Studies show vaccines don’t cause sudden infant death syndrome

An Instagram post from July 2024 claimed that childhood vaccines cause sudden infant death syndrome (SIDS), drawing more than 7,000 likes. It also claimed that vaccines contain toxic levels of aluminum, suggesting that this is the cause of SIDS in vaccinated children. Science Feedback addressed the false claim that vaccines contain toxic levels of aluminum in previous reviews here and here.

The post was made by the Instagram accounts injecting.truth and the_tracy_lane, which have more than 31,000 followers and 158,000 followers, respectively. The account injecting.truth, which is also associated with the Instagram accounts faithful_free_momma and injecting.truth.apparel, earns commissions on Amazon from promoting supplements like colloidal silver and books containing vaccine misinformation.

The U.S. National Institutes of Health (NIH) define SIDS as “the sudden death of a baby younger than 1 year of age that doesn’t have a known cause, even after a full investigation”. Investigations involve healthcare providers as well as law enforcement, and include autopsy, examining the death scene, and reviewing clinical history.

Risk factors for SIDS include sleep surface and position, and prenatal and pregnancy factors. For example, premature babies or babies with low birth weight are at higher risk for SIDS. And babies that sleep on their stomach or on soft surfaces are at higher risk for SIDS. However, vaccination isn’t a risk factor for SIDS.

Nevertheless, the claim remains persistent, possibly because SIDS is poorly understood, making it an attractive target for vaccine misinformation. Iterations of this claim may invoke correlations between vaccines—in terms of the number of doses or timing—and SIDS to imply a causal relationship between the two, as was done in the Instagram post. At the same time, evidence that doesn’t support the claim is ignored.

We’ve addressed claims that the DTaP vaccine specifically causes SIDS in previous reviews. This review will address the broader claim that childhood vaccination causes SIDS.

Studies found no difference in SIDS incidence between unvaccinated and vaccinated infants

Conspiracy theories alleging vaccine harms are covered up or hidden are commonly promoted by those opposed to vaccination. The Instagram post similarly alleged that information about vaccines causing SIDS was being hidden, but offered no evidence for this.

Studies comparing unvaccinated infants with vaccinated infants found no difference in SIDS incidence between the two^{[1, 2]}, as the Vaccine Education Center at the Children’s Hospital of Philadelphia explained. Some studies even found that vaccinated infants were less likely to succumb to SIDS^{[3, 4]}. These findings establish that childhood vaccines don’t cause SIDS.

Unlike the Instagram post, the studies don’t rely solely on temporal correlations, but also compare the incidence of SIDS in vaccinated infants with unvaccinated infants. This is important because SIDS also occurs in unvaccinated infants. Without establishing the baseline incidence, it is impossible to determine whether SIDS is more or less common in vaccinated infants.

A 2003 review by the U.S. Institute of Medicine (now the U.S. National Academy of Medicine) looking at the safety of the U.S. childhood vaccination schedule concluded that “the evidence favors rejection of a causal relationship between exposure to multiple vaccines and SIDS”^[5].

Paper made unsubstantiated speculation that vaccines cause breathing problems

The Instagram post cited a 2004 paper from Viera Scheibner as evidence that childhood vaccines cause potentially lethal changes in breathing in infants. Scheibner is a geologist and anti-vaccination activist.

In the paper, Scheibner presented graphs of breathing patterns in two infants, measured by a machine she co-developed named Cotwatch. She alleged that these two infants exhibited what she called a “stress-induced breathing pattern” after vaccination, which didn’t occur before vaccination. She went on to speculate that this caused infant deaths after vaccination, although no evidence was presented to back up this claim.

There are a few reasons to view these claims with skepticism. Firstly, the paper contained data from just two infants. This sample size is far too small to enable an observed trend to be reliably generalized to other infants.

Secondly, Scheibner has no medical qualifications and there was no evidence showing that the standard by which she judged the infants’ breathing to be abnormal or the result of “stress” was clinically validated.

