Intended for healthcare professionals

Rapid response to:


US county bars unvaccinated children from public spaces amid measles emergency

BMJ 2019; 364 doi: (Published 28 March 2019) Cite this as: BMJ 2019;364:l1481

Linked opinion

Measles in America—what’s playing out in New York State is nightmarish

Rapid Response:

Re: US county bars unvaccinated children from public spaces amid measles emergency

Response 3 to Allan S. Cunningham

As I wrote in Response 2, it would take a paper with hundreds of references to show that the weight of evidence supports both the seriousness of flu and the value of the flu vaccine. However, as one more example of cherry-picking confirmation bias, he writes: “Right now I am waiting for the BMJ to publicize the latest piece of bad news about influenza vaccines: an overall doubling of miscarriage risk among women who get flu shots early in pregnancy, and an 8-fold increase in risk after getting the second of two pH1N1-containing vaccines in consecutive seasons. (Donahue, Vaccine 2017;35:5314) The more we hear about them the more we realize that, like the fabled emperor, the flu vaccines have no clothes.”

The authors of the study admit to several weaknesses, among them: “it is possible that women with certain comorbidities or other risk factors for SAB were preferentially vaccinated. . . vaccination status may have been misclassified if women received a vaccine that was both outside of their health care system and not reported to their provider . . . It is important to note that this study does not and cannot confirm a causal association.”(Donahue, 2017)

In a subsequent exchange of letters, the authors, while defending their methodology, write: “Influenza infection poses a serious risk to pregnant women and their children, and we support current ACIP recommendations for vaccination during pregnancy. We understand these study results may be concerning for pregnant women and expect a follow-up study will be completed by early 2019. Until then, patients should be educated regarding vaccine recommendations, findings and uncertainties of this study, and the overall strong safety profile of influenza vaccination during pregnancy.” (Donahue, 2018)

In a review of flu vaccine and pregnancy, Giles et al. include several similar studies that found NO risk and their overall conclusion was: “there is no evidence of an increased risk of adverse pregnancy outcomes following influenza vaccination in pregnancy. Despite this reassuring finding, there remain some important areas where more data from ongoing surveillance and formal research projects for pregnancy-related safety of vaccination would be beneficial.” (Giles, 2019)

And Dr. Paul Offit writes: “The CDCʼs observation was inconsistent. Researchers had studied two influenza-vaccine seasons: 2010-2011 and 2011-2012. The problem of first trimester spontaneous abortions occurred during the first season but not the second. . . Six previous studies had failed to find any evidence that an influenza vaccine given during the first trimester had increased the risk of spontaneous abortions. In other words, the CDC study was an outlier.” (Offit, 2017)

Notice that the Donahue study authors included Frank DeStefano, who has authored numerous articles supporting vaccines. So, it shows that even the staunchest supporters of vaccines do so in an objective manner, not biased as Cunningham would like to believe ! ! !

And the Donahue follow-up study has now been completed and guess what? No association was found. Their conclusion: “No significant association between influenza vaccine receipt and SAB, regardless of prior season vaccination status. Odds ratios were less than or close to 1.0 in all risk windows.” (Donahue, 2019) So, Cunningham seems to have leapt at the chance to attack a vaccine based on one study, a study that itself explicitly stated it could not determine a causal association and listed a number of caveats. Cunningham did not discuss studies that found no association. And Cunningham didn’t wait until the second Donahue study was carried out.

So much for Cunningham’s: “The more we hear about them the more we realize that, like the fabled emperor, the flu vaccines have no clothes.” Cunningham’s antivaccine bias is quite clear. For him, the estimated 36,400 - 61,200 deaths attributed to flu, the estimated 531,000 - 647,000 hospitalizations, plus estimated 37.4 million - 42.9 million flu illness, representing a week or more of suffering, mean little, and for every study he can cite, there are literally dozens that show the value of the flu vaccine (CDC, 2019ab). Plus, overwhelming evidence find the flu a significant risk for both the pregnant woman and the fetus (CDC, 2019c). Note that the CDC website gives references to the above. In addition, the estimates, for instance, of deaths, are because if someone dies of pneumonia or heart disease, hospitals don’t always do labs for flu if symptoms have subsided. For instance, flu damages the epithelials of the lungs allowing for pneumonia-causing bacteria to attack. Estimates overall are based on lab confirmations of flu, thus flu season, and comparisons of instances of pneumonia and heart disease when weak flu season, serious flu season, and off-flu season. The methodology is quite involved, which is why ranges are given.

