(This is the third in a four-part series. If you are just joining us, you might want to start with the introduction.)
“Because vaccines are so widely used—and because state laws require that children be vaccinated to enter daycare and school, in part to protect others—immunization safety concerns should be vigorously pursued in order to restore this trust.” IOM, 2002
As I mentioned earlier, all medical interventions have risks. MMR does have some of the more worrisome adverse effects of the vaccines we have. Some of the common ones associated with MMR include fever, rash, swelling of the lymph nodes, and inflammation of the parotid salivary gland. But these are also associated with catching the three viruses found in MMRII naturally and occur less frequently with vaccination than infection. (Remember, MMR is a live virus vaccine and so induces a very mild, non-communicable infection.) Adult women, however, are at an increased risk for adverse effects of vaccination. Up to 25% may develop joint pain that can be either transient or longer lasting.
There are people who should not get a live virus vaccine like MMR, including those with severe immune suppression. It is important to know that women who are pregnant should not receive this vaccine and all women should avoid becoming pregnant for 3 months after receiving it. Additionally, the ProQuad vaccine, that includes varicella (chickenpox) along with measles, mumps and rubella, is not recommended for breastfeeding mothers, as the varicella virus may be transmitted through breast milk. ProQuad (which includes the chickenpox vaccine) is also associated with a higher rate of fever and febrile seizures than is MMRII. I will also add that I prefer a child to be healthy, without a fever, and, if possible, not at all under the weather when receiving an immunization.
It was Andrew Wakefield’s 1998 Lancet study that started the big commotion over MMR, linking it with autism. The paper was fraudulent and has since been retracted. There are people who do not believe that Wakefield’s trial was fair and perhaps Brian Deer and the BMJ had gone after him with too much hype and vengeance. But to be honest, it doesn’t matter. I’ve read this short paper a number of times. Even if it was strictly factual and their methods were transparent (which they were not), the evidence he presented was too weak to draw any conclusions. His data does not link MMR vaccination with autism, but the media—very much encouraged by Wakefield—did. Really, it is a bad study. I don’t want to spend more time talking about autism and MMR, but if you want to learn more, check out the Yokohama study or this synopsis. I’m not an epidemiologist, but if you are, and are reading this, I’d love to hear your take on Wakefield’s response.
Autism aside, we do need more research into the safety of the measles vaccine. This was the conclusion of the highly respected Cochrane Collaboration in 2011. While they asserted that MMR is probably safe, they also admitted “the design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate.” Before you decide that is enough to stop vaccinating, know that the Cochrane investigators went on to say that the “existing evidence on the safety and effectiveness of MMR vaccine supports current policies of mass immunization aimed at global measles eradication.” So, this does not mean the vaccine is not safe. It does mean that we don’t know for sure what all the risks are. I would really like to see long-term studies on the impact of our childhood vaccination program on chronic disease. What might 30+ immunizations before the age of 6 contribute? We don’t currently know. Does this make me nervous? To be honest: a little bit, yes. But not enough to decline to vaccinate my children. Weighing the existing evidence on risks and benefits, vaccination emerges the better option.
Stay tuned, the next and final installment will get into vaccine choices and related considerations.