Vaccine controversy

# Overview
A vaccine controversy is a dispute over the morality, ethics, effectiveness, or safety of vaccination. Medical opinion is that the benefits of preventing suffering and death from infectious diseases greatly outweigh the risks of adverse effects following immunization. Some vaccination critics say that vaccines are ineffective against disease, that vaccine safety studies are inadequate, or raise other objections. Some religious groups oppose vaccination as a matter of doctrine, and some political groups oppose mandatory vaccination on the grounds of individual liberty.

# Benefits of vaccination
A number of arguments regarding the benefits of mass vaccination have been advanced:

## Life-saving
Mass vaccination campaigns were essential components of strategies that led to the eradication of smallpox, which once killed as many as every seventh child in Europe, and the near-eradication of polio. As a more modest example, incidence of invasive disease with Haemophilus influenzae, a major cause of bacterial meningitis and other serious disease in children, has decreased by over 99% in the U.S. since the introduction of a vaccine in 1988. Fully vaccinating all U.S. children born in a given year from birth to adolescence saves an estimated 33,000 lives and prevents an estimated 14 million infections.

## Cost
Vaccines are a cost-effective and preventive way of promoting health, compared to the treatment of acute or chronic disease. In the U.S. during the year 2001, routine childhood immunizations against seven diseases were estimated to save over $40 billion per birth-year cohort in overall social costs including $10 billion in direct health costs, and the societal benefit-cost ratio for these vaccinations was estimated to be 16.5.

## Population health
Incomplete vaccine coverage increases the risk of disease for the entire population, including those who have been vaccinated. One study found that doubling the number of unvaccinated individuals would increase the risk of measles in vaccinated children anywhere from 530%. A second study provided evidence that the risk of measles and pertussis increased in vaccinated children proportionally to the number of unvaccinated individuals among them, again highlighting the evident efficacy of widespread vaccine coverage for public health.

## Events following reductions in vaccination
In several countries, reductions in the use of some vaccines were followed by increases in the diseases' morbidity and mortality. According to the Centers for Disease Control and Prevention, continued high levels vaccine coverage are necessary to prevent resurgence of diseases which have been nearly eliminated.
An anti-vaccination campaign motivated by religious objections, by concerns about effectiveness, and by concerns about individual rights, led to the vaccination rate in Stockholm dropping to just over 40%, compared to about 90% elsewhere in Sweden. A major smallpox epidemic then started in 1873. It led to a rise in vaccine uptake and an end of the epidemic.
A 1974 report ascribed 36 reactions to whooping cough (pertussis) vaccine, a prominent public-health academic claimed that the vaccine was only marginally effective and questioned whether its benefits outweigh its risks, and extended television and press coverage caused a scare. Vaccine uptake in the UK decreased from 81% to 31% and pertussis epidemics followed, leading to deaths of some children. Mainstream medical opinion continued to support the effectiveness and safety of the vaccine; public confidence was restored after the publication of a national reassessment of vaccine efficacy. Vaccine uptake then increased to levels above 90% and disease incidence declined dramatically.
In the vaccination moratorium period that occurred when Sweden suspended vaccination against whooping cough (pertussis) from 1979 to 1996, 60% of the country's children contracted the potentially fatal disease before the age of ten years; close medical monitoring kept the death rate from whooping cough at about one per year. Pertussis continues to be a major health problem in developing countries, where mass vaccination is not practiced; the World Health Organization estimates it caused 294,000 deaths in 2002.
An outbreak at a religious community and school in The Netherlands illustrates the effect of measles in an unvaccinated population. The population in the several provinces affected had a high level of immunization with the exception of one of the religious denominations who traditionally do not accept vaccination. The three measles-related deaths and 68 hospitalizations that occurred among 2961 cases in the Netherlands demonstrate that measles can be severe and may result in death even in industrialized countries.
From late 1999 until the summer of 2000, there was a measles outbreak in North Dublin, Ireland. At the time, the national immunization level had fallen below 80%, and in part of North Dublin the level was around 60%. There were more than 100 hospital admissions from over 300 cases. Three children died and several more were gravely ill, some requiring mechanical ventilation to recover.
In the early 2000s, conservative religious leaders in northern Nigeria, suspicious of Western medicine, advised their followers to not have their children vaccinated with oral polio vaccine. The boycott was endorsed by the governor of Kano State, and immunization was suspended for several months. Subsequently, polio reappeared in a dozen formerly polio-free neighbors of Nigeria, and genetic tests showed the virus was the same one that originated in northern Nigeria: Nigeria had become a net exporter of polio virus to its African neighbors. People in the northern states were also reported to be wary of other vaccinations, and Nigeria reported over 20,000 measles cases and nearly 600 deaths from measles from January through March 2005. In 2006 Nigeria accounted for over half of all new polio cases worldwide. Outbreaks continued thereafter; for example, at least 200 children died in a late-2007 measles outbreak in Borno State.
A 2005 measles outbreak in Indiana was due to children whose parents had refused to have them vaccinated. Most cases of pediatric tetanus in the U.S. occur in children whose parents objected to their vaccination.

