[Note: AAP = American Academy of Pediatrics; CDC = Centers for Disease Control; VAERS = Vaccine Adverse Event Reporting System]
From the CDC's Vaccine Information Sheet:
HealthCentral provides a picture of the rash.
From the Nelson Textbook of Pediatrics, 16th edition:
From the AAP Red Book:
From the CDC's Vaccine Information Sheet:
From the Nelson Textbook of Pediatrics, 16th edition:
From the AAP Red Book:
From the CDC's Vaccine Information Sheet:
HealthCentral provides a picture of the rash.
From the Nelson Textbook of Pediatrics, 16th edition:
From the AAP Red Book:
The AAP recommended vaccination schedule:
"The 2nd dose of measles, mumps, and rubella (MMR) vaccine is recommended routinely at 4 to 6 years of age but may be administered during any visit, provided at least 4 weeks have elapsed since receipt of the 1st dose and that both doses are administered beginning at or after 12 months of age. Those who have not previously received the second dose should complete the schedule by the 11- to 12-year-old visit."
Most children acquire some natural immunity to measles from their mothers in utero. This "passive immunity" fades over time, and is less effective in children of immunized mothers than in children of mothers who had the measles (which is very few mothers these days). Here's some research results on the topic:
LE Markowitz, P Albrecht, P Rhodes, R Demonteverde, E Swint, EF Maes, C Powell and PA Patriarca, "Changing levels of measles antibody titers in women and children in the United States: impact on response to vaccination" (Pediatrics 1996 97:53-58): Study of roughly 1000 children and mothers before and after vaccination with either monovalent measles or MMR vaccines. "The response to the vaccines varied by maternal birth year for children of women born in the United States. Among 9- month-old children, 93% of those whose mothers were born after 1963 responded, compared with 77% and 60% of those whose mothers were born in 1957 through 1963 and before 1957, respectively. Among 12-month-old children, 98% of those born to the youngest mothers responded, compared with 90% and 83% of those whose mothers were born in 1957 through 1963 and before 1957. The responses of children of women born outside of the United States were not associated with maternal year of birth. CONCLUSIONS. An increasing proportion of children in the United States will respond to the measles vaccine at younger ages because of lower levels of passively acquired maternal measles antibodies."
YA Maldonado, EC Lawrence, R DeHovitz, H Hartzell and P Albrecht, "Early loss of passive measles antibody in infants of mothers with vaccine-induced immunity" (Pediatrics 1995 96:447-450): Tested maternal and infant immunity at birth, 9, and 12 months. 71% of the 9-month infants and 95% of the 12-month infants had no detectable measles antibodies. "All infants with detectable measles antibody at 9 or 12 months had mothers born before 1963, before the vaccine era, and both material and cord blood measles geometric mean titers decreased significantly with decreasing maternal age. CONCLUSIONS. Persistence of passive measles antibody is uncommon by 12 months of age; earlier antibody loss is related to lower maternal age and maternal measles titer."
Mark Papania, Andrew L. Baughman, Susan Lee, James E. Cheek, §, William Atkinson, , Stephen C. Redd, Kenneth Spitalny, Lyn Finelli, and Lauri Markowitz, "Increased Susceptibility to Measles in Infants in the United States" (Pediatrics 1999 104:e59): Study of 128 non-vaccinated infants exposed to measles. "Infants whose mothers were born after 1963 had a measles attack rate of 33%, compared with 12% for infants of older mothers....Most infants are protected from measles by passively acquired maternal antibody from birth until the antibody is depleted. The duration of protection is dependent to a great extent on the amount of antibody received by the infant during pregnancy, which is directly related to the maternal antibody titer. Women who have had measles disease have high measles antibody titers, women who have not had measles but have been vaccinated effectively have lower antibody titers, and women who have neither had measles nor been vaccinated effectively have no measles antibody."
Bottom line: vaccinated mothers pass on immunity to measles, but this immunity does not last as long as that passed on by mothers who had the measles. But in any case this maternally-derived immunity is almost always gone by 12-15 months.
