Chen Y, Li L SARS-CoV-2: virus dynamics and host response. Lancet Infect Dis. 2020 May;20(5):515-516. doi: 10.1016/S1473-3099(20)30235-8. Epub 2020 Mar 23.
Han RF, Pan JG Can intravesical bacillus Calmette-Guérin reduce recurrence in patients with superficial bladder cancer? A meta-analysis of randomized trials. Urology. 2006 Jun;67(6):1216-23.
Kleinnijenhuis J, van Crevel R, Netea MG Trained immunity: consequences for the heterologous effects of BCG vaccination. Trans R Soc Trop Med Hyg. 2015 Jan;109(1):29-35. doi: 10.1093/trstmh/tru168. Review.
Koeken VACM, Verrall AJ, Netea MG, Hill PC, van Crevel R Trained innate immunity and resistance to Mycobacterium tuberculosis infection. Clin Microbiol Infect. 2019 Dec;25(12):1468-1472. doi: 10.1016/j.cmi.2019.02.015. Epub 2019 Feb 23. Review.
Ritz N, Hanekom WA, Robins-Browne R, Britton WJ, Curtis N Influence of BCG vaccine strain on the immune response and protection against tuberculosis. FEMS Microbiol Rev. 2008 Aug;32(5):821-41. doi: 10.1111/j.1574-6976.2008.00118.x. Epub 2008 Jul 9. Review.
Spencer JC, Ganguly R, Waldman RH Nonspecific protection of mice against influenza virus infection by local or systemic immunization with Bacille Calmette-Guérin. J Infect Dis. 1977 Aug;136(2):171-5.
Wardhana, Datau EA, Sultana A, Mandang VV, Jim E The efficacy of Bacillus Calmette-Guerin vaccinations for the prevention of acute upper respiratory tract infection in the elderly. Acta Med Indones. 2011 Jul;43(3):185-90.
Prevention of Acute Respiratory Infection in Taiwanese Institutionalized Elderly (PARITIE)
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.