An observational analysis of medical records from eight pediatric practices found associations between vaccination before 13 months and higher recorded odds of several recurrent infectious and respiratory conditions, while researchers and outside commentators acknowledged limitations that prevent firm causal conclusions.

By yourNEWS Media Newsroom

A new preprint comparing health outcomes among vaccinated and unvaccinated children has reported higher odds of several recurrent infectious, respiratory and other diagnoses among children who received at least one vaccine before 13 months, findings the authors say warrant additional investigation into the overall health effects of early childhood vaccination.

The study, released in late September on the Zenodo research repository, analyzed medical records for 6,239 children from eight pediatric practices. Of those children, 3,825 were classified as unvaccinated, while the remainder had received at least one vaccine before reaching 13 months of age.

Read the full study: Comparative Health Outcomes Vaccinated vs Unvaccinated Children 9 26 26

Several of the study’s authors are members of the Children’s Health Defense Science Department, including Brian Hooker, Ph.D., the organization’s chief scientific officer. The researchers examined diagnoses recorded in the children’s medical files and compared outcomes according to whether children had received vaccines during their first year and, separately, according to the number of vaccine doses recorded.

The study is observational, and its design cannot by itself establish that vaccination caused the health differences it identified. The authors and researchers commenting on the paper acknowledged limitations including the use of a convenience sample, the inability to account for some potentially important confounding factors and a lack of information establishing precisely when diagnoses occurred in relation to individual vaccine doses.

Still, Hooker said the size of the unvaccinated group made the dataset notable compared with previous vaccination research.

“Children were 60% more likely to suffer recurrent respiratory disease with at least double the risk of recurrent ear and strep infections,” Hooker said. “In general, the risk increased in the vaccinated group based on increasing number of vaccines received.”

Among the principal findings reported by the researchers, vaccination before 13 months was associated with 130% higher odds of recurrent strep throat, 100% higher odds of recurrent ear infections, 80% higher odds of rhinitis and 60% higher odds of recurrent respiratory disease when compared with children classified as unvaccinated.

The researchers also reported what they called “a clear dose-response gradient” for recurrent strep infections, with the estimated odds generally rising as the number of vaccine doses increased.

Medical researcher Neil Z. Miller, who was not involved in the research, said the results add to evidence he believes deserves further examination.

Miller said the findings suggest that “unvaccinated children may experience better health outcomes than vaccinated children.” He also said they “provide important signals that warrant further investigation.”

Researchers examined nine health outcomes

Rather than evaluating a single disease or developmental outcome, the researchers looked for nine different clinical diagnoses appearing in the children’s medical records.

One-time diagnoses included developmental delay, rhinitis, abnormal breathing, nausea and vomiting.

The researchers separately examined recurrent respiratory disease, strep throat, ear infections, skin rash and fever. For the recurring conditions, the study defined recurrence as three separate diagnoses recorded within a 12-month period.

Children were classified as vaccinated if their records showed at least one vaccine before 13 months. That definition means the vaccinated group encompassed children with widely different levels of vaccine exposure, from those receiving only a few doses to those receiving substantially more.

The researchers therefore conducted an additional analysis based on the number of doses received.

The submitted study summary contrasts that exposure with the CDC childhood immunization schedule, which it states calls for at least 18 vaccine doses during the period examined, depending on the vaccines and schedule followed.

The study’s central comparison was not between children receiving different vaccine brands or schedules. It instead compared children with no documented vaccination before 13 months against those who had received one or more doses.

Recurrent strep showed one of the strongest associations

Recurrent strep throat produced some of the study’s largest reported differences.

Children in the vaccinated group overall had more than twice the odds of recurrent strep compared with unvaccinated children, according to the researchers.

The authors described that result as “a finding with clinical significance given the need for repeated antibiotic treatment and the associated risks of antibiotic resistance, microbiome disruption, and rare but serious post-streptococcal sequelae.”

The dose analysis showed additional variation.

Compared with unvaccinated children, the reported odds of recurrent strep were approximately 50% higher among children receiving one to three vaccine doses. The estimated increase reached 240% among children receiving six to nine doses.

Among children who had received 10 or more doses, the estimated increase declined to approximately 170% compared with the unvaccinated group.

The researchers said that decline at the highest exposure level “may reflect survivor bias,” referring to a form of bias that can occur when people who remain represented in a dataset differ systematically from those who do not.

That explanation is an interpretation offered by the study’s authors rather than a finding demonstrating why the pattern occurred.

Ear infections were another prominent result. The study reported approximately twice the odds of recurrent ear infections among vaccinated children.

The researchers noted that recurrent childhood ear infection is “a leading indication for antibiotic use, tympanostomy tube placement, and specialist referral in early childhood.”

Recurrent respiratory disease was approximately 60% more likely in the vaccinated group under the study’s statistical analysis. The authors wrote that the finding “suggests that vaccinated children experience substantially greater respiratory morbidity than their unvaccinated peers.”

Those associations do not determine why the diagnoses differed between the two groups, an issue that would require further research capable of addressing alternative explanations and potential confounding variables.

Rhinitis and developmental delay also examined

The study reported approximately 80% higher odds of rhinitis among vaccinated children overall.

When researchers examined the finding by number of doses, the estimated odds were approximately 30% higher among children receiving one to three doses and climbed to approximately 130% higher among children receiving six to nine doses, compared with unvaccinated children.

The authors described the dose-response results across several health conditions as “compelling evidence” supporting further investigation.

Developmental delay produced a different pattern.

The researchers did not identify a statistically significant increase in developmental delay across the vaccinated population as a whole. An elevated association emerged only within one of the higher-exposure groups examined in the dose analysis, where the reported odds were approximately 40% above those of the unvaccinated children.