Thirdly, it’s unclear how she established with certainty that this stress—if indeed there was stress—was solely due to vaccination, when there could be other factors at play. The paper contained no information about the two infants other than that they were vaccinated at some point. As such, there’s no way to account for potential confounding factors; for example, factors that could alter breathing that are unrelated to vaccination, like certain pre-existing medical conditions.

In brief, the claim that this paper shows vaccines cause potential dangerous changes in breathing in infants is inaccurate, as the paper isn’t equipped to support this hypothesis.

In fact, a study published in 1985 investigated whether DTP vaccination was linked to breathing difficulties and SIDS using pneumograms^[6]. The authors studied 30 control infants, 46 infants with unexplained apnea, and 33 siblings of SIDS victims the night before and the night following a DTP immunization. The study found that “DTP immunization does not increase abnormalities of the ventilatory pattern […] in infants at increased risk for SIDS”.

Infant mortality study by Miller and Goldman contains flaws that cast doubt over its reliability

Another piece of evidence provided by the post is this published study from 2011 by journalist Neil Miller and computer scientist Gary Goldman. Like Scheibner, neither holds medical qualifications or relevant training. Earlier reviews from Science Feedback discussed flawed studies co-authored by Miller, which were used to prop up misinformation about vaccine safety.

In the 2011 study, Miller and Goldman correlated 2009 infant mortality rate (IMR) statistics obtained from the U.S. Central Intelligence Agency with the number of vaccine doses recommended for infants under a year old in 33 countries and the U.S. These 33 countries all had a better IMR than the U.S.

They found that there was a correlation between a higher IMR and a greater number of recommended vaccine doses. This led them to suggest vaccines as a potential cause of SIDS, and that the high IMR in the U.S. relative to these 33 countries is due to what they called “over-vaccination”.

However, the study exhibits a few problems that render its reliability questionable.

David Gorski, a surgical oncologist and an editor of Science-Based Medicine, a website that debunks health misinformation, pointed out that most infants who die before they reach a year old haven’t received most vaccines on the childhood vaccination schedule. Indeed, the World Health Organization states that “Most neonatal deaths (75%) occur during the first week of life”.

The same pattern also appears in the U.S. and has been observed since at least the middle of the last century, as a 2003 report by the U.S. Institute of Medicine (today the U.S. National Academy of Medicine) showed. The report found that in 1950, the majority of infant deaths occurred before 28 days of age; this trend was still present 20 and 40 years afterwards.

And this trend still persists. A November 2023 report from the U.S. National Vital Statistics System found that approximately 64% of infants who died under a year old did so before reaching 28 days of age in 2021. This figure was around 63% for 2022.

However, Miller and Goldman’s hypothesis rests on the assumption that most infants who died received most or all of the recommended vaccines. Since the majority of infant deaths occur before two months of age, which is when the bulk of childhood vaccinations in the U.S. begins, it’s questionable whether infant deaths are primarily due to “over-vaccination”.

Gorski also questioned why the authors chose to only compare the U.S. with the 33 countries that had better IMR:

“There is no statistical rationale for doing this, nor is there a scientific rationale. Again, if this is a true correlation, it will be robust enough to show up in comparisons of more nations than just the U.S. and nations with more favorable infant mortality rates. Basically, the choice of data analyzed leaves a strong suspicion of cherry picking.”

He also highlighted the fact that IMRs are “are very difficult to compare” between countries. One reason is because infant mortality is counted differently between countries. An article by Bernardine Healy, a former director of the NIH, explained:

“First, it’s shaky ground to compare U.S. infant mortality with reports from other countries. The United States counts all births as live if they show any sign of life, regardless of prematurity or size. This includes what many other countries report as stillbirths. In Austria and Germany, fetal weight must be at least 500 grams (1 pound) to count as a live birth; in other parts of Europe, such as Switzerland, the fetus must be at least 30 centimeters (12 inches) long. In Belgium and France, births at less than 26 weeks of pregnancy are registered as lifeless. And some countries don’t reliably register babies who die within the first 24 hours of birth. Thus, the United States is sure to report higher infant mortality rates. For this very reason, the Organization for Economic Cooperation and Development, which collects the European numbers, warns of head-to-head comparisons by country.”

