A recently published article in the journal Pediatrics on a study conducted by experts at UCLA, Boston Children's Hospital and Rand Corp. reviews more than 60 scientific medical studies of vaccine safety and concluded that while there is some evidence of "adverse effects" from 11 vaccines, problems are "extremely rare" and that "the benefits of childhood immunizations far outweigh the risks."
The Center of Disease Control (CDC) agreed and called vaccines one of the greatest public health developments of the last century for their role in eradicating smallpox and controlling polio, measles, rubella and other infections diseases in the United States. "Parental refusal of vaccines has contributed to outbreaks of vaccine-preventable diseases such as measles and pertussis" the study authors wrote. Medical experts estimate that vaccines prevent more than 40,000 premature childhood deaths and 20 million illnesses every year.
Here is what the researches reported about each vaccine:
DTaP: The vaccine against diptheria toxoid, tetanus toxoid and acellular pertussis does not cause type 1 diabetes, according to the available evidence. Likewise, there’s no evidence to suggest the DTaP vaccine causes any other medical conditions.
Hib: The Haemophilus influenzae type b vaccine can cause redness and swelling but not high fevers, diarrhea, fungal infections, gastroesophageal reflux disease, convulsions or other conditions serious enough to require hospitalization.
Hepatitis A: One of the studies reviewed demonstrated a "moderate association" between this vaccine and purpura, a short-term condition in which leaky blood vessels cause purple spots to appear on the skin. The link was found only in children between the ages of 7 and 17.
Hepatitis B: A 2010 study reported a heightened risk of autism for boys who got this vaccine in their first month of life, but it had methodological flaws that left the authors of the new report unconvinced. They also said that the evidence suggests there is no link between this vaccine and new or relapsing cases of multiple sclerosis. However, children who are sensitive to yeast did have an increased risk of anaphylaxis.
Inactivated polio virus: Although one study found that children who got this vaccine as newborns had a heightened risk of food allergies, the authors of the new report found the evidence too weak to be conclusive.
Influenza: Most studies find no link between flu vaccines and any adverse events, though a few did reveal that kids who got a flu shot (either the live attenuated vaccine that is given through the nose and the inactivated vaccine that’s injected into muscle) were more likely than kids who didn’t to develop short-term gastrointestinal problems like diarrhea and vomiting. In addition, young children who got the inactivated vaccine had a small increased risk of febrile seizures, especially when they got their flu shots along with the pneumococcal vaccine.
MMR: The vaccine against measles, mumps and rubella does not cause autism, the report authors wrote. However, some versions the vaccine have been linked to an increased risk of febrile seizures, short-term joint pain and purpura.
Meningococcal: The vaccine against meningococcal disease can cause anaphylaxis in children who are allergic to its ingredients, the research team found. However, there is no link between the vaccine and fevers, malaise, hives, muscle pain, headache, changes in eating habits, severe irritability, persistent crying or severe sleepiness.
PCV13: The vaccine against 13 pneumococcal strains does seem to increase the risk of febrile seizures, especially when given in conjunction with a flu shot.
Rotavirus: The primary risks associated with the Rotarix or RotaTeq vaccines were cough, runny nose and irritability. The report authors found moderately strong evidence that the vaccine is linked to intussusception, “a serious disorder in which part of the intestine slides into an adjacent part of the intestine” like a telescope, according to the Mayo Clinic. However, these adverse events are “extremely rare,” according to the Pediatrics report.
Varicella: The Institute of Medicine report said this vaccine can cause children to get viruses that cause chickenpox or shingles; those infections can progress to pneumonia, meningitis, hepatitis, encephalitis or anaphylaxis. In addition, the researchers found evidence that the vaccine can cause purpura in children between the ages of 11 and 17.