As a historical note, the original recommended age for the measles vaccination was 15 months, to ensure that the maternal antibodies were gone (otherwise they might attack the vaccine before it could provoke more antibodies); as a result of this and other research, that was lowered to 12 months, since almost all infants now in the USA are born to mothers who did not have the measles.
The CDC lists reasons not to vaccinate:
Note that there are other conditions that should be evaluated before any vaccination. For example, HIV-positive children or those undergoing treatment for cancer should discuss any vaccinations with their physicians. In general, vaccines should only be given after a review of the child's history and current condition.
The CDC's numbers on vaccine reactions:
As a parent, you have the right to see the product insert from any vaccine that's going to be given to your child, and I urge you to exercise that right. Be prepared for a lot of very tiny print. The product insert for Merck M-M-R II vaccine (the only combined MMR currently licensed in the United States) is available online.
By the way, make sure you ask for the vaccine insert when you're talking to the folks at your doctor's office. You want the paper full of tiny print from the manufacturer that gets shipped with the vaccine. Several times I have had well-meaning nurses bring me the sheet of information from the CDC instead, which is a simplified summary that leaves out a lot of information. If the print is big enough to read without a magnifying glass, it's the wrong thing.
M-M-R II is a mix of three of Merck's vaccines: Attenuvax (measles), Mumpsvax (mumps), and Meruvax II (rubella). The three vaccines are available separately, though it may cost you more to order them that way. Some people recommend administering separate vaccines, but I haven't been able to find any studies indicating better results or less side effects if you go that route, and it does mean more shots for your child.
"Each dose of the vaccine is calculated to contain sorbitol (14.5 mg), sodium phosphate, sucrose (1. 9 mg), sodium chloride, hydrolyzed gelatin (14.5 mg), human albumin (0.3 mg), fetal bovine serum (<1 ppm), other buffer and media ingredients and approximately 25 mcg of neomycin. The product contains no preservative."
This means that M-M-R II does not contain any mercury, which has been a hot topic lately. However note the possibility of a problem if your child is highly allergic to eggs, neomycin or gelatin.
Merck passes on some numbers on vaccine effectiveness:
"The impact of measles, mumps, and rubella vaccination on the natural history of each disease in the United States can be quantified by comparing the maximum number of measles, mumps, and rubella cases reported in a given year prior to vaccine use to the number of cases of each disease reported in 1995. For measles, 894,134 cases reported in 1941 compared to 288 cases reported in 1995 resulted in a 99.97% decrease in reported cases; for mumps, 152,209 cases reported in 1968 compared to 840 cases reported in 1995 resulted in a 99.45% decrease in reported cases; and for rubella, 57,686 cases reported in 1969 compared to 200 cases reported in 1995 resulted in a 99.65% decrease."
The vaccine insert lists quite a few reported adverse reactions. However, it does not give any information on the frequency with which these reactions have been reported. And remember, just because someone reports a reaction doesn't mean the vaccine had anything to do with it. In any case, here's the list:
"Experience from more than 80 million doses of all live measles vaccines given in the U.S. through 1975 indicates that significant central nervous system reactions such as encephalitis and encephalopathy, occurring within 30 days after vaccination, have been temporally associated with measles vaccine very rarely. 54 In no case has it been shown that reactions were actually caused by vaccine. The Centers for Disease Control and Prevention has pointed out that "a certain number of cases of encephalitis may be expected to occur in a large childhood population in a defined period of time even when no vaccines are administered". However, the data suggest the possibility that some of these cases may have been caused by measles vaccines. The risk of such serious neurological disorders following live measles virus vaccine administration remains far less than that for encephalitis and encephalopathy with natural measles (one per two thousand reported cases)."
