MMR vaccine
Encyclopedia
The MMR vaccine is an immunization
shot against measles
, mumps
, and rubella
(also called German measles). It was first developed by Maurice Hilleman
while at Merck
in the late 1960s.
The vaccine is a mixture of three live attenuated virus
es, administered via injection. The shot is generally administered to children around the age of one year, with a second dose before starting school (i.e. age 4/5). The second dose is not a booster
; it is a dose to produce immunity in the small number of persons (2–5%) who fail to develop measles immunity after the first dose. In the United States, the vaccine was licensed in 1971 and the second dose was introduced in 1989.
It is widely used around the world; since introduction of its earliest versions in the 1970s, over 500 million doses have been used in over 60 countries. As with all vaccination
s, long-term effects and efficacy
are subject to continuing study. The vaccine is sold by Merck
as M-M-R II, GlaxoSmithKline Biologicals as Priorix, Serum Institute of India
as Tresivac, and Sanofi Pasteur
as Trimovax.
It is usually considered a childhood vaccination. However, it is also recommended for use in some cases of adults with HIV
.
, its incidence was so high that infection with measles was felt to be "as inevitable as death and taxes." Today, the incidence
of measles has fallen to less than 1% of people under the age of 30 in countries with routine childhood vaccination. Reported cases of measles in the United States fell from hundreds of thousands to tens of thousands per year following introduction of the vaccine in 1963. Increasing uptake of the vaccine following outbreaks in 1971 and 1977 brought this down to thousands of cases per year in the 1980s. An outbreak of almost 30,000 cases in 1990 led to a renewed push for vaccination and the addition of a second vaccine to the recommended schedule. Fewer than 200 cases have been reported each year since 1997, and the disease is no longer considered endemic.
The benefit of measles vaccination in preventing illness, disability, and death has been well documented. The first 20 years of licensed measles vaccination in the U.S. prevented an estimated 52 million cases of the disease, 17,400 cases of mental retardation
, and 5,200 deaths. During 1999–2004, a strategy led by the World Health Organization
and UNICEF led to improvements in measles vaccination coverage that averted an estimated 1.4 million measles deaths worldwide.
Measles is endemic
worldwide. Although it was declared eliminated from the U.S. in 2000, high rates of vaccination and good communication with persons who refuse vaccination is needed to prevent outbreaks and sustain the elimination of measles in the U.S. Of the 66 cases of measles reported in the U.S. in 2005, slightly over half were attributable to one unvaccinated individual who acquired measles during a visit to Romania
. This individual returned to a community with many unvaccinated children. The resulting outbreak infected 34 people, mostly children and virtually all unvaccinated; 9% were hospitalized, and the cost of containing the outbreak was estimated at $167,685. A major epidemic was averted due to high rates of vaccination in the surrounding communities.
Mumps
is another viral
disease
of childhood that was once very common. If mumps is acquired by a male who is past puberty
, a possible complication is bilateral orchitis
which can in some cases lead to sterility
.
Rubella
, otherwise known as German measles, was also very common before the advent of widespread vaccination. The major risk of rubella is in pregnancy. If a pregnant
woman is infected, her baby may contract congenital rubella
from her, which can cause significant congenital defects.
All three diseases are highly contagious.
The combined MMR vaccine was introduced to induce immunity less painfully than three separate injections at the same time, and sooner and more efficiently than three injections given on different dates.
In 2005, the Cochrane Library
published a review of 31 scientific studies. One of its main results: "We could not identify studies assessing the effectiveness of MMR that fulfilled our inclusion criteria even though the impact of mass immunisation on the elimination of the diseases has been largely demonstrated." Its authors concluded, "Existing evidence on the safety and effectiveness of MMR vaccine supports current policies of mass immunisation aimed at global measles eradication in order to reduce morbidity and mortality associated with mumps and rubella."
For example, in the case of mumps and measles viruses, the virus strains were grown in embryonated hens' eggs and chick embryo cell cultures. This produced strains of virus which were adapted for the hens egg and less well-suited for human cells. These strains are therefore called attenuated strains. They are sometimes referred to as neuroattenuated because these strains are less virulent
to human neurons than the wild strains.
The Rubella component, Meruvax, is propagated using a human cell line (WI-38, named for the Wistar Institute
) derived in 1961 from embryonic lung tissue. This cell line was originally prepared from tissues of aborted fetuses, raising religious objections
.
