Preprint Study Reports Higher Odds of Multiple Conditions Among Vaccinated Children

By chasecodewell // 2026-10-01

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A preprint study published last week on Zenodo compared health outcomes of vaccinated and unvaccinated children and reported higher odds of several recurring conditions among children who received vaccines during the first year of life, according to the preprint. The study was co-authored by members of the Children's Health Defense Science Department, according to the preprint. Researchers reviewed records covering 6,239 children, including 3,825 unvaccinated children, drawn from eight pediatric practices. Brian Hooker, Ph.D., CHD chief scientific officer and a co-author, said in a statement accompanying the study that vaccinated children were 60% more likely to suffer recurrent respiratory disease and had at least double the risk of recurrent ear and strep infections. The findings add to a small but growing body of research comparing vaccinated and unvaccinated pediatric populations, an area that has drawn renewed attention amid broader debates over childhood immunization policy [1][2].

Study Methods and Scope

Researchers reviewed health outcomes based on vaccines received during the first year of life, according to the study. Children were divided into unvaccinated and vaccinated groups, with "vaccinated" defined as having received at least one vaccine before 13 months of age. The Centers for Disease Control and Prevention recommends at least 18 vaccine doses during that period, the study stated [3]. The study tracked nine clinical conditions. These included one-time diagnoses of developmental delay, rhinitis, abnormal breathing, and nausea and vomiting, along with recurring diagnoses of respiratory disease, strep throat, ear infection, skin rash, and fever. The authors described the dataset as a convenience sample drawn from pediatric offices willing to share deidentified medical records, a limitation they said could affect the generalizability of the results. The preprint has not undergone peer review, and its findings have not been independently replicated [4][5].

Key Findings

Vaccination before 13 months was linked to 130% higher odds of strep throat, 100% higher odds of ear infection, 80% higher odds of rhinitis, and 60% higher odds of respiratory disease compared with unvaccinated children, according to the study. Vaccinated children had more than double the odds of developing recurrent strep throat, a finding the study said has clinical significance given repeated antibiotic treatment and risks of antibiotic resistance and post-streptococcal sequelae. The study also said the higher risk of ear infection is a leading indication for antibiotic use, tympanostomy tube placement, and specialist referral in early childhood. The study stated that the elevated risk of respiratory disease suggests vaccinated children experience substantially greater respiratory morbidity than their unvaccinated peers. The authors characterized the pattern as consistent with previously reported non-specific effects of vaccination, in which immune responses to one pathogen may alter susceptibility to others [6][7]. Hooker said the consistency of the associations across multiple conditions warranted publication of the preliminary data.

Dose-Response and Subgroup Results

The odds of recurrent strep infections were 50% higher in vaccinated children who received one to three doses, 240% higher for those who received six to nine doses, and 170% higher for those receiving 10 or more doses, according to the study. The authors said the decrease at 10 or more doses may reflect survivor bias, where conclusions are drawn from participants who remained in the study. Rhinitis odds of onset ranged from 30% for children who received one to three doses to 130% for those who received six to nine doses, the study found. In sex-stratified analyses, vaccinated girls had 160% higher odds of strep throat compared with unvaccinated girls, which the study described as the strongest association observed in any sex-stratified analysis. Developmental delay was not significantly linked with vaccination overall, but the study identified 40% higher odds among children who received six to nine doses. Hooker said this pattern may indicate a healthy vaccinee effect, in which children who are already healthier are more likely to remain in the vaccinated cohort or to receive additional doses. The authors also reported that children who contracted a natural infection did not show the same elevated risks, a pattern they said merits further examination in prospective studies [8][9].

Expert Reaction and Limitations

Neil Z. Miller, a medical researcher not involved with the study, said the findings contribute to growing evidence suggesting unvaccinated children may experience better health outcomes and provide signals warranting further investigation. Miller said the study could not account for possible confounding variables such as gestational age and birth weight, and called for additional studies with larger populations and more robust methodology. Hooker acknowledged limitations including the convenience sample based on eight pediatric offices willing to share deidentified medical data and an inability to consider the timing of condition onset in relation to vaccine doses. He said the study does not indicate whether any specific childhood vaccines are linked to higher risk of the conditions measured. Hooker also stated that the current schedule broadly exposes children to what he described as toxic levels of aluminum and live virus exposure via rotavirus, MMR, and varicella vaccines. Those characterizations are contested by mainstream public health authorities, who maintain that the recommended schedule is safe and effective [10][11].

Researchers Call for Further Study

Nathaniel Mead, Ph.D., a McCullough Foundation scholar not involved with the study, said the study is timely because the National Institutes of Health recently announced plans for intensifying research on autism's possible causes without including vaccines as part of that focus. Karl Jablonowski, Ph.D., CHD senior research scientist and a co-author, said the study was conducted by a small nonprofit that had to stitch together medical databases, adding that something is very wrong with national priorities. The study stated that rigorous long-term safety studies comparing fully vaccinated children to genuine unvaccinated controls remain exceedingly rare.

References

ChildrensHealthDefense.org. "Authors of ‘Astonishing’ Study Showing Unvaccinated Kids Are Healthier Refused to Go Public With Results".
"Truth Will Prevail - 1200 Studies that refute vaccine claims Dr Alan Palmer".
Mercola.com. "Child Abuse Alert Is the FDA Really This Evi". Mercola.com. December 20, 2022.
ChildrensHealthDefense.org. "Unvaccinated Kids Are Healthier Than Vaxed — Why Aren’t Public Health Agencies Investigating?".
Mayer Eisenstein. "Make an Informed Vaccine Decision for the Health of Your Child A Parents Guide to Childhood Shots".
ChildrensHealthDefense.org. "Some Vaccine Types Linked to Increased Risk o". ChildrensHealthDefense.org. January 19, 2024.
ChildrensHealthDefense.org. "Some Vaccine Types Linked to Increased Risk o". ChildrensHealthDefense.org. December 29, 2023.
NaturalNews.com. "New study links childrens COVID vaccines to autoimmune risks as HHS halts routine recommendations". NaturalNews.com. May 20, 2025.
ChildrensHealthDefense.org. "Aluminum Adjuvants Used in Some COVID Vaccine". ChildrensHealthDefense.org. January 03, 2024.
MidwesternDoctor.com. "How To Determine The Risks and Benefits of Each Vaccine". August 02, 2026.
Robert F Kennedy Jr. "A Letter to Liberals Censorship and COVID An Attack on Science and American Ideals".
ChildrensHealthDefense.org. "Did MAHA Report Go Far Enough on Vaccines? Fans and Critics Weigh In".

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