"There have been reports of subacute sclerosing panencephalitis (SSPE) in children who did not have a history of natural measles but did receive measles vaccine. Some of these cases may have resulted from unrecognized measles in the first year of life or possibly from the measles vaccination. Based on estimated nationwide measles vaccine distribution, the association of SSPE cases to measles vaccination is about one case per million vaccine doses distributed. This is far less than the association with natural measles, 6-22 cases of SSPE per million cases of measles. The results of a retrospective case-controlled study conducted by the Centers for Disease Control and Prevention suggest that the overall effect of measles vaccine has been to protect against SSPE by preventing measles with its inherent higher risk of SSPE.""Death from various, and in some cases unknown, causes has been reported rarely following vaccination with measles, mumps, and rubella vaccines; however, a causal relationship has not been established. No deaths or permanent sequelae were reported in a published post-marketing surveillance study in Finland involving 1.5 million children and adults who were vaccinated with M-M-R II during 1982-1993."
The first shot is recommended for 12-15 months (there is evidence that immunization at 6 months does not work as well), and the second shot at 4-6 years (though some jurisdictions have more specific requirements). The shot should be administered under the skin on the outside of the upper arm, not to a vein or muscle.
They don't recommend getting MMR at the same visit as DTaP or OPV (but your kids shouldn't be getting OPV anyhow if you're in the USA).
The vaccine should be stored in a dark place between 36 and 46 degrees Fahrenheit -- in other words, in the refrigerator.
The National Vaccine Information Center is probably the largest anti-vaccination group around. They seem to be opposed to the MMR vaccine (though it's hard to find a page where they come right out and say so) based on the proposed association between MMR and autism (which I'll discuss below). They call for more research on the subject.
VaccineWebsite.com collects a wide variety of somewhat disorganized information about many vaccines, including the MMR vaccine. They have much on the possibility of autism, suggest that measles deaths can be prevented by proper sanitation without vaccination, claim measles can be cured with Vitamin A and C injections, and blame a cartel of governments and businesses for hyping the MMR vaccine to make money. They also make statements like "Measles was never a problem to naturopaths who maintain it is the method used by the body to eliminate toxins, mostly produced by our high starch diet" and support other fringe theories.
Randall Neustaedter's The Vaccine Guide: Making an Informed Choice (see my review) recommends against all forms of measles, mumps, and rubella vaccination. He feels the reported vaccine reactions are more serious than the diseases, though he nowhere attempts to estimate anything like relative risks. In fact, he completely ignores the fact that measles itself used to kill children. He also pronounces a faith in the efficacy of homeopathic treatments to prevent side effects if a child comes down with these diseases, which is nonsense.
Unvaccinated Children discusses homeopathic treatments for childhood diseases, including measles, mumps, and rubella.
Certainly the most mainstream of all anti-vaccination activism right now is centered around a possible association between the MMR vaccination and autism. There is a great deal of information out there on this topic. Fortunately many of the original sources are available online, so it's not necessary to rely on summaries (even mine; if you're worried, please follow up by reading the medical research).
Much of the debate on whether there is an association between the MMR vaccine and autism has taken place in the pages of the British medical journal The Lancet. Although The Lancet is online, their site is maddeningly unfriendly: you must go through a free registration process to access it at all, and it is impossible to link to individual articles. So I'm going to provide quick summaries of as much of the debate as I can find here, along with traditional citations. These articles are all available on their web site, but you'll have to use the search page to find them (a search on the terms "mmr autism" will bring up all of the articles summarized here).
Because of the Lancet's (lack of) organization on its web site, I may have missed a few articles in the controversy. If you run across a citation not mentioned here, I'd love to know about it.
You should also read the excellent summary of the debate over Wakefield's findings available from the Autism Autoimmunity Project. It includes a slightly different take on the research in The Lancet, as well as notes on papers published in other medical journals.