MMR II is supplied freeze-dried (lyophilized) and contains live viruses. Before injection it is reconstituted with the solvent provided.
The MMR vaccine is administered by a subcutaneous injection
.The second dose may be given as early as one month after the first dose. The second dose is not a booster
; it is a dose to produce immunity in the small number of persons (2–5%) who fail to develop measles immunity after the first dose. In the U.S. it is done before entry to kindergarten
because that is a convenient time.
, rarely serious, may occur from each component of the MMR vaccine. 10% of children develop fever, malaise
and a rash 5–21 days after the first vaccination; 5% develop temporary joint pain
. Older women appear to be more at risk of joint pain, acute arthritis
, and even (rarely) chronic arthritis. Anaphylaxis
is an extremely rare but serious allergic reaction to the vaccine. One cause can be egg allergy
. The vaccine product brief lists many other possible adverse reactions.
The number of reports on neurologic disorders is very small, other than evidence for an association between a form of the MMR vaccine containing the Urabe mumps strain and rare adverse events of aseptic meningitis
, a transient mild form of viral meningitis. The UK National Health Service
stopped using the Urabe mumps strain in the early 1990s due to cases of transient mild viral meningitis, and switched to a form using the Jeryl Lynn
mumps strain instead. The Urabe strain remains in use in a number of countries; MMR with the Urabe strain is much cheaper to manufacture than with the Jeryl Lynn
strain, and a strain with higher efficacy
along with a somewhat higher rate of mild side effects may still have the advantage of reduced incidence of overall adverse events.
The Cochrane Library review found that, compared to placebo, MMR vaccine was associated with fewer upper respiratory tract infections, more irritability, and a similar number of other adverse effects. The review also found several problems in the quality of MMR vaccine safety studies, and recommended the adoption of standardized definitions of adverse events. The review's abstract concludes, "The design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate. The evidence of adverse events following immunisation with MMR cannot be separated from its role in preventing the target diseases."
, the MMR vaccine was the subject of controversy after publication of a 1998 paper by Andrew Wakefield
et al. reporting a study of twelve children who had bowel symptoms along with autism
or other disorders, including cases where onset was believed by the parents to be soon after administration of MMR vaccine. In 2010, Wakefield's research was found by the General Medical Council
to have been "dishonest", and The Lancet
fully retracted the original paper. The research was declared fraudulent in 2011 by the British Medical Journal
. Several subsequent peer-reviewed studies have failed to show any association between the vaccine and autism.
The Centers for Disease Control and Prevention
, the Institute of Medicine
of the National Academy of Sciences
, the UK National Health Service
and the Cochrane Library review have all concluded that there is no evidence of a link between the MMR vaccine and autism.
Administering the vaccines in three separate doses does not reduce the chance of adverse effects, and it increases the opportunity for infection by the two diseases not immunized against first. Health experts have criticized media reporting of the MMR-autism controversy for triggering a decline in vaccination rates. Before publication of Wakefield's findings, the inoculation rate for MMR in the UK was 92%; after publication, the rate dropped to below 80%. In 1998, there were 56 measles cases in the UK; by 2008, there were 1348 cases, with 2 confirmed deaths.
In Japan, the MMR vaccination has been discontinued, with single vaccines being used for each disease. Rates of autism diagnosis have continued to increase, showing no correlation with the change.
of 9 per 10,000 vaccinations with MMRV, as opposed to 4 per 10,000 for separate MMR and varicella injections; U.S. health officials therefore do not express a preference for use of MMRV vaccine over separate injections.
Immunization
Immunization, or immunisation, is the process by which an individual's immune system becomes fortified against an agent ....
shot against measles
Measles
Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...
, mumps
Mumps
Mumps is a viral disease of the human species, caused by the mumps virus. Before the development of vaccination and the introduction of a vaccine, it was a common childhood disease worldwide...
, and rubella
Rubella
Rubella, commonly known as German measles, is a disease caused by the rubella virus. The name "rubella" is derived from the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is...
(also called German measles). It was first developed by Maurice Hilleman
Maurice Hilleman
Maurice Ralph Hilleman was an American microbiologist who specialized in vaccinology and developed over three dozen vaccines, more than any other scientist...
while at Merck
Merck & Co.
