteenth century, these policies were resisted by a variety of groups, collectively called antivaccinationists, who object on scientific, ethical, political, medical safety, religious, and other grounds. Common objections are that vaccinations do not work, that compulsory vaccination constitutes excessive government intervention in personal matters, or that the proposed vaccinations are not sufficiently safe.
Many modern vaccination policies allow exemptions for people who have compromised immune systems, allergies to the components used in vaccinations or strongly held objections.
In countries with limited financial resources, limited vaccination coverage results in greater morbidity and mortality due to infectious disease. More affluent countries are able to subsidize vaccinations for at-risk groups, resulting in more comprehensive and effective coverage. In Australia, for example, the Government subsidizes vaccinations for seniors and indigenous Australians.
Public Health Law Research, an independent US based organization, reported in 2009 that there is insufficient evidence to assess the effectiveness of requiring vaccinations as a condition for specified jobs as a means of reducing incidence of specific diseases among particularly vulnerable populations; that there is sufficient evidence supporting the effectiveness of requiring vaccinations as a condition for attending child care facilities and schools; and that there is strong evidence supporting the effectiveness of standing orders, which allow healthcare workers without prescription authority to administer vaccine as a public health intervention.
Allegations of vaccine injuries in recent decades have appeared in litigation in the U.S. Some families have won substantial awards from sympathetic juries, even though most public health officials have said that the claims of injuries were unfounded.
In response, several vaccine makers stopped production, which the US government believed could be a threat to public health, so laws were passed to shield manufacturers from liabilities stemming from vaccine injury claims. The safety and side effects of multiple vaccines have been tested in order to uphold the viability of vaccines as a barrier against disease. The influenza vaccine was tested in controlled trials and proven to have negligible side effects equal to that of a placebo. Some concerns from families might have arisen from social beliefs and norms that cause them to mistrust or refuse vaccinations, contributing to this discrepancy in side effects that were unfounded.
Opposition to vaccination, from a wide array of vaccine critics, has existed since the earliest vaccination campaigns.
[ It is widely accepted that the benefits of preventing serious illness and death from infectious diseases greatly outweigh the risks of rare serious adverse effects following immunization.] Some studies have claimed to show that current vaccine schedules increase infant mortality and hospitalization rates; those studies, however, are correlational in nature and therefore cannot demonstrate causal effects, and the studies have also been criticized for cherry picking the comparisons they report, for ignoring historical trends that support an opposing conclusion, and for counting vaccines in a manner that is "completely arbitrary and riddled with mistakes".
Various disputes have arisen over the morality, ethics, effectiveness, and safety of vaccination. Some vaccination critics say that vaccines are ineffective against disease or that vaccine safety studies are inadequate. Some religious groups do not allow vaccination, and some political groups oppose mandatory vaccination on the grounds of individual liberty. [ In response, concern has been raised that spreading unfounded information about the medical risks of vaccines increases rates of life-threatening infections, not only in the children whose parents refused vaccinations, but also in those who cannot be vaccinated due to age or immunodeficiency, who could contract infections from unvaccinated carriers (see herd immunity). Some parents believe vaccinations cause autism, although there is no scientific evidence to support this idea. In 2011, Andrew Wakefield, a leading proponent of the theory that MMR vaccine causes autism, was found to have been financially motivated to falsify research data and was subsequently stripped of his medical license. In the United States people who refuse vaccines for non-medical reasons have made up a large percentage of the cases of measles, and subsequent cases of permanent hearing loss and death caused by the disease.
Many parents do not vaccinate their children because they feel that diseases are no longer present due to vaccination. This is a false assumption, since diseases held in check by immunization programs can and do still return if immunization is dropped. These pathogens could possibly infect vaccinated people, due to the pathogen's ability to mutate when it is able to live in unvaccinated hosts. In 2010, California had the worst whooping cough outbreak in 50 years. A possible contributing factor was parents choosing not to vaccinate their children.] There was also a case in Texas in 2012 where 21 members of a church contracted measles because they chose not to immunize.
Vaccination and autism
The notion of a connection between vaccines and autism originated in a 1998 paper published in ''The Lancet'' whose lead author was the physician Andrew Wakefield. His study concluded that eight of the 12 patients (ages 3–10) developed behavioral symptoms consistent with autism following the MMR vaccine (an immunization against measles, mumps, and rubella).
The article was widely criticized for lack of scientific rigor and it was proven that Wakefield falsified data in the article. In 2004, 10 of the original 12 co-authors (not including Wakefield) published a retraction of the article and stated the following: "We wish to make it clear that in this paper no causal link was established between MMR vaccine and autism as the data were insufficient." In 2010, ''The Lancet'' officially retracted the article stating that several elements of the article were incorrect, including falsified data and protocols. This ''Lancet'' article has sparked a much greater anti-vaccination movement, particularly in the United States. Even though the article was fraudulent and was retracted, 1 in 4 parents still believe vaccines can cause autism.
To date, all validated and definitive studies have shown that there is no correlation between vaccines and autism. One of the studies published in 2015 confirms there is no link between autism and the MMR vaccine. Infants were given a health plan, that included an MMR vaccine, and were continuously studied until they reached 5 years old. There was no link between the vaccine and children who had a normally developed sibling or a sibling that had autism making them a higher risk for developing autism themselves.
