Our Sources
The primary authorities behind the health information on the Virus Questions network.
Centers for Disease Control and Prevention (CDC)
The CDC is the primary U.S. public health authority. We use CDC guidance for clinical descriptions of disease, transmission routes, treatment and prevention recommendations, outbreak surveillance, and travel advisories. The CDC is the first source we consult for any U.S.-relevant health claim.
World Health Organization (WHO)
The WHO is the international public health authority. We use WHO guidance for global outbreak status, Public Health Emergency of International Concern (PHEIC) declarations, global epidemiological data, and international travel guidance. For any outbreak with international scope, WHO situation reports are a primary reference.
U.S. Food and Drug Administration (FDA)
The FDA is the U.S. authority for vaccine approvals, treatment authorizations (including Emergency Use Authorizations), and drug safety. We use FDA sources for any claim about approved or authorized vaccines and treatments.
National Institutes of Health (NIH) / NIAID
NIH and its National Institute of Allergy and Infectious Diseases (NIAID) publish foundational research and clinical guidance on infectious diseases. We use NIH sources for research summaries, mechanism-of-disease explanations, and clinical trial data.
European Centre for Disease Prevention and Control (ECDC)
The ECDC provides European epidemiological surveillance and guidance. We use ECDC sources where European-specific data, outbreak tracking, or guidance is relevant — particularly for hantavirus (where European strains differ significantly from U.S. strains) and for internationally circulating diseases.
Peer-reviewed journals
For mechanistic explanations, clinical data, and emerging research not yet reflected in authority guidance, we cite peer-reviewed literature. Primary journals used:
- The New England Journal of Medicine (NEJM)
- The Lancet
- Nature Microbiology
- Morbidity and Mortality Weekly Report (MMWR, CDC)
- PubMed-indexed studies in infectious disease, virology, and epidemiology
All cited studies are linked directly to PubMed or the journal's stable URL. We note when a study has been retracted or significantly disputed.
National health ministries
For outbreak-specific data — case counts, geographic extent, outbreak declarations — from affected countries, we cite the relevant national health ministry (e.g., DRC Ministry of Health for the 2026 Ebola outbreak). These are used as primary data sources, not as authoritative clinical guidance.
What we do not use as sources
- News articles (we link to news from CoronavirusQuestions.com and EbolaQuestions.com, but do not source health claims from news)
- Other health websites, including well-known aggregators like WebMD or Healthline
- Preprints not yet peer-reviewed (cited only as "preliminary findings" when directly relevant)
- Social media posts or expert opinions not published in peer-reviewed form