Merck & Co., Inc. , also known as Merck Sharp & Dohme or MSD outside the United States and Canada, is one of the largest pharmaceutical companies in the world. The Merck headquarters is located in Whitehouse Station, New Jersey, an unincorporated area in Readington Township...
in the late 1960s.
The vaccine is a mixture of three live attenuated virus
Attenuated virus
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 virus .-Examples:Examples of...
es, administered via injection. The shot is generally administered to children around the age of one year, with a second dose before starting school (i.e. age 4/5). The second dose is not a booster
Booster dose
In medicine, a booster dose is an extra administration of a vaccine after an earlier dose. After initial immunization, a booster injection or booster dose is a re-exposure to the immunizing antigen. It is intended to increase immunity against that antigen back to protective levels after it has been...
; it is a dose to produce immunity in the small number of persons (2–5%) who fail to develop measles immunity after the first dose. In the United States, the vaccine was licensed in 1971 and the second dose was introduced in 1989.
It is widely used around the world; since introduction of its earliest versions in the 1970s, over 500 million doses have been used in over 60 countries. As with all vaccination
Vaccination
Vaccination is the administration of antigenic material to stimulate the immune system of an individual to develop adaptive immunity to a disease. Vaccines can prevent or ameliorate the effects of infection by many pathogens...
s, long-term effects and efficacy
Efficacy
Efficacy is the capacity to produce an effect. It has different specific meanings in different fields. In medicine, it is the ability of an intervention or drug to reproduce a desired effect in expert hands and under ideal circumstances.- Healthcare :...
are subject to continuing study. The vaccine is sold by Merck
Merck & Co.
Merck & Co., Inc. , also known as Merck Sharp & Dohme or MSD outside the United States and Canada, is one of the largest pharmaceutical companies in the world. The Merck headquarters is located in Whitehouse Station, New Jersey, an unincorporated area in Readington Township...
as M-M-R II, GlaxoSmithKline Biologicals as Priorix, Serum Institute of India
Serum Institute of India
Serum Institute of India is a manufacturer of Immunobiological including vaccines in India. The company is managed by the Poonawalla group- fully owned by Cyrus Poonawalla. The company is the fifth biggest vaccinemaker by volume, the top four being GlaxoSmithKline, Sanofi-Aventis, Merck and Novartis...
as Tresivac, and Sanofi Pasteur
Sanofi pasteur
Sanofi Pasteur is the vaccines division of sanofi-aventis Group. It is the largest company in the world devoted entirely to vaccines.- History :...
as Trimovax.
It is usually considered a childhood vaccination. However, it is also recommended for use in some cases of adults with HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
.
Effectiveness
Before the widespread use of a vaccine against measlesMeasles
Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...
, its incidence was so high that infection with measles was felt to be "as inevitable as death and taxes." Today, the incidence
Incidence (epidemiology)
Incidence is a measure of the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator.Incidence proportion is the...
of measles has fallen to less than 1% of people under the age of 30 in countries with routine childhood vaccination. Reported cases of measles in the United States fell from hundreds of thousands to tens of thousands per year following introduction of the vaccine in 1963. Increasing uptake of the vaccine following outbreaks in 1971 and 1977 brought this down to thousands of cases per year in the 1980s. An outbreak of almost 30,000 cases in 1990 led to a renewed push for vaccination and the addition of a second vaccine to the recommended schedule. Fewer than 200 cases have been reported each year since 1997, and the disease is no longer considered endemic.
The benefit of measles vaccination in preventing illness, disability, and death has been well documented. The first 20 years of licensed measles vaccination in the U.S. prevented an estimated 52 million cases of the disease, 17,400 cases of mental retardation
Mental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
, and 5,200 deaths. During 1999–2004, a strategy led by the World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
and UNICEF led to improvements in measles vaccination coverage that averted an estimated 1.4 million measles deaths worldwide.
Measles is endemic
Endemic (epidemiology)
In epidemiology, an infection is said to be endemic in a population when that infection is maintained in the population without the need for external inputs. For example, chickenpox is endemic in the UK, but malaria is not...
worldwide. Although it was declared eliminated from the U.S. in 2000, high rates of vaccination and good communication with persons who refuse vaccination is needed to prevent outbreaks and sustain the elimination of measles in the U.S. Of the 66 cases of measles reported in the U.S. in 2005, slightly over half were attributable to one unvaccinated individual who acquired measles during a visit to Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
. This individual returned to a community with many unvaccinated children. The resulting outbreak infected 34 people, mostly children and virtually all unvaccinated; 9% were hospitalized, and the cost of containing the outbreak was estimated at $167,685. A major epidemic was averted due to high rates of vaccination in the surrounding communities.