# Arguments against
Since the inception of vaccination in the late 18th century, opponents have argued that vaccines do not work, that they are dangerous, that individuals should rely on personal hygiene instead, or that mandatory vaccinations violate individual rights or religious principles.

## Effectiveness
Some vaccine critics claim that there have never been any benefits to public health from vaccination. They argue that all the reduction of communicable diseases which were rampant in conditions where overcrowding, poor sanitation, almost non-existent hygiene and a yearly period of very restricted diet existed, are reduced because of changes in conditions excepting vaccination. Other critics argue that immunity given by vaccines is only temporary and requires boosters, whereas those who survive the disease become permanently immune. As discussed below, the philosophies of some alternative medicine practitioners are incompatible with the idea that vaccines are effective.
Children who survive diseases like diphtheria develop a natural immunity that lasts longer than immunity developed via vaccination. Even though the overall mortality rate is much lower with vaccination, the percentage of adults protected against the disease may also be lower. Vaccination critics argue that for diseases like diphtheria the extra risk to older or weaker adults may outweigh the benefit of lowering the mortality rate among the general population.

## Safety
Few deny the vast improvements vaccination has made to public health; a more common concern is their safety. All vaccines may cause side effects, and immunization safety is a real concern. Controversies in this area revolve around the question of whether the risks of adverse events following immunization outweigh the benefits of preventing adverse effects of common diseases. Critics point out that lack of evidence of harm is not the same as evidence of safety.

### Auto-immune disorders
If individual or multiple vaccinations were to "weaken the immune system", as some vaccine critics contend, then one would expect an increase in hospitalizations for other infections following immunization. A large epidemiological study, involving all 805,206 children born in Denmark between 1990 and 2001, found no evidence that multiple-antigen vaccines, nor the increasing number of vaccinations given to children, led to a higher rate of infections.
A 2006 study of health data from the Canadian province of Ontario (where influenza vaccines have been free since 2000), found a correlation between receiving a vaccination and developing Guillain-Barre syndrome (GBS) in individuals, but no increase of GBS in the general population corresponding to vaccination popularity. The authors concluded, "individuals who receive the influenza vaccine should be advised of the potential risk for GBS".

### Aluminum
Aluminum compounds are used in many vaccines as immunologic adjuvants, to stimulate the immune system and increase the response of the vaccine. Although these vaccines can elicit redness, itching, and low-grade fever, and aluminum as such is considered neurotoxic for humans, its use in vaccines has not been associated with serious adverse events. In some cases aluminum-containing vaccines are associated with macrophagic myofasciitis (MMF), localized microscopic lesions containing aluminum salts that persist up to 8 years. However, recent case-controlled studies have found no specific clinical symptoms in individuals with biopsies showing MMF, and there is no evidence that aluminum-containing vaccines are a serious health risk or justify changes to immunization practice.

### Thiomersal
The organic mercury content of thiomersal in child vaccines has been alleged to contribute to autism, and thousands of parents in the United States have pursued legal compensation from a federal fund.
In July 1999, the Centers for Disease Control (CDC) and the American Academy of Pediatrics (AAP) asked vaccine makers to remove thiomersal from vaccines as quickly as possible, and thiomersal has been phased out of most U.S. and European vaccines. However, the 2004 Institute of Medicine (IOM) panel favoured rejecting any causal relationship between thiomersal-containing vaccines and autism. The CDC and the AAP followed the precautionary principle, which assumes that there is no harm in exercising caution even if it later turns out to be unwarranted, but their 1999 action sparked confusion and controversy that has diverted attention and resources away from efforts to determine the causes of autism. The current scientific consensus is that there is no convincing scientific evidence that thiomersal causes or helps cause autism.