It can be difficult to correct the memory of humans when wrong information is received prior to correct information. Even though there is much evidence to go against the Wakefield study and most of the co-authors published retractions, many continue to believe and base decisions on it as it still lingers in their memory. Studies and research are being conducted to determine effective ways to correct misinformation in the public memory. Since the Wakefield study was released over 20 years ago, it may prove easier for newer generations to be properly educated on vaccinations. A very small percentage of people have adverse reactions to vaccines, and if there is a reaction it is often mild. These reactions do not include autism.
Routes of administration
A vaccine administration may be oral, by injection (intramuscular, intradermal, subcutaneous), by puncture, transdermal or intranasal. Several recent clinical trials have aimed to deliver the vaccines via mucosal surfaces to be up-taken by the common mucosal immunity system, thus avoiding the need for injections.
Economics of vaccination
Health is often used as one of the metrics for determining the economic prosperity of a country. This is because healthier individuals are generally better suited to contributing to the economic development of a country than the sick.
There are many reasons for this. For instance, a person who is vaccinated for influenza not only protects themselves from the risk of influenza, but simultaneously also prevents themselves from infecting those around them. This leads to a healthier society, which allows individuals to be more economically productive. Children are consequently able to attend school more often and have been shown to do better academically. Similarly, adults are able to work more often, more efficiently, and more effectively.
Costs and benefits
On the whole, vaccinations induce a net benefit to society. Vaccines are often noted for their high return on investment (ROI) values, especially when considering the long-term effects. Some vaccines have much higher ROI values than others. Studies have shown that the ratios of vaccination benefits to costs can differ substantially—from 27:1 for diphtheria/pertussis, to 13.5:1 for measles, 4.76:1 for varicella, and 0.68–1.1 : 1 for pneumococcal conjugate.
Some governments choose to subsidize the costs of vaccines, due to some of the high ROI values attributed to vaccinations. The United States subsidizes over half of all vaccines for children, which costs between $400 and $600 each. Although most children do get vaccinated, the adult population of the USA is still below the recommended immunization levels. Many factors can be attributed to this issue. Many adults who have other health conditions are unable to be safely immunized, whereas others opt not to be immunized for the sake of private financial benefits. Many Americans are underinsured, and, as such, are required to pay for vaccines out-of-pocket. Others are responsible for paying high deductibles and co-pays. Although vaccinations usually induce long-term economic benefits, many governments struggle to pay the high short-term costs associated with labor and production. Consequently, many countries neglect to provide such services.
The Coalition for Epidemic Preparedness Innovations published a study in ''The Lancet'' in 2018 which estimated the costs of developing vaccines for diseases that could escalate into global humanitarian crises. They focused on 11 diseases which cause relatively few deaths at present and primarily strike the poor which have been highlighted as pandemic risks:
*Crimean Congo hemorrhagic fever
*Marburg virus disease
*Middle East respiratory syndrome coronavirus
*Nipah virus infection
*Rift Valley fever
*Severe acute respiratory syndrome
*Severe fever with thrombocytopenia syndrome
They estimated that it would cost between $2.8 billion and $3.7 billion to develop at least one vaccine for each of them. This should be set against the potential cost of an outbreak. The 2003 SARS outbreak in East Asia cost $54 billion.
File:Jenner phipps 01.jpg|Dr Jenner performing his first vaccination on James Phipps, a boy of age 8. 14 May 1796. Painting by Ernest Board (early 20th century)
File:The cow pock.jpg|James Gillray's ''The Cow-Pock—or—the Wonderful Effects of the New Inoculation!'', an 1802 caricature of vaccinated patients who feared it would make them sprout cowlike appendages
File:Londre wellcome institute boilly vaccinee.jpg|''La vaccine'' or ''Le préjugé vaincu'' by Louis-Léopold Boilly, 1807
File:A doctor vaccinating a small girl, other girls with loosened Wellcome V0016682.jpg|''A doctor vaccinating a small girl, other girls with loosened blouses wait their turn apprehensively'' by Lance Calkin
File:'Serum straight from the horse'., inoculation caricature Wellcome L0009827.jpg|German caricature showing von Behring extracting the serum with a tap.
File:The history of vaccination seen from an economic point of vi Wellcome V0011691.jpg|''Les Malheurs de la Vaccine'' (The history of vaccination seen from an economic point of view: A pharmacy up for sale; an outmoded inoculist selling his premises; Jenner, to the left, pursues a skeleton with a lancet)
*H5N1 clinical trials
*Immunization during pregnancy
*List of vaccine topics
*Misinformation related to vaccination
*Vaccination and religion
*Vaccination of dogs
*World Immunization Week
*Coronavirus disease 2019
U.S. government Vaccine Research Center
Information regarding preventive vaccine research studies
The Vaccine Page
links to resources in many countries.
Immunisation schedule for the UK. Published by the UK Department of Health.
- 'National Immunization Program: leading the way to healthy lives', US Centers for Disease Control (CDC information on vaccinations)
- 'Mercury and Vaccines (Thimerosal)', US Centers for Disease Control
- Vaccines timeline
- Immunization Action Coalition' (nonprofit working to increase immunization rates)
- 'Immunizations, vaccines and biologicals: Towards a World free of Vaccine Preventable Diseases', World Health Organization (WHO's global vaccination campaign website)
Vaccinations in the EU
History of Vaccines
Medical education site from the College of Physicians of Philadelphia, the oldest medical professional society in the US
Images of vaccine-preventable diseases
BBC Radio 4 discussion with Nadja Durbach, Chris Dye & Sanjoy Bhattacharya (''In Our Time'', 20 Apr. 2006)