Mumps
Mumps
Mumps is a viral disease of the human species, caused by the mumps virus. Before the development of vaccination and the introduction of a vaccine, it was a common childhood disease worldwide...
is another viral
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
of childhood that was once very common. If mumps is acquired by a male who is past puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
, a possible complication is bilateral orchitis
Orchitis
Orchitis or orchiditis is a condition of the testes involving inflammation. It can also involve swelling and frequent infection.-Symptoms:Symptoms of orchitis are similar to those of testicular torsion...
which can in some cases lead to sterility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
.
Rubella
Rubella, commonly known as German measles, is a disease caused by the rubella virus. The name "rubella" is derived from the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is...
, otherwise known as German measles, was also very common before the advent of widespread vaccination. The major risk of rubella is in pregnancy. If a pregnant
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
woman is infected, her baby may contract congenital rubella
Congenital rubella syndrome
Congenital rubella syndrome can occur in a developing fetus of a pregnant woman who has contracted rubella during her first trimester. If infection occurs 0–28 days before conception, there is a 43% chance the infant will be affected. If the infection occurs 0–12 weeks after conception, there is a...
from her, which can cause significant congenital defects.
All three diseases are highly contagious.
The combined MMR vaccine was introduced to induce immunity less painfully than three separate injections at the same time, and sooner and more efficiently than three injections given on different dates.
In 2005, the Cochrane Library
Cochrane Library
The Cochrane Library is a collection of databases in medicine and other healthcare specialties provided by the Cochrane Collaboration and other organisations. At its core is the collection of Cochrane Reviews, a database of systematic reviews and meta-analyses which summarize and interpret the...
published a review of 31 scientific studies. One of its main results: "We could not identify studies assessing the effectiveness of MMR that fulfilled our inclusion criteria even though the impact of mass immunisation on the elimination of the diseases has been largely demonstrated." Its authors concluded, "Existing evidence on the safety and effectiveness of MMR vaccine supports current policies of mass immunisation aimed at global measles eradication in order to reduce morbidity and mortality associated with mumps and rubella."
Development, formulation and administration
The component viral strains of MMR vaccine were developed by propagation in animal and human cells. The live viruses require animal or human cells as a host for production of more virus.For example, in the case of mumps and measles viruses, the virus strains were grown in embryonated hens' eggs and chick embryo cell cultures. This produced strains of virus which were adapted for the hens egg and less well-suited for human cells. These strains are therefore called attenuated strains. They are sometimes referred to as neuroattenuated because these strains are less virulent
Virulence
Virulence is by MeSH definition the degree of pathogenicity within a group or species of parasites as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism - its ability to cause disease - is determined by its...
to human neurons than the wild strains.
The Rubella component, Meruvax, is propagated using a human cell line (WI-38, named for the Wistar Institute
Wistar Institute
The Wistar Institute is a biomedical center, with a focus on cancer research and vaccine development. It is located in the University City section of Philadelphia, Pa...
) derived in 1961 from embryonic lung tissue. This cell line was originally prepared from tissues of aborted fetuses, raising religious objections
Vaccination and religion
Vaccination and religion have interrelations of varying kinds.-Historical:Catholic and Anglican missionaries vaccinated Northwest Coast Indians during an 1862 smallpox epidemic....
.
