Researchers assert that bivalent HPV vaccination in Scotland has been “highly effective” in reducing pre-malignant cervical disease, but have failed to discuss serious adverse events following HPV vaccination or other secular trends that could provide an explanation for the declines.
Comments in response to: “Prevalence of cervical disease at age 20 after immunisation with bivalent HPV vaccine at age 12-13 in Scotland: retrospective population study.”
Comments by Exley C, Gervas J, Selley P, Stone J, Thomas N, Vasquez A, Miller NZ, in response to: Palmer T, Wallace L, Pollock KG, et al. Prevalence of cervical disease at age 20 after immunisation with bivalent HPV vaccine at age 12-13 in Scotland: retrospective population study. BMJ. 2019;365:l1161.
This collection of published comments responds to the assertion by Scottish researchers (Palmer et al., 2019) that bivalent HPV vaccination in Scotland has been “highly effective” in lowering the prevalence of pre-malignant cervical disease. The seven commenters make the following points:
- Exley critiques the authors’ “serious omission” in failing to discuss serious adverse events following HPV vaccination; those with “privileged access to human data” should use it “to cover all aspects of both efficacy AND safety of this vaccine.”
- Gervas estimates that 4,300 women would need to receive the HPV vaccine to prevent one case of severe cervical dysplasia (the “number needed to treat”).
- Selley describes secular trends in teen sexual behavior over the study period and asks whether the falling prevalence of pre-malignant cervical disease attributed to the HPV vaccine could be related to changes in sexual behavior.
- Stone calls attention to an article (Castanon and Sasieni, 2018) that reported a “dramatic increase” in England of cervical cancers in the first generation to be targeted for HPV vaccination.
- Thomas contests the lead author’s assertion that “In Scotland, as elsewhere, no serious adverse effects have been demonstrably linked to the [HPV] vaccine,” pointing to reports of several hundred thousand adverse events assembled by the World Health Organization (including 400 deaths) and almost 13,000 reported reactions in the UK, and observes that valid informed consent is not possible without communicating information about these risks.
- Vasquez points to Scotland’s public health campaign to address endemic vitamin D deficiency implemented in “close chronologic proximity” to its launch of HPV vaccination. “Crediting the reduction in HPV-related disease solely to vaccination…is potentially invalid and misleading, especially when the authors make no account whatsoever of the national program for vitamin D supplementation which started in the same timeframe.”
- Miller points out that the Palmer et al. study only included 12- and 13-year-old girls and “did not include older teens and women who are sexually active, have been exposed to HPV prior to HPV-vaccination, and are likely to have significantly worse outcomes than unvaccinated females.”