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Have regulators historically allowed enough time for Phase 3 trials to show that a vaccine does not cause congenital defects? Are they making an exception for Covid vaccines?

Because the Pfizer/Biontech vaccine for coronavirus is now available for all over-16s in Israel (see https://www.ft.com/content/0cdc8563-1e6d-4089-bedb-b0f675c0d683 ), but I wonder whether it would not have been better to wait a few months to give Phase 3 trials a chance to yield data on congenital defects after some participants give birth. (Phase 3 trials started on July 27 according to https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccine ). What do we know about the Pfizer/Biontech vaccine which would make researchers confident that it doesn't cause congenital defects? What data do we have to show it does or doesn't? When did/would we get this data? Did the Israeli regulator decide to take a risk in the absence of data?

I am also interested in these questions applied to the Oxford/AstraZenica vaccine, Moderna vaccine, and other regulators/vaccine approval processes for coronavirus vaccines.

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    Why would the vaccine cause birth defects? – Bryan Krause Feb 6 at 19:45
  • Thre largest man-made medical disaster ever consisted of congenital defects as a side-effect of a medication approved by complacent regulators (ie the Thalidomide scandal). So surely it would now be a regulator's duty of care to ensure there is no risk of it happening again. Is there some underlying principle which allows regulators to approve without giving which time to collect data on congenital defects? For example, are congenital defects unlikely to be a major risk in the particular families of vaccines which Oxford-Astrazeneca/Pfizer-Biontech/Moderna vaccines belong to? – novice Feb 6 at 20:24
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    Thalidomide is a small molecule drug, not a vaccine. – Bryan Krause Feb 6 at 20:30
  • "How does thalidomide cause the severe and wide range of damage in the embryo? The short answer is that it is still not fully understood." according to ncbi.nlm.nih.gov/pmc/articles/PMC4737249 So it would not be enough to say that "Vaccine X will not cause congenital defects because it is different to Thalidomide on a molecular level". Could you instead compare the pharmacology of a Covid vaccine with the pharmacology of a family of vaccines which are for some specific reason considered unlikely to cause birth defects – novice Feb 6 at 20:44
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    Have you done any research into the current Covid vaccines and how they relate to others? Your comments suggest you have not. – Bryan Krause Feb 6 at 20:46
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I don't think there can be data on this, given how short the trials were. On the other hand, I don't think that scientists fear birth defects from COVID-19 vaccines (These vaccines' intended mechanism does not involve modifying your DNA, mind you)

The only known mechanism I could find where a vaccine would cause birth defects was when the virus itself was causing birth defects, and the vaccine, rather than being useful, was enhancing the virus. (This is called antibody-dependent enhancement, and the virus in question was Zika, studied in mice)

That is not to say that birth defects from COVID-19 vaccination are known to be completely impossible. But one must weigh the rather theoretical (and likely non-existent) risk of COVID-19 vaccines causing birth defects vs the very real risk of dying from COVID-19.

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