VaccineOverloadVaccine overload is the term used when the vaccine may cause effectsuch as overwhelm or weaken a child’s immature immune system after they were giventhe vaccination which its objective is to prevent from infection and lead toadverse effects. Despite scientific evidence that strongly contradicts thisidea, some parents of autistic children believe that vaccine overload causesautism. The resulting controversy has caused many parents to delay or avoidimmunizing their children. Such parental misperceptions are major obstaclestowards immunization of children. With the increase in the number of vaccines over recent decades,improvements in vaccine design have reduced the immunologic load from vaccines.The total number of immunological components in the 14 vaccines administered toUS children in 2009 is less than 10% of what it was in the 7 vaccines given in1980. A study published in 2013 found no correlation between autism and the antigennumber in the vaccines the children were administered up to the age of two. Ofthe 1,008 children in the study, one quarter of those diagnosed with autismwere born between 1994 and 1999, when the routine vaccine schedule couldcontain more than 3,000 antigens (in a single shot of DTP vaccine).
The vaccine schedule in 2012 contains several more vaccines, but the number of antigensthe child is exposed to by the age of two is 315. Vaccines pose a very smallimmunologic load compared to the pathogens naturally encountered by a child ina typical year; common childhood conditions such as fevers and middle-earinfections pose a much greater challenge to the immune system thanvaccines, and studies have shown that vaccinations, even multiple concurrentvaccinations, do not weaken the immune system or compromise overall immunity.The insufficient of the evidence which supports the vaccine overload hypothesis,combined with these findings, has led to the sum up that currently recommendedvaccine programs do not cause “overload” or weaken the immune system.Any experiment based on withholding vaccines from children hasbeen considered unethical, and observational studies would likely be confoundedby differences in the health care-seeking behaviours of under-vaccinatedchildren. Thus, no study directly comparing rates of autism in vaccinated andunvaccinated children has been done. However, the concept of vaccine overloadis biologically not seeming reasonable or acceptable.
The vaccinated andunvaccinated children have the same immune response to non-vaccine-relatedinfections, and autism is not an immune-mediated disease, so it is claimed thatvaccines could cause it by overloading the immune system is against currentknowledge of the pathogenesis of autism. So, the idea thatvaccines can cause autism has been effectively eliminated by the weight ofcurrent evidence. Prenatal InfectionThereis evidence that schizophrenia is associated with prenatalexposure to rubella,influenza,and toxoplasmosisinfection. For example, a study found an increased risk of schizophrenia whenmothers were exposed to influenza in the first trimester of gestation. This mayhave public health implications, as strategies for preventing infection includevaccination, simple hygiene, and, in the case of toxoplasmosis, antibiotics.Based on studies in animal models, theoretical concerns have been raised abouta possible link between maternal immune response activated by virus antigens andschizophrenia. A review done in 2009 concluded that there was insufficientevidence recorded to recommend routine use of trivalentinfluenza vaccine during the first trimester of pregnancy, but thevaccine was still recommended other time from the first trimester and inspecial or certain circumstances.
It is recommended to have routine flu shotsfor pregnant women (recommendation from the CDC’s (Centersfor Disease Control and Prevention in Atlanta)Advisory Committee on ImmunizationPractices, the AmericanCollege of Obstetricians and Gynecologists, and the American Academy of Family Physicians),for several reasons: their risk for serious influenza-related medical complications during the last two trimesters;their greater rates for flu-related hospitalizations compared to non-pregnant women;the possible transfer of maternal anti-influenza antibodies to children, protecting the children from the flu; andseveral studies that found no harm to pregnant women or their children from the vaccinations.