Another pair of researchers who looked at a possible connection are Vijendra Singh and Victor Yang of the University of Michigan's College of Pharmacy. They published a paper in October 1998 in Clinical Immunology and Immunopathology looking at the levels of some antibodies in autistic children compared to non-autistic children. The journal article is not available online, but you can read the press release or an article in Science Daily. Here's the conclusion from the press release:
"The strongest link found in the autistic children was between measles virus antibodies and anti-MBP [an antibody to brain tissue], suggesting that exposure to the measles virus may trigger an autoimmune response that interferes with the development of myelin, says Singh. If myelin in the brain doesn't develop properly, nerve fibers won't work as they should. This could be one way that the brain abnormalities associated with autism arise.
"The question of how exposure to measles virus occurs raises a controversial issue. Parents of children with autism often report that the children started showing signs of the disorder shortly after being immunized with measles-mumps-rubella (MMR) or diphtheria-pertussis-tetanus (DPT) vaccine, but no scientific studies have shown a link between vaccines and autism. In the U-M study, almost all the subjects had had MMR immunizations, and none had ever had a case of measles. It is possible, however, that some might have been infected with measles virus but never developed symptoms of measles, says Singh."
Wakefield has published another paper in Adverse Drug Reactions and Toxicological Reviews 19:4, alleging that the MMR vaccine was licensed in the UK based on faulty safety reviews. I have not yet been able to find a copy of this paper on the web, but the UK Medicines Control Agency (MCA) has published a response. They stop just short of accusing Wakefield of fraud: "The paper by Dr Wakefield does not present any new data - it merely reviews a number of published articles. It is highly selective as opposed to the scientific standard of being systematic, and studies that do not support the author’s views are not mentioned. No search for all relevant publications has been done. It is easy for scaremongering to sap public confidence by biased presentations that are contrary to the large amount of data that provide real reassurance."
BMJ published a paper in February 2001 titled "Mumps, measles, and rubella vaccine and the incidence of autism recorded by general practitioners: a time trend analysis". The authors examined British medical records covering roughly 3 million person-years of pediatric practice. They found that, in the 1988-93 period, there was a steady rise in autism diagnoses, while the rate of MMR vaccination remained steady. From their paper:
"Results The incidence of newly diagnosed autism increased sevenfold, from 0.3 per 10 000 person years in 1988 to 2.1 per 10 000 person years in 1999. The peak incidence was among 3 and 4 year olds, and 83% (254/305) of cases were boys. In an annual birth cohort analysis of 114 boys born in 1988-93, the risk of autism in 2 to 5 year old boys increased nearly fourfold over time, from 8 (95% confidence interval 4 to 14) per 10 000 for boys born in 1988 to 29 (20 to 43) per 10 000 for boys born in 1993. For the same annual birth cohorts the prevalence of MMR vaccination was over 95%.
"Conclusions Because the incidence of autism among 2 to 5 year olds increased markedly among boys born in each year separately from 1988 to 1993 while MMR vaccine coverage was over 95% for successive annual birth cohorts, the data provide evidence that no correlation exists between the prevalence of MMR vaccination and the rapid increase in the risk of autism over time. The explanation for the marked increase in risk of the diagnosis of autism in the past decade remains uncertain."
By examining successive birth cohorts individually, this paper avoids some of the methodological problems of the paper by Taylor et al mentioned above. However, it is certainly not the last word on the subject. You should read the Rapid Response letters published on the BMJ web site as well as the original paper. Some of these responses are shoddy, but the one from Mark Berelowitz (who was involved with the original Wakefield study) deserves attention:
"Let us look at it differently. The authors claim to have evidence that the incidence has risen seven fold in ten years (from 0.3 to 2.1 cases per 10 000 person years). Projecting this forward, by the year 2040 the incidence will be 5000 per 10000 person years, and soon thereafter every child born will develop autism. Alternatively, this is a dramatic blip, covering just a 10 year period only, and the increase will not continue. In that case the blip can only be explained by an environmental cause.
"Either their autism data is flawed, or there is an important environmental pathogen that can cause temporary fluctuations in the incidence of autism, or the world is facing an epidemic which will make HIV and BSE seem like small problems."
