From Nature magazine
Vaccines are largely safe, and do not cause autism or diabetes, the US Institute of Medicine (IOM) said in a report issued today. This conclusion followed a review of more than 1,000 published research studies.
"We looked very hard and found very little evidence of serious adverse harms from vaccines," says Ellen Wright Clayton, chairwoman of the reporting committee and director of the Center for Biomedical Ethics and Society at Vanderbilt University in Nashville, Tennessee. "The message I would want parents to have is one of reassurance."
The report, commissioned in 2009 by the US Health Resources and Services Administration, covers the eight vaccines that comprise the majority of claims filed with the National Vaccine Injury Compensation Program (VICP), which compensates people for adverse health effects from any of 11 vaccines.
The eight vaccines under review were those for chickenpox; influenza; hepatitis B; human papillomavirus; diphtheria, tetanus and pertussis (DTaP); measles, mumps and rubella (MMR); hepatitis A; and meningococcal disease.
According to the report, evidence "convincingly supports a causal relationship" for only 14 specific adverse effects, including a range of infections associated with the chickenpox vaccine; brain inflammation and fever-induced seizures related to the MMR vaccine; allergic reactions to six of the vaccines and fainting or local inflammation caused by injection of any of them. The report noted that many of the more serious events, such as those linked to the chickenpox and MMR vaccines, only occur in children with weakened immune systems.
The report also includes less-convincing evidence of links between four other adverse events and particular vaccines.
On 135 other possible links between the vaccines and adverse effects, the panel concluded that there was "inadequate evidence to accept or reject a casual relationship".
The VICP could use this information to update its Vaccine Injury Table, which already includes most, but not all, of the adverse effects listed in the IOM report.
The committee found that evidence "favors rejection" of discredited reports that have linked the MMR vaccine to autism and, along with the DTaP vaccine, to type 1 diabetes.
"We found five really solid epidemiological reports that were very clear that MMR is not associated with autism, and does not cause autism," Wright Clayton says.
Previous IOM reports have reached the same conclusion, and a 1998 paper by Andrew Wakefield — a UK surgeon who has now been struck off the medical register — that posited a link between vaccines and autism was retracted last year by The Lancet . The journal noted that "several elements" of the original paper were "incorrect". But some parents who still believe there is a connection refuse or delay vaccinations for their children, leading to outbreaks of diseases such as measles and whooping cough.
"For those parents who are on the fence, this will be another piece of reassuring evidence, although I don't know how many more pieces of reassuring evidence you need," says Paul Offit, chief of the infectious diseases division of The Children's Hospital of Philadelphia in Pennsylvania. "For those who are committed to the concept that vaccines are harmful independent of what the data say, it won't matter."