🚨Fake News Alert🚨 Viral Posts Misuse Rat Study to Make Unfounded Claims About COVID-19 Vaccines and Autism

Multiple scientists expressed concerns to us about the high COVID-19 vaccine dose given to the pregnant rats.

Staci Bilbo, a neuroimmunologist at Duke University who studies how the immune system influences brain development, told us that vaccine doses are “extremely carefully” adjusted during vaccine development. Researchers determine the smallest dose that will generate the needed immune response.

Giving the rats — which on average weighed less than 8 ounces — a full adult human COVID-19 vaccine dose was equivalent to giving an average-weight American woman around 350 times the recommended dose of the Pfizer/BioNTech vaccine, according to Bilbo’s calculation. 

“If you give a high enough dose of anything it’s going to probably have impacts,” she said.

In response to questions about the dose, Erdogan told Health Feedback that “there’s no established standard for mRNA vaccine dosages in rats due to the lack of specific dose studies” and that relatively high doses have been used for studies of other animals of varying sizes.

Jeffrey S. Morris, director of the division of biostatistics at the University of Pennsylvania’s Perelman School of Medicine, also told FactCheck.org that the high dose given to the rats was a limitation of the study. “This does not make the results irrelevant, since super high dose can potentially detect some potential issue that might manifest in some humans, but if I were reviewing this article I would make the authors emphasize the multiple of how much larger the effective dose in the animal study is to the current human dose, and include the qualifier that this is one reason why it is not clear whether these results are relevant to what is experienced by humans given the current doses.”

Christopher Coe, a psychoneuroimmunologist and professor emeritus at the University of Wisconsin-Madison, told us via email that were it his study, he would also have wanted to give the rats a low dose of the vaccine to see if results varied by dose. Coe has done studies on the effects of infection and maternal inflammation on the fetus during pregnancy.

Coe said it was important to take reports of drug or vaccine adverse events seriously, but he also listed numerous other concerns about the paper.

For example, he said the researchers did not provide information about the rats and their pregnancies that could have shed light on how the injections affected them — and whether or not this was likely to be relevant to humans. This missing information included, for instance, whether the rats had an inflammatory reaction to the injections — the hypothesized pathway for how vaccination during pregnancy might affect neurodevelopment.

Teresa Reyes, a professor of pharmacology and systems physiology at the University of Cincinnati College of Medicine, told us via email that information was missing on the length of the rat pregnancies. “If the pregnancy length was significantly different, it could indicate that the litters were born prematurely, which confounds the interpretation of the findings,” she said.

In humans, COVID-19 vaccination during pregnancy has not been shown to increase preterm birth and may even protect against it.

She also said that information was missing on the weights of the pregnant rats, or dams, over time and their pups. “Significant differences in weight (e.g., vaccine exposed dams lost weight during the study) could indicate that the dams were severely ill in response to the vaccine, again confounding the interpretation of the study,” she said.

Coe said that he would have wanted “to replicate the findings rather than rush to publish on the basis of one experiment,” suggesting that both the authors of the paper and outside researchers should try to replicate the results.

And he expressed concern about the study’s statements that altered rat behaviors were “autism-like,” given that autism spectrum disorder is a “complex neurodevelopmental disorder.” 

Brian Lee, an associate professor of epidemiology and biostatistics at the Drexel University Dornsife School of Public Health who studies prenatal exposures and autism risk, told us via email that it is hard to diagnose autism in humans, let alone in rats. “It’s hard to read into some behavioral tests for a rat and imagine it translates 100% to an autism diagnosis in humans,” he said.

There also appeared to be issues with the study’s experimental design and statistical analysis.

For instance, studies of prenatal exposures need to account for something called “litter effects” — or the fact that the multiple offspring born in the same litter to the same animal mother might share characteristics.

“The authors did not describe any approach to address the potential for a litter confound which could skew the findings (e.g., one dam has a significantly different response, multiple pups are used from that litter, and this skews the findings),” Reyes said. 

Additionally, the authors wrote that they set out to determine whether maternal vaccination led to “any sex-specific neurobehavioral changes” — or ways in which sex and vaccination, in combination, affected the rats’ behavior.

The authors didn’t find evidence of such sex-specific effects on social behavior, but they nevertheless went on to compare social behavioral results from the male pups of vaccinated mothers versus unvaccinated mothers and highlighted the results — something Reyes said they shouldn’t have done. “By improperly using statistics to analyze the data, the conclusions are not valid,” she said. “It is impossible to verify the stated claims because statistics were used incorrectly.”