- Years ago, her neighbor lost a baby to sudden infant death syndrome (SIDS) right after the child was vaccinated.
- She did get a vaccination for her oldest child, and he had a febrile seizure afterward, which she blames on the vaccination.
I'll address each point.
1) Any SIDS death is tragic and too often unexplained. However, research statistics indicate that SIDS risk is neither increased nor decreased by vaccination. (https://www.ncbi.nlm.nih.gov/pubmed/22289512) SIDS appears correlated with breathing difficulties, particularly those related to mild upper respiratory infections and cigarette smoke (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1619535/?page=1, https://www.nichd.nih.gov/sts/campaign/science/Pages/causes.aspx). Per the CDC, upper respiratory infections are not common side effects of any childhood vaccinations:
Do you know what apparently can be a good source of upper respiratory infections? Going to the pediatrician's office, where there is a good chance of finding rhinovirus-shedding children. (http://www.today.com/moms/taking-your-healthy-kids-doctor-may-make-them-sick-2D12110565, https://www.ncbi.nlm.nih.gov/pubmed/20135827) Thus, regardless of vaccination, simply having gone to the pediatrician recently might conceivably have increased the chance of SIDS for my relative's neighbor's child.
2) A febrile seizure is associated with having a fever. ("Febrile" means having a fever.) Febrile seizures are relatively common, affecting up to 6.7% of children. (https://www.ncbi.nlm.nih.gov/pubmed/16510738) The fever after an immunization is a result of an immune response to the partial, weakened, or dead bacteria or viruses in the vaccine. Fever is a common side effect of nearly every available vaccine. (https://www.cdc.gov/vaccines/vac-gen/side-effects.htm). That is because fevers are part of a functioning immune system, and moderate fevers help save our lives when fighting infections. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786079/) Febrile seizures are more likely right after vaccinations (although not delaying vaccinations in toddlers results in a lower risk of febrile seizures: http://pediatrics.aappublications.org/content/pediatrics/early/2014/05/14/peds.2013-3429.full.pdf), but getting the vaccine-preventable illness is far more likely to result in febrile seizures if H1N1 is representative of what happens with infections generally. (https://www.ncbi.nlm.nih.gov/pubmed/26073015, https://www.ncbi.nlm.nih.gov/pubmed/26553258) If one is certain that children will never encounter a vaccine-preventable illness, it is rational to not get the vaccine. But when is something like that certain? If one is wrong, and the child's immune system has to fight off the illness, there will likely be worse consequences--including febrile seizures--than the child would have suffered from the vaccine.
So is my relative right to treat vaccines as something she should avoid? Well, not with respect to the SIDS argument. But avoiding immunizations for her children probably has decreased the incidence of fevers and febrile seizures for her children, for she keeps a clean house and they haven't come down with measles, mumps, rubella, polio, etc. Their not having come down with vaccine-preventable diseases, however, is a result of her living in the USA, her own caution, and good luck. Next week a recently arrived traveler from Chicago could bring mumps to a school in her area, and her sons could end up with meningitis or decreased fertility as a result. I don't think her risk-benefit analysis has led her to the best decision for her family because she is unaware of how easily vaccine-preventable diseases can be brought to her orderly doorstep.