After analyzing over 1,000 research papers, a report issued by the IOM (Institute of Medicine) found no evidence linking vaccines to autism or type 1 diabetes risk, and very few other health problems caused or clearly linked to vaccines. According to a committee of experts who reviewed the scientific studies, convincing evidence was found of 14 health outcomes associated with vaccines, including fainting, brain inflammation and seizures, however, their occurrences were found to be very rare.
Some less clear data linking certain vaccines to four other effects, including temporary joint pain and allergic reactions were also found. Regarding other suggested adverse effects, the experts said there was inadequate data.
The IOM says that this review will help the HHS administer the VICP (Vaccine Injury Compensation Program), which depends on science-based evidence when deciding on vaccine-related side effects. The HHS (Department of Health and Human Services) asked the IOM for a comprehensive review on eight vaccines covered by VICP.
The HHS says the findings of the review are helpful for VICP staff, special masters that rule on vaccine cases, those filing claims, and others.
MMR (measles-mumps-rubella) vaccine - some people may have seizures caused by fever. In virtually all cases, the effect was temporary and without long-term consequences. Very rarely, those with severe immune deficiencies may develop a form of brain inflammation. Some women and children may experience short-term pain.
Varicella (chickenpox) vaccine - in rare cases some people may have brain swelling, pneumonia, meningitis, shingles, and hepatitis, and also chickenpox if the patient has a weakened immune system.
Anaphylaxis - this is an allergic reaction. Anaphylaxis can occur shortly after receiving the MMR, Varicella, influenza, hepatitis B, meningococcal, and the tetanus-containing vaccines (all injections). The HPV vaccine may trigger anaphylaxis in some patients.
The report also explained that vaccines in general can cause some individuals to faint, while others may develop inflammation of the shoulder. Some evidence points towards four other adverse events with some vaccines, however, the evidence is not compelling, the authors explained.
Some people who have received the influenza vaccine abroad have developed mild, temporary oculo-respiratory syndrome, with signs and symptoms such as facial swelling, conjunctivitis and mild respiratory signs.
The following vaccines were found not to be linked to the following four conditions:
- MMR and DTaP (diphtheria-tetanus-acellular pertussis) - do not cause diabetes type 1
- MMR - does not cause autism
- The flu vaccine - does not exacerbate asthma or cause Bell's palsy
Solid evidence is required in order to establish a cause-and-effect relationship between an agent and a health outcome. The committee reviewed several kinds of evidence, such as clinical, biological, and epidemiological research. Suggested vaccine-related adverse outcomes in most cases are not backed by proper evidence, or when evidence was found, it was contradicted by conflicting results, making it impossible to draw any conclusions, the experts wrote.
Committee chair Ellen Wright Clayton, said:
"With the start of the new school year, it's time to ensure that children are up to date on their immunizations, making this report's findings about the safety of these eight vaccines particularly timely. The findings should be reassuring to parents that few health problems are clearly connected to immunizations, and these effects occur relatively rarely. And repeated study has made clear that some health problems are not caused by vaccines."
Written by Christian Nordqvist