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Column originally published Jan 28, 2014

MMR Vaccine Does Not Cause Autism

Question: I am a first-time mother. Our daughter is seven-months-old. We have followed our family doctor’s advice to give her all the recommended vaccines. However, my best friend told me that she is not going to give her son the MMR vaccine; she said that it can cause autism. She gave me the links to several websites. After I read the information, I am really scared. What is your opinion about MMR vaccine and its connection with autism?


I am very pleased that you asked this question instead of just following your friend’s advice, or believing in what your have read on the Internet. Let me bring together the scientific information so that you can make an informed decision.

MMR is a live vaccine combining measles, mumps, and rubella viruses. Before the vaccine was widely available in North America, these viruses infected many, if not most children, in early childhood.

Measles is a particularly contagious virus. If there is a sick person with measles in a room, and if other children are not already vaccinated, almost everyone will get infected. Within a few days, they will be sick with high fever, running nose, cough, and a bad rash that starts from the face and spreads through the whole body. The most serious complications are pneumonia and encephalitis (inflammation of the brain). Before vaccine was available, many children died from pneumonia secondary to measles infection.

Mumps is primarily a viral infection of the salivary glands. In some boys and young men, it can also infect the testes and lead to reduced fertility.

Rubella causes a mild fever and rash, but it can produce devastating congenital infection in the foetus if a woman gets infected during pregnancy. The foetus can die in the womb, or can develop malformation of the heart, as well as blindness, deafness, and damage to the developing brain. Children are immunized with rubella vaccine so that they cannot spread the virus to pregnant women, and later they are protected from rubella infection while they are pregnant.

Scientists found that if they grow these viruses in tissue cultures generation after generation, they become less likely to cause an infection. Essentially, they were able to tame the viruses artificially. By growing measles, mumps, and rubella viruses separately and then mixing them together, the MMR vaccine was produced. When they injected the vaccine into test subjects, some developed a little fever and rash, but the infection was extremely mild compared with natural infection. Their immune response, however, was excellent.

The MMR vaccine was marketed in North America in 1960s. Within a few short years, the number of new cases of all three infections plummeted. Then in late 1980s, there were new outbreaks of measles in Canada and United States. Further research showed that some children had lost their immunity after a number of years. As a result, a second MMR vaccine was added for everyone to ensure good protection from all three viruses. This approach was so successful that there were very few cases reported in the 1990s throughout North America.

The controversy surrounding MMR vaccine began when Dr Andrew Wakefield, who was working in London, England, at the time, published an article in 1998, linking measles vaccine with autism in 12 children. The media picked up the story, and this raised great fear among parents all over the world, and resulted in significant decline in the number of children receiving MMR vaccine in the last decade.

In response to Dr Wakefield’s research, scientists around the world started to review their data. In the past 10 years, many research publications have found no connection between measles vaccine in MMR and autism in children. It was most interesting to note that in Japan, MMR was withdrawn from children’s vaccination program in 1993 for totally different reason, and the incidence of autism has continued to increase, therefore, disproving any association between measles vaccine and autism.

Over time, all the collaborators in Dr Wakefield’s article withdrew their support of his research. Further investigation showed that the technique that Dr Wakefield used to identify fragments of measles virus in tissue samples of these children was inaccurate, and retesting of the same samples showed no trace of measles virus at all. This finally led the prestigious journal Lancet to officially retract Dr Wakefield’s publication in 2010.

Unfortunately, Dr Wakefield continued to spread misinformation in spite of overwhelming scientific evidence against his research. Other anti-vaccination groups took up the challenge and set up numerous websites to spread false information about the vaccine. Worst of all, Jenny McCarthy, a new co-host of ABC daytime talk-show ‘The View,’ had insisted that her son’s disease was caused by MMR vaccine.

These anti-vaccination groups also claimed that a chemical called Thimerosal, a mercury-containing compound that is used in some vaccines to prevent contamination, is the cause of autism. The truth is that the MMR vaccine that has been used in Canada never contained Thimerosal, and we have children suffering from autism just like any other country.

In today’s Internet and social media world, it is very difficult to discern what is true and what is false, and where to find accurate information. Just typing “MMR vaccine and autism” in Google resulted in over 122,000 hits, no wonder many parents are confused! The only thing that I can say is that MMR vaccine is not the cause of autism in children.

With fewer children receiving MMR vaccine, outbreaks of measles and mumps are happening, and regrettably, one day, we will see babies born with congenital rubella infection, something that we have not seen for several decades.

My best advice for you is to get MMR vaccine for your daughter, and suggest that your friend to do the same for her son.