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Health outcomes of young children born to mothers who received 2009 pandemic H1N1 influenza vaccination during pregnancy: retrospective cohort study

BMJ 2019; 366 doi: (Published 10 July 2019) Cite this as: BMJ 2019;366:l4151

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Flu vaccination in pregnancy

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Influenza vaccination, autism, AFM, etc.....

It is taboo to suggest that Influenza vaccines are ineffective or could be harmful. Suggesting a link to autism adds insult to injury. Possibly this is why Walsh and her colleagues did not acknowledge data indicating a 20% increase in the risk of autism spectrum disorder/ASD among the offspring of women who received flu shots during the first trimester of pregnancy. (BMJ 2019;366:l4151) I write to reinforce the comments of Doshi, Jefferson, Stone and Stephen regarding the Walsh article. (BMJ rr Aug 2-5, 2019)

Autism is associated with increased levels of maternal cytokines during gestation (Jones, Mol Psychiatry 2017;22:273), and influenza vaccines induce proinflammatory cytokine responses during pregnancy (Christian, Am J Reproduc Immunol 2013;70:45). Therefore, a causal link between flu shots in pregnancy and ASD is biologically plausible. We assume that inflammation from infection is more dangerous to the fetus than inflammation from vaccination. However, inflammation exposure from vaccination is far more frequent than exposure from infection. In the Zerbo California cohort there were 196,929 pregnant women. In the first trimester only 443 women had influenza infections while 13,477 received flu shots. (Table 3, JAMA Pediatr 2017;171( 1):e163609)

Maternal vaccines have been called “the next frontier in vaccinology.” (Omer, NEJM 2017;376:1256) Where flu shots are concerned some of us think it is a frontier that should never have been crossed, partly because of the autism link, and are calling for unbiased and well-controlled trials before adhering to routine recommendation in developed nations. It is just one example of the vexed situation of influenza vaccines. There are others.

In the US we are now entering our acute flaccid myelitis/AFM season. As of August 2 there have been 574 confirmed AFM cases in the US since August 2014. (CDC, AFM Investigation) AFM predominates in schoolchildren and coincides with the annual campaign for seasonal influenza vaccination and back-to-school shots. AFM is probably caused by non-polio enteroviruses. However, we know that a substantial proportion of poliomyelitis is provoked by injections as co-factors (Mawdsley, Lancet 2014;384:300), and the possibility has been suggested that the same is also true of AFM. (Gromeier, J Virology 1998;72:5056. Cunningham, BMJ rr 2015-2019) US public health authorities are aware of this but so far have not publicly acknowledged or investigated the possibility.

There are too many ways to obscure serious vaccine safety issues from the general public and even from health professionals.


Competing interests: No competing interests

07 August 2019
Allan S. Cunningham
Retired pediatrician
Cooperstown NY 13326 USA <