… Around 2006, CDC took stock of the persistently low compliance with its influenza recommendations, largely ignored by both doctors and pregnant women, and began more aggressively promoting flu shots for pregnant women. In an update in the Morbidity and Mortality Weekly Report, CDC cited as evidence of the vaccines’ safety during pregnancy a grand total of two retrospective epidemiological studies of medical records—one of which was published in 1973.
In 2011, CDC and other medical trade organizations also began recommending that all pregnant women get the Tdap vaccine (tetanus-diphtheria-acellular pertussis), which, among other ingredients, contains neurotoxic aluminum. Tdap coverage in pregnancy increased substantially following this recommendation, particularly in women who also received other vaccines during pregnancy. The FDA’s original approval of the two Tdap brands (Boostrix and Adacel) in the mid-2000s was as a booster for teens and adults, and the product inserts state that Tdap should be given during pregnancy only “when benefit outweighs risk.” At the time of the 2011 recommendation, no prelicensure studies of Tdap safety during pregnancy were available, so most of the (largely unpublished) data used to justify the recommendation came from post-licensure pregnancy pharmacovigilance conducted by vaccine manufacturers. To this day, online information for Boostrix states that “it is not known whether Tdap vaccine will harm an unborn baby.”
How have these vaccine recommendations worked out for pregnant women and their babies? Published reports point to an increased risk of miscarriages and elevated risks of birth defects and autism in the offspring of mothers who received influenza vaccines during pregnancy—described by World Mercury Project on multiple occasions. Although evidence about Tdap is still emerging, the global VigiBase database (launched in 1978 to collect reports of vaccine-related adverse events from heterogeneous systems in 110 countries) indicates that three-fifths (58%) of all the Tdap-related adverse events reported to VigiBase have occurred since 2010, half (49%) have been in females and 7% have been in the 18-44-year age group. Admittedly, the non-systematic nature of the VigiBase data makes it difficult to interpret these trends, but it still seems surprising that the default official position shared by academics and regulators is that “there is no documented causal evidence of developmental or reproductive toxic effects in humans following the use of [any] approved vaccine.”…
Prevailing notions of what is “ethically permissible or necessary” with regard to the medical protection of pregnant women appear to be somewhat malleable. There was, in fact, a time when regulators did not display the same levels of insouciance about vaccine and drug administration during pregnancy. Formerly, federal policy (at least on paper) deemed it prudent to exclude women of childbearing age and pregnant women from taking part in clinical trials to test new drugs. This precautionary stance—grounded in established toxicological principles—aimed to forestall developmental toxicity disasters such as the one that occurred with thalidomide. In 1993, however, mounting pressure from various sectors persuaded the Food and Drug Administration (FDA) to abolish the perceived “medical research gender gap.” The FDA’s Center for Drug Evaluation and Research (CDER) reversed course and began encouraging routine inclusion of reproductive-age women in clinical trials—but it continued to note the special circumstances of pregnant women (and is just now getting around to formalizing scientific and ethical guidance pertaining to pregnant women’s participation in drug trials).
Over at the FDA’s sister office CBER (Center for Biologics Evaluation and Research), which oversees vaccines and other “biologics,” officials initially seemed to share CDER’s apparent restraint concerning pregnant women. In 1996, CBER’s Office of Vaccines Research and Review (OVRR) wrote up a detailed two-page memorandum on reproductive toxicity and vaccines. It then invited the public to submit written comments (in 2000) and eventually published “Guidance for Industry: Considerations for Developmental Toxicity Studies for Preventive and Therapeutic Vaccines for Infectious Disease Indications” (in 2006).
The memo and subsequent guidance spelled out the critical need to conduct preclinical studies in animal models to assess reproductive and developmental toxicity “prior to licensure of vaccines intended for maternal immunization and/or women of childbearing age” (see table below). However, the documents admitted that “lack of adverse effects on embryo/fetal development in an animal study does not necessarily imply absence of risk for humans.” Moreover, given the FDA’s emphasis (in a header on every page) that all of the recommendations included in its guidance are non-binding, the extent to which vaccine manufacturers choose to abide by them is largely unknown.
In 2013, when the World Health Organization’s (WHO’s) Global Advisory Committee on Vaccine Safety reviewed the safety of the growing number of vaccines intended for pregnant women, it noted “the limited amount of clinical trial data on pregnant women” and, like the FDA, emphasized the importance of “enhanced pharmacovigilance in the post-licensure phase.” However, neither the FDA nor the WHO commented on the possible conflicts-of-interest inherent in having vaccine manufacturers conduct their own pharmacovigilance….