Finally, there are errors in the number of doses that Miller and Goldman calculated for some of the countries, which could affect the alleged correlation they draw between IMR and vaccination. We based our findings on the vaccination schedules available in 2010, since the study used vaccination schedules from the same year.

For example, the paper claimed Germany’s childhood vaccination schedule for infants under a year old included three doses each of the DTaP, polio, Hib (Haemophilus influenzae type b), and pneumococcal vaccines. This added up to 18 doses, since the authors considered the DTaP combination vaccine to be three doses in one, so three doses of DTaP vaccine were nine vaccine doses.

But as this post pointed out, Germany’s recommended vaccination schedule for infants under a year old also included a dose of Hepatitis B vaccine and could also include the fourth doses of DTaP, Hib, and pneumococcal vaccine, since these are recommended between 11 to 14 months of age.

So if we followed Miller and Goldman’s method of counting vaccine doses, the number of doses recommended in Germany would be between 19 (if we excluded the fourth round of DTaP, Hib, and pneumococcal vaccines) and 24 (if the fourth round was included), not 18.

Another instance is the number of vaccines calculated for the Czech Republic. The authors considered this country to have recommended 19 doses: three doses each of DTaP, polio, Hib, and Hepatitis B vaccine and a dose of BCG vaccine. However, the Czech Republic also recommended, at that time, a fourth dose of DTaP, Hib, polio, and hepatitis B vaccines, for infants aged between 11 months and one week and 18 months. So infants under a year old could potentially receive 25 doses under this schedule, not 19.

Another error can be found in the number of recommended doses assigned to Switzerland; the number of pneumococcal vaccines recommended for infants under one year was two, not three, as stated in the study. The third dose was scheduled for 12 months. Based on the way Miller and Goldman counted doses for other countries, this should have been excluded from the doses for infants under one.

These mistakes in counting doses could change the correlation that they drew and in turn, the conclusions they made.

In summary, like Scheibner’s paper, Miller and Goldman’s study contains important deficiencies that cast doubt over the reliability of its conclusions.

Conclusion

Sudden infant death syndrome (SIDS) is the sudden unexpected death of an infant under a year old that doesn’t have a known cause. Exactly what causes SIDS is unknown. Among risk factors for SIDS are premature birth and low birth weight. Unsafe sleep practices that increase an infant’s risk of suffocation are also SIDS risk factors.

However, vaccines aren’t a risk factor for SIDS. We know this because multiple published studies didn’t find a greater incidence of SIDS in vaccinated infants relative to unvaccinated infants. Therefore, claims that vaccines cause SIDS are inaccurate.

REFERENCES

• 1 – Yang and Shaw. (2018) Sudden infant death syndrome, attention-deficit/hyperactivity disorder and vaccines: Longitudinal population analyses. Vaccine.
• 2 – Jonville-Béra et al. (2008) Sudden unexpected death in infants under 3 months of age and vaccination status – a case-control study. British Pharmaceutical Journal.
• 3 – Vennemann et al. (2007) Sudden infant death syndrome: No increased risk after immunisation. Vaccine.
• 4 – Fleming et al. (2001) The UK accelerated immunisation programme and sudden unexpected death in infancy: case-control study. BMJ.
• 5 – Institute of Medicine (US) Immunization Safety Review Committee; Stratton K, Almario DA, Wizemann TM, et al., editors. Immunization Safety Review: Vaccinations and Sudden Unexpected Death in Infancy. Washington (DC): National Academies Press (US); 2003. Immunization Safety Review: Vaccinations and Sudden Unexpected Death in Infancy. Available from: https://www.ncbi.nlm.nih.gov/books/NBK221465/
• 6 – Keens et al. (1985) Ventilatory Pattern Following Diphtheria-Tetanus-Pertussis Immunization in Infants at Risk for Sudden Infant Death Syndrome. American Journal of Diseases of Children.