A March 7, 2001 article in the Journal of the American Medical Association also comes out against the linkage between measles and autism. I have not seen the full article, but the abstract is available online. The authors performed a statistical analysis of data from California between 1980 and 1994. They find a startling rise in autism diagnoses, but only a small rise in MMR coverage. Their conclusion:
"These data do not suggest an association between MMR immunization among young children and an increase in autism occurrence."
A March 2001 article in Archives of Pediatrics & Adolescent Medicine examined the other part of Wakefield's original study: the proposed link between MMR and IBD. Once again the full article is for paying subscribers only, but the abstract is online. The study examined 155 children with IBD and matched them with control patients by sex, HMO, and birth year. They then looked at whether vaccination with MMR or another measles-containing vaccine (MCV) was associated with an increased risk of IBD. Their conclusion:
Results Past vaccination was not associated with an increased risk for Crohn's disease (odds ratio [OR] for measles-mumps-rubella vaccine [MMR], 0.4; 95% confidence interval [CI], 0.08-2.0), ulcerative colitis (OR, 0.8; 95% CI, 0.18-3.56), or IBD (OR, 0.59; 95% CI, 0.21-1.68). Risk for IBD was not increased among children vaccinated who were younger than 12 months (OR for MMR, 0.61; 95% CI, 0.15-2.45) or aged 12 to 18 months (OR, 0.86; 95% CI, 0.28-2.59) relative to unvaccinated children. Children vaccinated with MMR who were older than 18 months were at significantly decreased risk for IBD (OR, 0.16; 95% CI, 0.04-0.68). Neither past vaccination nor age at vaccination with other MCV was associated with increased risk for Crohn's disease, ulcerative colitis, or IBD. Risk for Crohn's disease, ulcerative colitis, or IBD was not elevated in the time immediately following vaccination with either vaccine.
Conclusions Vaccination with MMR or other MCV, or the timing of vaccination early in life, did not increase the risk for IBD.
Looking at their numbers, in fact, vaccination with MMR past the age of 18 months actually decreased the risk of IBD.
Also in March 2001, the Institute of Medicine's Immunization Safety Review Committee held a meeting to review the current state of research in MMR and autism. You can download PowerPoint slides, audio presentations, and other materials from the meeting, which included Dr. Wakefield and some of his critics as well as researchers from the CDC and elsewhere.
And in April 2001, the Institute of Medicine's Immunization Safety Review Committee released their Immunization Safety Review: Measles-Mumps-Rubella Vaccine and Autism (available online in OpenBook or PDF formats). In addition to reading the report online, you can also read a four-page summary. The summary points out the lengths to which the IOM went in convening this committee:
"To preclude any real or perceived conflicts of interest, candidate members were subject to strict selection criteria that excluded anyone who had participated in research on vaccine safety, received funding from vaccine manu-facturers or their parent companies, or served on vaccine advisory committees."
After spending over a year reviewing the evidence, the committee came to four basic conclusions. First, they found no support in the data for an association on the population level between MMR and ASD (autistic spectrum disorders). That is, the relationship some researchers see between the introduction of MMR and a rise in ASD rates does not hold up. Second, they criticized Wakefield's original work:
"Second, the committee concluded that the case series of children with ASD and bowel symptoms (Wakefield et al., 1998) is uninformative with respect to causality between MMR and ASD. The small number of cases, the potential selection bias, the difficulty in diagnosing children with ASD, multiple diagnoses in the patients, and the lack of detail regarding the criteria for the behavioral diagnoses of the children in the series limit the utility of this study in establishing causality. Although parents or doctors made a temporal link between the onset of their children’s behavioral disorders and the MMR vaccine, the authors of the resulting paper acknowledge that their findings do not prove an association between MMR and the condition they describe. Furthermore, it is not possible to describe from this study the nature of any relationship among vaccine-strain measles virus infection, ASD, and bowel symptoms."
