Mateus AL, Otete HE, Beck CR, Dolan GP, Nguyen-Van-Tam JS Effectiveness of travel restrictions in the rapid containment of human influenza: a systematic review. Bull World Health Organ. 2014 Dec 1;92(12):868-880D. doi: 10.2471/BLT.14.135590. Epub 2014 Sep 29. Review.
Schuchat A; CDC COVID-19 Response Team Public Health Response to the Initiation and Spread of Pandemic COVID-19 in the United States, February 24-April 21, 2020. MMWR Morb Mortal Wkly Rep. 2020 May 8;69(18):551-556. doi: 10.15585/mmwr.mm6918e2.
Tong JY, Wong A, Zhu D, Fastenberg JH, Tham T The Prevalence of Olfactory and Gustatory Dysfunction in COVID-19 Patients: A Systematic Review and Meta-analysis. Otolaryngol Head Neck Surg. 2020 Jul;163(1):3-11. doi: 10.1177/0194599820926473. Epub 2020 May 5.
Wójcik OP, Brownstein JS, Chunara R, Johansson MA Public health for the people: participatory infectious disease surveillance in the digital age. Emerg Themes Epidemiol. 2014 Jun 20;11:7. doi: 10.1186/1742-7622-11-7. eCollection 2014. Review.
Xiao J, Shiu EYC, Gao H, Wong JY, Fong MW, Ryu S, Cowling BJ Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings-Personal Protective and Environmental Measures. Emerg Infect Dis. 2020 May;26(5):967-975. doi: 10.3201/eid2605.190994. Epub 2020 May 17.
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.