The National Institute of Health created an article on Understanding Clinical Studies in 2016 and included a useful infographic. More detail about clinical research that is not covered in this blog post can be found on Medlineplus.gov.
Observational studies are unable to prove cause and effect, but are useful for finding associations and sparking hypotheses, especially in instances of genetic, environmental, behavioral, and infections causes of disease.
There are five types of observational studies listed below in ascending level of scientific strength:
A well-designed clinical trial is usually necessary to establish cause and effect and can be used when trying to scientifically validate a way to prevent, detect, or treat a disease. The current topic in the news is the COVID-19 pandemic. Understanding clinical trials can help explain why it was anticipated it would take many months and likely more than a year (if possible) to bring a safe and effective vaccine to the public. A strategy to speed up the eventual availability of a COVID-19 vaccine has been to mass produce multiple potential vaccines before the conclusion of clinical trials. This potentially allows immediate market available of successful vaccine(s), while mass produced unsuccessful vaccine candidates will be destroyed.
Clinical Trials involve four phases summarized below.
More information about Clinical Trials and how to enroll a patient can be found on the NIH website.