Third, they found that no convincing biological mechanism has been proposed to explain any relationship between MMR and ASD. Fourth, they found no animal research models that could be used to illuminate the proposed MMR-ASD relationship. Their final conclusion:
"Thus, the Committee concludes that the evidence favors rejection of a causal relation-ship at the population level between MMR vaccine and autistic spectrum disorders (ASD). The committee bases this conclusion on the following evidence: · A consistent body of epidemiological evidence shows no association at a population level between MMR vaccine and ASD. · The original case series of children with ASD and bowel symptoms and other available case reports are uninformative with respect to causality. · Biologic models linking MMR vaccine and ASD are fragmentary. · There is no relevant animal model linking MMR vaccine and ASD. However, the committee notes that its conclusion does not exclude the possibility that MMR vaccine could contribute to ASD in a small number of children, because the epidemiological evidence lacks the precision to assess rare occurrences of a response to MMR vaccine leading to ASD and the proposed biological models linking MMR vaccine to ASD, although far from established, are nevertheless not disproved."
That conclusion bears careful examination. Although the epidemiological evidence does rule out a widespread causal relationship between MMR and ASD, it does not rule out the possibility that there might be an effect in some children at a level too low to be seen in population statistics. The committee recommended some specific further research be pursued to investigate this possibility:
- Use accepted case definitions and assessment protocols for ASD to enhance the precision and comparability of results from surveillance, epidemiological studies, and biologic investigations.
- Explore whether exposure to MMR vaccine is a risk factor for ASD in a small number of children.
- Develop targeted investigation of whether or not measles vaccine-strain virus is present in the intestines of some children with ASD.
- Encourage all who submit reports to the Vaccine Adverse Event Reporting System to provide as much detail and as much documentation as possible when any diagnosis of ASD is thought to be related to MMR vaccine.
- Study the possible effects of different immunization exposures—for example, studying children whose families have chosen to have them not receive the MMR vaccine.
- Conduct further clinical and epidemiological studies of sufficient rigor to identify risk factors and biological markers of ASD in order to better understand genetic or environmental causes.
The May 2001 issue of Pediatrics (the AAP magazine) includes an article "Measles-Mumps-Rubella Vaccine and Autistic Spectrum Disorder: Report From the New Challenges in Childhood Immunizations Conference Convened in Oak Brook, Illinois, June 12-13, 2000" (If you can't get to that link, you should at least be able to get the abstract). This is the final report on a detailed review of all the evidence to date on the connection between MMR and autism. They discuss individual claims in detail and cite over 200 references, but their conclusion is simple:
"Although the possible association with MMR vaccine has received much public and political attention and there are many who have derived their own conclusions based on personal experiences, the available evidence does not support the hypothesis that MMR vaccine causes autism or associated disorders or IBD. Separate administration of measles, mumps, and rubella vaccines to children provides no benefit over administration of the combination MMR vaccine and would result in delayed or missed immunizations. Pediatricians need to work with families to ensure that children are protected early in the second year of life from these preventable diseases. Continued scientific efforts need to be directed to the identification of the causes of ASD."
We have now reached the point where review articles are appearing. One is by Benjamin Estrada, MD, from the University of South Alabama. In MMR and Autism: Suspect or Superstition? he reviews the major studies and then writes
"It is very difficult to diagnose autism in the first year of life. Since MMR is usually administered to children after their first birthday, the diagnosis of this condition may occur temporally close to the vaccine administration, but there is no evidence to support a causal association between them. In addition, current data suggest a lack of correlation between the rates of MMR vaccine administration and the increase in the number of cases of autism observed during the last 20 years. Although the cause for the increase in the incidence of this disorder is not known (the apparent increase might simply be the result of increased awareness), mounting evidence suggests that immunization with MMR vaccine should eventually be excluded from the list of 'usual suspects.'"
After reviewing the evidence to date, a panel of the Canadian Paediatric Society (CPS) concluded in June 2001:
"The Canadian Paediatric Society (CPS) supports the conclusions reached by other groups that the evidence available internationally to date does not support an association between MMR vaccination and the development of autism."
