See the research and articles on the issue of healthy user bias in research:
Healthy User and Related Biases in Observational Studies of Preventive Interventions: A Primer for Physicians https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077477/ & https://vaccinepapers.org/wp-content/uploads/Healthy-User-and-Related-Biases-in-Observational-Studies-of-Preventive-Interventions.pdf
Bias in clinical research https://www.sciencedirect.com/science/article/pii/S008525381552958X
Healthy User Bias: The Fatal Flaw in Vaccine Safety Research https://vaccinepapers.org/healthy-user-bias-why-most-vaccine-safety-studies-are-wrong/
The Healthy User Effect: Ubiquitous and Uncontrollable https://www.jhsph.edu/research/centers-and-institutes/center-for-drug-safety-and-effectiveness/training/seminar-series/Sumit_Majumdar.pdf
Influence of healthy candidate bias in assessing clinical effectiveness for implantable cardioverter-defibrillators: cohort study of older patients with heart failure https://www.bmj.com/content/348/bmj.g2866
Industry Funding of Clinical Trials: Benefit or Bias? https://jamanetwork.com/journals/jama/fullarticle/196846