| Disease Immunized | Component Vaccine | Virus Strain | Propagation Medium | Growth Medium Growth medium A growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells, or small plants like the moss Physcomitrella patens.There are different types of media for growing different types of cells.... |
|---|---|---|---|---|
| Measles Measles Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses... |
Attenuvax | Enders' attenuated Edmonston strain | chick embryo cell culture | Medium 199 |
| Mumps Mumps Mumps is a viral disease of the human species, caused by the mumps virus. Before the development of vaccination and the introduction of a vaccine, it was a common childhood disease worldwide... |
Mumpsvax Mumpsvax Mumpsvax is a mumps vaccine made of mumps virus. Mumpsvax is a product of Merck & Co.,Inc. The vaccine is a component of Merck's three-virus MMR vaccine.... |
Jeryl Lynn Jeryl Lynn Jeryl Lynn are strains of mumps virus used in the Mumpsvax mumps vaccine made by Merck. The strains are named after Jeryl Lynn Hilleman. In 1963 Ms. Hilleman's father Dr. Maurice Hilleman, was leading efforts to produce a mumps vaccine for Merck... (B level) strain |
||
| Rubella Rubella Rubella, commonly known as German measles, is a disease caused by the rubella virus. The name "rubella" is derived from the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is... |
Meruvax II | Wistar RA 27/3 strain of live attenuated rubella virus | WI-38 human diploid lung fibroblasts | MEM (solution containing buffered salts, fetal bovine serum, human serum albumin and neomycin, etc.) |
MMR II is supplied freeze-dried (lyophilized) and contains live viruses. Before injection it is reconstituted with the solvent provided.
The MMR vaccine is administered by a subcutaneous injection
Subcutaneous injection
A subcutaneous injection is administered as a bolus into the subcutis, the layer of skin directly below the dermis and epidermis, collectively referred to as the...
.The second dose may be given as early as one month after the first dose. The second dose is not a booster
Booster dose
In medicine, a booster dose is an extra administration of a vaccine after an earlier dose. After initial immunization, a booster injection or booster dose is a re-exposure to the immunizing antigen. It is intended to increase immunity against that antigen back to protective levels after it has been...
; it is a dose to produce immunity in the small number of persons (2–5%) who fail to develop measles immunity after the first dose. In the U.S. it is done before entry to kindergarten
Kindergarten
A kindergarten is a preschool educational institution for children. The term was created by Friedrich Fröbel for the play and activity institute that he created in 1837 in Bad Blankenburg as a social experience for children for their transition from home to school...
because that is a convenient time.
Safety
Adverse reactionsAdverse drug reaction
An adverse drug reaction is an expression that describes harm associated with the use of given medications at a normal dosage. ADRs may occur following a single dose or prolonged administration of a drug or result from the combination of two or more drugs...
, rarely serious, may occur from each component of the MMR vaccine. 10% of children develop fever, malaise
Malaise
Malaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...
and a rash 5–21 days after the first vaccination; 5% develop temporary joint pain
Arthralgia
Arthralgia literally means joint pain; it is a symptom of injury, infection, illnesses or an allergic reaction to medication....
. Older women appear to be more at risk of joint pain, acute arthritis
Arthritis
Arthritis is a form of joint disorder that involves inflammation of one or more joints....
, and even (rarely) chronic arthritis. Anaphylaxis
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...
is an extremely rare but serious allergic reaction to the vaccine. One cause can be egg allergy
Egg allergy
Egg allergy is a type of food allergy. It is a hypersensitivity to dietary substances from the yolk or whites of eggs, causing an overreaction of the immune system which may lead to severe physical symptoms for millions of people around the world....
. The vaccine product brief lists many other possible adverse reactions.
The number of reports on neurologic disorders is very small, other than evidence for an association between a form of the MMR vaccine containing the Urabe mumps strain and rare adverse events of aseptic meningitis
Aseptic meningitis
Aseptic meningitis, or sterile meningitis, is a condition in which the layers lining the brain, meninges, become inflamed and a pyogenic bacterial source is not to blame. Meningitis is diagnosed on a history of characteristic symptoms and certain examination findings...
, a transient mild form of viral meningitis. The UK National Health Service
National Health Service
The National Health Service is the shared name of three of the four publicly funded healthcare systems in the United Kingdom. They provide a comprehensive range of health services, the vast majority of which are free at the point of use to residents of the United Kingdom...
stopped using the Urabe mumps strain in the early 1990s due to cases of transient mild viral meningitis, and switched to a form using the Jeryl Lynn
Jeryl Lynn
Jeryl Lynn are strains of mumps virus used in the Mumpsvax mumps vaccine made by Merck. The strains are named after Jeryl Lynn Hilleman. In 1963 Ms. Hilleman's father Dr. Maurice Hilleman, was leading efforts to produce a mumps vaccine for Merck...
mumps strain instead. The Urabe strain remains in use in a number of countries; MMR with the Urabe strain is much cheaper to manufacture than with the Jeryl Lynn
Jeryl Lynn
Jeryl Lynn are strains of mumps virus used in the Mumpsvax mumps vaccine made by Merck. The strains are named after Jeryl Lynn Hilleman. In 1963 Ms. Hilleman's father Dr. Maurice Hilleman, was leading efforts to produce a mumps vaccine for Merck...
strain, and a strain with higher efficacy
Efficacy
Efficacy is the capacity to produce an effect. It has different specific meanings in different fields. In medicine, it is the ability of an intervention or drug to reproduce a desired effect in expert hands and under ideal circumstances.- Healthcare :...
along with a somewhat higher rate of mild side effects may still have the advantage of reduced incidence of overall adverse events.