### MMR vaccine
In the UK, the MMR vaccine was the subject of controversy after publication of a 1998 paper by Andrew Wakefield, et al., reporting a study of 12 children mostly with autism spectrum disorders with onset soon after administration of the vaccine. During a 1998 press conference, Wakefield suggested that giving children the vaccines in three separate doses would be safer than a single vaccination. This suggestion was not supported by the paper, and several subsequent peer-reviewed studies have failed to show any association between the vaccine and autism. Wakefield has been heavily criticized on scientific grounds and for triggering a decline in vaccination rates, as well as on ethical grounds for the way the research was conducted.
In 2004 the MMR-and-autism interpretation of the paper was formally retracted by 10 of Wakefield's 12 co-authors. The CDC, the IOM of the National Academy of Sciences, and the UK National Health Service have all concluded that there is no evidence of a link between the MMR vaccine and autism. A systematic review by the Cochrane Library concluded that there is no credible link between the MMR vaccine and autism, that MMR has prevented diseases that still carry a heavy burden of death and complications, that the lack of confidence in MMR has damaged public health, and that design and reporting of safety outcomes in MMR vaccine studies are largely inadequate.

### Prenatal infection
There is evidence that schizophrenia is associated with prenatal exposure to rubella, influenza, and toxoplasmosis infection. For example, one study found a seven-fold increased risk of schizophrenia when mothers were exposed to influenza in the first trimester of gestation. This may have public health implications, as strategies for preventing infection include vaccination, antibiotics, and simple hygiene. When weighing the benefits of protecting the woman and fetus from influenza against the potential risk of vaccine-induced antibodies that could conceivably contribute to schizophrenia, influenza vaccination for women of reproductive age still makes sense, but it is not known whether vaccination during pregnancy helps or harms. The CDC's Advisory Committee on Immunization Practices, the American College of Obstetricians and Gynecologists, and the American Academy of Family Physicians all recommend routine flu shots for pregnant women, for several reasons:
- their risk for serious influenza-related medical complications during the last two trimesters;
- their greater rates for flu-related hospitalizations compared to nonpregnant women;
- the possible transfer of maternal anti-influenza antibodies to children, protecting the children from the flu; and
- several studies that found no harm to pregnant women or their children from the vaccinations.
Despite this recommendation, only 16% of healthy pregnant U.S. women surveyed in 2005 had been vaccinated against the flu.

## Vaccine makers' motivations and actions
Critics allege that the profit motive explains why vaccination is required, and that vaccine makers cover up or suppress information, or generate misinformation, about safety or effectiveness.

## Individual liberty
Compulsory vaccination policies have provoked opposition at various times from people who say that governments should not infringe on the freedom of an individual to choose medications, even if the choice increases the risk of disease to others. If a vaccination program successfully reduces the disease threat, it may reduce the perceived risk of disease enough so that an individual's optimal strategy is to refuse vaccination at coverage levels below those optimal for the community. If many exemptions are granted to mandatory vaccination rules, the resulting free rider problem may cause loss of herd immunity, substantially increasing risks even to vaccinated individuals.

## Religion
Vaccination has been opposed on religious grounds ever since it was introduced, even when vaccination is not compulsory. Early Christian opponents argued that if God had decreed that someone should die of smallpox, it would be a sin to thwart God's will via vaccination. Opposition continues to the present day, on various grounds. For example, the Family Research Council, a conservative U.S. Christian group, opposes mandatory vaccination for diseases typically spread via sexual contact, arguing that the possibility of disease deters sexual promiscuity.
Many governments allow parents to opt out of their children's otherwise-mandatory vaccinations for religious reasons; some parents falsely claim religious beliefs to get vaccination exemptions.

