Check out this answer from Consensus:
The fear that multiple vaccines might overload the immune system is not supported by scientific evidence. While certain combinations of vaccines can interfere with each other, this does not equate to immune overload. The infant immune system is capable of handling multiple vaccines, and the benefits of vaccination far outweigh the risks. Healthcare providers should continue to educate parents about the safety and efficacy of combined vaccines to alleviate their concerns.
The administration of multiple vaccines to infants and children has been a topic of concern for many parents and healthcare providers. The fear that multiple vaccines might overwhelm or weaken the immune system has led to hesitancy and calls for single antigen vaccines. This article aims to explore whether these concerns are supported by scientific evidence.
Parental Concerns
Parental concerns about vaccine overload are not new. A study conducted with British parents revealed that many are worried about the ability of their child’s immune system to handle combined vaccines. These concerns are often based on the perceived risks associated with both the diseases and the vaccines themselves1. Despite these fears, there is no scientific evidence to support the notion that combined vaccines cause immune overload1.
Immune System Capacity
The infant immune system is more robust than many parents believe. Research has shown that infants have a significant capacity to respond to multiple vaccines. Theoretically, an infant’s immune system can handle thousands of vaccines at once due to the vast number of immune cells present in the body2. Additionally, infants today encounter fewer antigens in vaccines than they did decades ago, further reducing the likelihood of immune overload2.
Vaccine Interference
While the immune system can handle multiple vaccines, there is evidence that certain combinations of vaccines can interfere with each other. For instance, vaccines that share common protein components, such as tetanus toxoid, can result in reduced antibody responses when administered simultaneously3. This phenomenon, known as epitopic overload, suggests that the immune response to one vaccine component can be suppressed by the presence of another4. However, this does not imply that the immune system is overwhelmed, but rather that the formulation of vaccines needs careful consideration.
Clinical Evidence
Several studies have investigated the clinical outcomes of administering multiple vaccines. A long-term study on the Measles, Mumps, and Rubella (MMR) vaccine found no increase in bacterial or viral infections following vaccination, suggesting that the immune system is not compromised by the combined vaccine6. Another study confirmed that the MMR vaccine did not increase the risk of hospitalizations due to invasive bacterial infections, further debunking the myth of immunological overload7.
Chronic Conditions and Immune Overload
There is some evidence linking vaccine-induced immune stimulation with chronic conditions such as type 1 diabetes and metabolic syndrome. A review suggested that the epidemic of these conditions might be related to immune overload from vaccines, although this theory remains controversial and is not widely accepted in the scientific community8.
Do multiple vaccines overload the immune system?
Ella Hulsey has answered Extremely Unlikely
An expert from University of Tennessee in Vaccinology, Nursing
According to a 2002 study, a baby could theoretically respond to 10,000 vaccines at once (Offit et al.), and a 2009 study found that children were no more likely to be hospitalized for a serious infection in the months following MMR vaccination than other children (Stowe et al.).
Offit, P. A., Quarles, J., Gerber, M. A., Hackett, C. J., Marcuse, E. K., Kollman, T. R., … Landry, S. (2002). Addressing Parents’ Concerns: Do Multiple Vaccines Overwhelm or Weaken the Infant’s Immune System? Pediatrics, 109(1), 124-129. doi: 10.1542/peds.109.1.124
Stowe, J., Andrews, N., Taylor, B., & Miller, E. (2009). No evidence of an increase of bacterial and viral infections following Measles, Mumps, and Rubella vaccine. Vaccine, 27(9), 1422-1425. doi: 10.1016/j.vaccine.2008.12.038
Do multiple vaccines overload the immune system?
Gideon Meyerowitz-Katz has answered Extremely Unlikely
An expert from University of Wollongong in Epidemiology, Public Health, Diabetes
The vaccine schedule has been carefully designed to minimize any complications, either from vaccines or preventable disease. That being said, even when kids get multiple vaccines at the same time, they still are receiving fewer pathogens than from their usual daily exposure from things like unwashed hands and other kids’ sneezing.
Do multiple vaccines overload the immune system?
Michael Head has answered Extremely Unlikely
An expert from University of Southampton in Infectious diseases, Vaccines, Global Health, Public Health, Epidemiology
In addition to Ella Hulsey’s answer and citations, this new 2019 paper covers this topic (See the PDF at the link below, and the ‘too many vaccines too soon?’ paragraph.
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciz135/5316263
There are further references to several studies at that link. This statement is one typically raised by anti-vaccine communities without any evidence to back up their assertion. Research has been carried out on this topic, and shows very clearly that there is no evidence of vaccines causing an ‘overloaded’ immune system.
Do multiple vaccines overload the immune system?
Carlo A Liverani has answered Unlikely
An expert from University of Milan in Gynaecology, Oncology
Only theoretically, but never in my experience.
In fact vaccines cannot be delayed, cause benefits overwhelm potential disadvantages.