The Cochrane Library review found that, compared to placebo, MMR vaccine was associated with fewer upper respiratory tract infections, more irritability, and a similar number of other adverse effects. The review also found several problems in the quality of MMR vaccine safety studies, and recommended the adoption of standardized definitions of adverse events. The review's abstract concludes, "The design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate. The evidence of adverse events following immunisation with MMR cannot be separated from its role in preventing the target diseases."
Claims about autism
In the UKUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, the MMR vaccine was the subject of controversy after publication of a 1998 paper by Andrew Wakefield
Andrew Wakefield
Andrew Wakefield is a British former surgeon and medical researcher, known as an advocate for the discredited claim that there is a link between the measles, mumps and rubella vaccine, autism and bowel disease, and for his fraudulent 1998 research paper in support of that claim.Four years after...
et al. reporting a study of twelve children who had bowel symptoms along with autism
Autism spectrum
The term "autism spectrum" is often used to describe disorders that are currently classified as pervasive developmental disorders. Pervasive developmental disorders include autism, Asperger syndrome, Childhood disintegrative disorder, Rett syndrome and Pervasive Developmental Disorder Not Otherwise...
or other disorders, including cases where onset was believed by the parents to be soon after administration of MMR vaccine. In 2010, Wakefield's research was found by the General Medical Council
General Medical Council
The General Medical Council registers and regulates doctors practising in the United Kingdom. It has the power to revoke or restrict a doctor's registration if it deems them unfit to practise...
to have been "dishonest", and The Lancet
The Lancet
The Lancet is a weekly peer-reviewed general medical journal. It is one of the world's best known, oldest, and most respected general medical journals...
fully retracted the original paper. The research was declared fraudulent in 2011 by the British Medical Journal
British Medical Journal
BMJ is a partially open-access peer-reviewed medical journal. Originally called the British Medical Journal, the title was officially shortened to BMJ in 1988. The journal is published by the BMJ Group, a wholly owned subsidiary of the British Medical Association...
. Several subsequent peer-reviewed studies have failed to show any association between the vaccine and autism.
The Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
, the Institute of Medicine
Institute of Medicine
The Institute of Medicine is a not-for-profit, non-governmental American organization founded in 1970, under the congressional charter of the National Academy of Sciences...
of the National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
, the UK National Health Service
National Health Service
The National Health Service is the shared name of three of the four publicly funded healthcare systems in the United Kingdom. They provide a comprehensive range of health services, the vast majority of which are free at the point of use to residents of the United Kingdom...
and the Cochrane Library review have all concluded that there is no evidence of a link between the MMR vaccine and autism.
Administering the vaccines in three separate doses does not reduce the chance of adverse effects, and it increases the opportunity for infection by the two diseases not immunized against first. Health experts have criticized media reporting of the MMR-autism controversy for triggering a decline in vaccination rates. Before publication of Wakefield's findings, the inoculation rate for MMR in the UK was 92%; after publication, the rate dropped to below 80%. In 1998, there were 56 measles cases in the UK; by 2008, there were 1348 cases, with 2 confirmed deaths.
In Japan, the MMR vaccination has been discontinued, with single vaccines being used for each disease. Rates of autism diagnosis have continued to increase, showing no correlation with the change.
MMRV vaccine
The MMRV vaccine, a combined measles, mumps, rubella and varicella vaccine, has been proposed as a replacement for the MMR vaccine to simplify administration of the vaccines. Preliminary data indicate a rate of fever-induced seizureFebrile seizure
A febrile seizure, also known as a fever fit or febrile convulsion, is a convulsion associated with a significant rise in body temperature...
of 9 per 10,000 vaccinations with MMRV, as opposed to 4 per 10,000 for separate MMR and varicella injections; U.S. health officials therefore do not express a preference for use of MMRV vaccine over separate injections.