Hooker suggested one possible explanation for the absence of a significant overall association could involve what researchers call the “healthy vaccinee” effect.

He described it as a situation “where parents of children developing more slowly, especially at younger ages, avoid vaccinations.”

That explanation remains a hypothesis rather than something established by the study.

Girls showed a larger association for recurrent strep

Researchers also analyzed some outcomes by sex and reported that vaccinated girls had approximately 160% higher odds of recurrent strep throat than unvaccinated girls.

The paper characterized that result as “the strongest association observed in any sex-stratified analysis” conducted by the researchers.

Epidemiologist M. Nathaniel Mead, Ph.D., a McCullough Foundation scholar who was not involved in the research, said the diagnostic patterns should be examined further for possible immune-system effects.

“The fact that kids who received at least one vaccine before 13 months were more often coded for several common infectious and respiratory diagnoses suggests an effect on the immune system,” Mead said.

The study itself does not demonstrate a biological mechanism linking vaccination to the recurrent diagnoses, and the researchers did not identify individual vaccines as being responsible for any particular outcome.

Authors focus on recurring illness rather than isolated diagnoses

Hooker said one of the distinguishing features of the research was its emphasis on conditions occurring repeatedly rather than exclusively measuring whether a child had ever received a particular diagnosis.

“The primary thrust of the study: recurring disease in children has been studied only peripherally in the past, despite strong evidence that vaccines and vaccine components can negatively impact the immune system,” Hooker said.

He said recurring infections could potentially reflect “innate immune suppression.”

Hooker added that the findings “affirm this evidence as well as the need for additional study to understand the role of vaccines in recurrent infections and the extent that this is harming our population in the U.S.”

Those statements reflect Hooker’s interpretation of the results. The study did not establish that immune suppression caused the differences recorded in the medical data.

Hooker also argued that directly comparing vaccinated and unvaccinated children provides information that can be missed when researchers compare groups that have all received vaccines but differ in timing or number of doses. He characterized the latter approach as “a methodological choice that systematically masks vaccine-associated morbidity.”

The researchers said the number of vaccine doses administered during infancy and childhood has increased substantially since the early 1990s, while writing that “rigorous long-term safety studies comparing fully vaccinated children to genuine unvaccinated controls remain exceedingly rare.”

Study has several important limitations

Both the authors and outside commentators identified limitations that complicate interpretation of the findings.

The medical records came from eight pediatric practices willing to provide deidentified data rather than from a randomly selected nationally representative population. Hooker acknowledged that the project therefore relied on a convenience sample.

That sampling method raises the possibility that patients attending those practices differ in meaningful ways from the broader U.S. child population.

The study also could not determine the timing of every diagnosis relative to every vaccine dose. That limits the researchers’ ability to establish whether exposure consistently preceded the condition being analyzed, an essential consideration in evaluating potential causal relationships.

Miller noted additional variables the analysis could not fully address, including gestational age and birth weight.

“Additional studies with larger populations and more robust methodology are needed before firm conclusions can be drawn,” Miller said.

The research also did not determine whether any specific vaccine was associated with higher odds of any particular diagnosis. Children in the vaccinated group may have received different combinations and numbers of vaccines, preventing the study from attributing an observed association to one vaccine product.

The authors’ statistical associations therefore should not be interpreted as demonstrating that a particular childhood vaccine caused strep throat, ear infections, respiratory disease, rhinitis, developmental delay or the other outcomes analyzed.

Researchers call for broader examination of the childhood schedule

Hooker said he believes the new analysis supports what he described as a significant body of literature examining what he characterizes as the risks of vaccination, including among partially vaccinated children.

He also pointed to a 2011 Institute of Medicine publication that evaluated evidence concerning numerous potential vaccine adverse events. The publication found that evidence was inadequate in some instances to accept or reject a causal relationship, depending on the vaccine and condition examined.

Hooker raised separate questions about components and technologies used across the current vaccination schedule.

“The current schedule includes significant exposure to toxic levels of aluminum, which we know can travel to multiple organs in the body, including the brain. In addition, live virus exposure via rotavirus, measles-mumps-rubella (MMR) and varicella vaccines occurs throughout the first year of life,” Hooker said.

The present study, however, did not test whether aluminum or another vaccine component caused the reported health differences.

Outside researchers urge additional study rather than firm conclusions

Miller said the methodological limitations make replication and stronger research designs important before the findings are treated as definitive.

He said that, despite those limitations, “the findings provide important signals that warrant further investigation.”

Mead similarly described the research as “timely,” pointing to recent discussion surrounding the National Institutes of Health and research into possible causes of autism.

Mead said NIH “recently announced plans for intensifying research on autism’s possible causes, without including vaccines as part of that focus.”

“Clearly we need to better understand the total health impacts of the current vaccine schedule,” Mead said.

Karl Jablonowski, Ph.D., a CHD senior research scientist and study co-author, said the project demonstrates that direct comparisons involving large numbers of unvaccinated children can be assembled from pediatric medical records even without the resources available to major government agencies and health systems.

“The largest such study was not conducted with millions of taxpayer dollars, HMO data and by decree from the NIH. It was done by a small, unyielding non-profit that had to stitch together medical databases,” Jablonowski said, referring to CHD.

“Something is very wrong with our national priorities, and our children are suffering because of it.”

The study’s authors are calling for additional research capable of addressing the unanswered questions raised by their analysis, including larger populations, stronger control of confounding variables, more precise timing of vaccine exposure and diagnosis, and examination of individual vaccines or combinations.

For now, the findings represent associations reported in an observational preprint rather than proof that childhood vaccination caused the conditions identified. The size of the unvaccinated comparison group and the reported dose-related patterns give researchers specific hypotheses to test, while the study’s sampling, timing and confounding limitations remain central to determining how broadly its results can be applied.

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