That report found vaccines can cause certain side effects but serious ones are very rare. “Concerns about vaccine safety have led some parents to decline recommended vaccination of their children, leading to the resurgence of diseases,” RAND’s Dr. Courtney Gidengil and colleagues wrote in their report, published in the journal Pediatrics. The report says there is "strong evidence" that the measles vaccine is not associated with an increased risk of autism. "There is a lot of misinformation out there about vaccines," says co-author Margaret Maglione, also a researcher with Rand. Like all drugs, vaccines can cause serious side effects. “We found evidence that some vaccines are associated with serious adverse events; however, these events are extremely rare and must be weighed against the protective benefits that vaccines provide.” The worst adverse events include a very rare intestinal blockage called intussusception caused by the rotavirus vaccine and a rare blood disorder called thrombocytopenic purpura linked with the chickenpox and measles, mumps and rubella (MMR) vaccine. In an April report, the CDC noted that vaccines given to infants and young children over the past two decades will prevent 322 million illnesses, 21 million hospitalizations and 732,000 deaths over the course of their lifetimes. The new report notes that some vaccines, including flu shots and the combined vaccine against measles, mumps and rubella, are associated with an increased risk of fever-related seizures in small children. Although these seizures can be frightening for parents, they're typically benign and cause no long-term problems. According to the analysis, vaccines against rotavirus – a common cause of severe diarrhea and dehydration in children – increase the risk of a serious type of intestinal blockage called intussusception, in which part of the intestine telescopes into itself. The vaccines against it, RotaTeq and Rotarix, can cause an additional one to five cases of intussusception for every 100,000 doses given, the analysis says. The new analysis looked at dozens of medical studies completed since the 2011 report.
– Another day, another study asserting that vaccines don't cause autism: This time, researchers analyzed 67 different studies and found no evidence that immunizations cause autism. "There is a lot of misinformation out there about vaccines," a co-author tells USA Today. "With the rise of the Internet and the decline of print journalism, anyone can put anything on the Internet." The new report finds "strong evidence" that the measles-mumps-rubella vaccine, implicated in an increased risk of autism in a since-retracted 1998 study, is not associated with such a risk. The study also found no proof vaccines cause childhood leukemia, the AP reports, and that in general, side effects from vaccines are "extremely rare." While some vaccines, including the MMR vaccine and the flu shot, can cause an increased risk of fever-related seizures in small children, those seizures are typically benign. The most serious side effects (an intestinal blockage caused by the rotavirus vaccine and a blood disorder linked to the chickenpox and MMR vaccines) are both rare, NBC News reports. Ultimately, the study concludes, the benefits of vaccines outweigh the small risks. And, to put those risks in perspective, one expert notes, "The most dangerous aspect of giving your child vaccines is driving to the office to get them."