## Alternative medicine
Many forms of alternative medicine are based on philosophies that oppose vaccination and have practitioners who voice their opposition. These include anthroposophy, some elements of the chiropractic community, non-medically trained homoeopaths, and naturopaths.
Historically, chiropractic strongly opposed vaccination based on its belief that all diseases were traceable to causes in the spine, and therefore could not be affected by vaccines; Daniel D. Palmer, the founder of chiropractic, wrote, "It is the very height of absurdity to strive to 'protect' any person from smallpox or any other malady by inoculating them with a filthy animal poison." Vaccination remains controversial within chiropractic. The American Chiropractic Association and the International Chiropractic Association support individual exemptions to compulsory vaccination laws, and a 1995 survey of U.S. chiropractors found that about a third believed there was no scientific proof that immunization prevents disease. The Canadian Chiropractic Association supports vaccination; however, surveys in Canada in 2000 and 2002 found that only 40% of chiropractors supported vaccination, and that over a quarter opposed it and advised patients against vaccinating themselves or their children. Although most chiropractic writings on vaccination focus on its negative aspects, antivaccination sentiment is espoused by what appears to be a minority of chiropractors.
Several surveys have shown that some practitioners of homeopathy, particularly lay homeopaths, advise patients against vaccination. For example, a survey of registered homeopaths in Austria found that only 28% considered immunization to be an important preventive measure, and 83% of homeopaths surveyed in Sydney, Australia did not recommend vaccination. Many practitioners of naturopathy also oppose vaccination.

# Dispute resolution
The U.S. Vaccine Injury Compensation Program (VICP) was created to provide a federal no-fault system for compensating vaccine-related injuries or death. It was established after a scare in the 1980s over the DPT vaccine: even though claims of side effects were later generally discredited, large jury awards had been given to some claimants of DPT vaccine injuries, and most DPT vaccine makers had ceased production. Claims against vaccine manufacturers must be heard first in the vaccine court. By 2008 the fund had paid out 2,114 awards totaling $1.7 billion. Thousands of autism-related claims are pending before the court, and have not yet been resolved.

# History of anti-vaccinationism
Religious arguments against inoculation were advanced even before the work of Edward Jenner; for example, in a 1772 sermon entitled "The Dangerous and Sinful Practice of Inoculation" the English theologian Rev. Edward Massey argued that diseases are sent by God to punish sin and that any attempt to prevent smallpox via inoculation is a "diabolical operation". Some anti-vaccinationists still base their stance against vaccination with reference to their religious beliefs.
After Jenner's work, vaccination became widespread in the United Kingdom in the early 1800s. Variolation, which had preceded vaccination, was banned in 1840 because of its greater risks. Public policy and successive Vaccination Acts first encouraged vaccination and then made it mandatory for all infants in 1853, with the highest penalty for refusal being a prison sentence. This was a significant change in the relationship between the British state and its citizens, and there was a public backlash. After an 1867 law extended the requirement to age 14 years, its opponents focused concern on infrigement of individual freedom, and eventually a 1898 law allowed for conscientious objection to compulsory vaccination.
In the 19th century, the city of Leicester in the UK achieved a high level of isolation of smallpox cases and great reduction in spread compared to other areas. The mainstay of Leicester's approach to conquering smallpox was to decline vaccination and put their public funds into sanitary improvements. Bigg's account of the public health procedures in Leicester, presented as evidence to the Royal Commission, refers to erysipelas, an infection of the superficial tissues which was a complication of any surgical procedure.
In the U.S., President Thomas Jefferson took a close interest in vaccination, alongside Dr. Waterhouse, chief physician at Boston. Jefferson encouraged the development of ways to transport vaccine material through the Southern states, which included measures to avoid damage by heat, a leading cause of ineffective batches. Smallpox outbreaks were contained by the latter half of the 19th century, a development widely attributed to vaccination of a large portion of the population.
Vaccination rates fell after this decline in smallpox cases, and the disease again became epidemic in the 1870s (see smallpox).
Anti-vaccination activity increased again in the U.S. in the late 19th century. After a visit to New York in 1879 by William Tebb, a prominent British anti-vaccinationist, the Anti-Vaccination Society of America was founded. The New England Anti-Compulsory Vaccination League was formed in 1882, and the Anti-Vaccination League of New York City in 1885.
In the early 19th century, the anti-vaccination movement drew members from across a wide range of society; more recently, it has been reduced to a predominantly middle-class phenomenon. Arguments against vaccines in the 21st century are often similar to those of 19th-century anti-vaccinationists.