Another review article appeared in Archives of Disease in Childhood in October 2001. The conclusion of the article, titled MMR vaccine -- worries are not justified, is unequivocal:
"There is no good scientific evidence to support a link between MMR vaccine and autism or inflammatory bowel disease; indeed there is mounting evidence that shows no link. There is considerable evidence of the effectiveness and safety of MMR vaccine. Using separate vaccines is an untried and untested policy and, as far as protecting children from infectious disease is concerned, a backward step.
"While the final decision rests with the parents, the evidence of the safety and efficacy of MMR vaccine is so overwhelmingly conclusive that health professionals should have no hesitation in recommending its use."
The magazine adds some editorial commentary:
"The evidence relating to the inflammatory bowel disease/measles virus and autism/MMR hypotheses has been reviewed on numerous occasions by various independent expert groups, both in the UK and elsewhere. The consensus in their conclusions is remarkable. None has found any scientifically robust evidence in support of these hypotheses."
bmj.com (the electronic arm of the British Medical Journal) published a paper in February 2002 titled Measles, mumps, and rubella vaccination and bowel problems or developmental regression in children with autism: population study. This paper looks at the proposed association between MMR, autism, and bowel disease. They looked at autistic children born over a 20-year period starting in 1979, to see whether there was evidence of the supposed "new variant" form of autism. If there really was a new form of autism caused by MMR and associated with bowel disease, the authors should have seen an increased proportion of autistic children with bowel problems. They found no such increase, and conclude
"These findings provide no support for an MMR associated 'new variant' form of autism with developmental regression and bowel problems, and further evidence against involvement of MMR vaccine in the initiation of autism."
Two more epidemiological studies reported in November 2002 found no line between MMR and autism. The first study, from Pediatrics, is titled "Neurologic Disorders After Measles-Mumps-Rubella Vaccination" (that link for subscribers only; abstract is here) examined hospital records for just over half a million children in Finland who received the MMR vaccine between November 1982 and June 1986. The researchers looked for a correlation of this data with hospital discharge registers for neurologic disorders. Their conclusion:
"Linkage of vaccination records of over 500 000 children with a national hospital discharge register found no evidence of an increased risk of encephalitis or aseptic meningitis associated with MMR vaccination. On the contrary, during 1983–1985 the incidence of encephalitis of undefined cause among 1- to 7-year-old children decreased by 35% and the incidence of aseptic meningitis by 24%. This change is in concordance with the observed protective effect of MMR vaccination on encephalitis caused by measles, mumps, and rubella.27 In addition, no evidence for the hypothesized link between MMR vaccination, autism, and inflammatory bowel disease was found."
The second article, "A Population-Based Study of Measles, Mumps, and Rubella Vaccination and Autism", appeared in the New England Journal of Medicine. This one involved a study of the records of half a million Danish children who were vaccinated between 1991 and 1998. Apparently the Danes keep even more meticulous records than the Finns. The conclusion of this study is quite similar to the other:
"Of the 537,303 children in the cohort (representing 2,129,864 person-years), 440,655 (82.0 percent) had received the MMR vaccine. We identified 316 children with a diagnosis of autistic disorder and 422 with a diagnosis of other autistic-spectrum disorders. After adjustment for potential confounders, the relative risk of autistic disorder in the group of vaccinated children, as compared with the unvaccinated group, was 0.92 (95 percent confidence interval, 0.68 to 1.24), and the relative risk of another autistic-spectrum disorder was 0.83 (95 percent confidence interval, 0.65 to 1.07). There was no association between the age at the time of vaccination, the time since vaccination, or the date of vaccination and the development of autistic disorder. "
It seems clear to me that we have not heard the last word on the possible links between MMR, IBD, and autism, but that there is a firm consensus within the mainstream medical community that the proposed link has no scientific justification. The debate has been remarkably polarizing and acrimonious, with researchers on both sides of the question accusing one another of shoddy research and attempts to suppress the truth. My own personal view is that the preponderance of the evidence refutes the notion that MMR vaccination plays a causal role in either IBD or autism, and that parents can safely continue to give this vaccination to their children.