A 2013 Institute of Medicine (IOM) study reaffirmed that serious vaccine adverse reactions can occur but are very rare and usually minor.
The most common vaccine side effects among young children and newborns include swelling, redness, and a small hard lump at the injection site. These vaccine reactions usually subside within in a couple of days. More severe vaccine injuries, such as an allergic reaction to a vaccine, occur in less than one in a million cases.
When a person encounters a pathogen, such as those found in common vaccines, there is no way to tell whether it will induce a mild or severe form of the disease and how the immune system will react, according to Scientific American. Environmental exposures, immune deficiencies and genetic variations contribute to how the body will react to the vaccine.
Most people will benefit from immunization. However, there is a rare chance a person may develop a serious vaccine injury such as Guillain-Barre syndrome (GBS). GBS is a serious autoimmune disorder that can render a once healthy person paralyzed and helpless. Guillain Barre flu shot injuries are extremely rare, but very possible side effects.
The IOM study examined eight common childhood vaccines and potential reactions, including the measles-mumps-rubella (MMR) vaccine. Children have a one in 3,000 chance of developing febrile seizures from the MMR vaccine. In most cases, these seizures will not lead to any permanent neurological damage. However, there are very rare cases were a child may suffer encephalopathy and experience permanent brain damage from the MMR vaccine.
Debilitating vaccine injuries are extremely rare. Failing to immunize because of vaccine injury fears puts the child at a more formidable risk and leaves them vulnerable to contracting a potentially lethal disease. There is also the potential to set off an outbreak if they come in contact with other unvaccinated children, according to Scientific American. “Protecting kids actually helps protect everyone.”