One last thought. Statistical significance doesn’t mean importance, it means that despite the best efforts to equalize groups on all variables except the one of interest, random chance means that the results of a study could be the result of some unmeasured variable(s), not the variable being studied. So, a p = 0.05 means that one would expect the result to occur 5% of the time from uncontrolled variables, which is why various replications are the sine qua non of science, not cherry-picking the studies that confirm one's bias ! ! !


CDC (2019a Feb 12). Pregnant Women & Influenza (Flu). Available at:

CDC (2019b Feb 26). Flu Symptoms & Complications. Available at:

CDC (2019c May 10). Influenza. Available at:

Chambers CD, Johnson DL, Xu R et al. (2016). Safety of the 2010–11, 2011–12, 2012–13, and 2013–14 seasonal influenza vaccines in pregnancy: Birth defects, spontaneous abortion, preterm delivery, and small for gestational age infants, a study from the cohort arm of VAMPSS. Vaccine; 34: 4443-4449. Available at:

Cunningham AS (2017 Sep 22). Vaccine authorities don't want to know about adverse effects. II. BMJ Rapid Responses. Available at:

Donahue JG, Kieke BA, King JP, DeStefano et al. (2017 Sep 25). Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010–11 and 2011–12. Vaccine; 35 (40): 5314-5322. Available at:

Donahue JG, Kieke BA, King JP et al. (2018 Apr 19). Response to three Letters to the Editor regarding: Donahue JG, et al. ‘‘Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010–11 and 2011–12”. Vaccine 35 (2017) 53-14–5322. Vaccine; 36(17): 2231-2232.

Donahue J (2019 Feb 27). Case-Control Study of Inactivated Influenza Vaccine and Spontaneous Abortion in the Vaccine Safety Datalink, 2012-13, 2013-14, and 2014-15. Slide Show Presentation to Advisory Committee on Immunization Practice. Available at:

Eaton A, Lewis N, Fireman B et al. (2018). Birth outcomes following immunization of pregnant women with pandemic H1N1 influenza vaccine 2009–2010. Vaccine; 36: 2733-2739. ABSTRACT Available at: [Note I have the paper]

Fell DB, Platt RW, Lanes A et al. (2015 Jan). Fetal death and preterm birth associated with maternal influenza vaccination: systematic review. BJOG : an international journal of obstetrics and gynaecology; 122(1): 17-26. Available at:

Giles ML, Krishnaswamy S, Macartney K, Cheng A (2019). The safety of inactivated influenza vaccines in pregnancy for birth outcomes: a systematic review. Human Vaccines & Immunotherapeutics; 15(3): 687-699. Available at:

Håberg SI, Trogstad L, Gunnes N et al. (2013 Jan 24). Risk of fetal death after pandemic influenza infection or vaccination during pregnancy. New England Journal of Medicine; 368(4): 333-340. Available at:

Louik C, Ahrens K, Kerr S et al. (2013). Risks and safety of pandemic H1N1 influenza vaccine in pregnancy: Exposure prevalence, preterm delivery, and specific birth defects. Vaccine; 31: 5033-5040. Available at:

Offit PA (2017 Sep 24). The Pregnancy Vaccine Scare That Should Have Never Been: Why that CDC study on flu shots during the first trimester should never have been published. The Daily Beast. Available at:

Omer SB (2017). Maternal Immunization. New England Journal of Medicine; 376: 1256-67.

Competing interests: No competing interests

15 May 2019
Joel A Harrison
Long-Retired Epidemiologist
I have NEVER worked for the FDA, NIH, CDC, any pharmaceutical company, nor ever purchased pharmaceutical stocks