Coronavirus Research

Foundational Virology

• Zhou P, et al. "A pneumonia outbreak associated with a new coronavirus of probable bat origin." Nature, 2020. — First characterization of SARS-CoV-2 genome and bat origin.
• Andersen KG, et al. "The proximal origin of SARS-CoV-2." Nature Medicine, 2020. — Analysis of features inconsistent with deliberate engineering.
• Walls AC, et al. "Structure, Function, and Antigenicity of the SARS-CoV-2 Spike Glycoprotein." Cell, 2020. — Structural basis of ACE2 binding and vaccine design target.

Clinical Disease & Treatment

• Huang C, et al. "Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China." The Lancet, 2020. — First major clinical description of COVID-19 disease.
• Beigel JH, et al. "Remdesivir for the Treatment of Covid-19." NEJM, 2020. — Pivotal ACTT-1 trial establishing remdesivir benefit in hospitalized patients.
• RECOVERY Collaborative Group. "Dexamethasone in Hospitalized Patients with Covid-19." NEJM, 2021. — Landmark finding: dexamethasone reduced 28-day mortality in patients requiring oxygen.

Vaccines

• Polack FP, et al. "Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine." NEJM, 2020. — Phase 3 trial: 95% efficacy, 43,448 participants.
• Baden LR, et al. "Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine." NEJM, 2021. — Moderna Phase 3 trial: 94.1% efficacy.

Epidemiology & Public Health

• Worobey M, et al. "The Huanan Seafood Wholesale Market in Wuhan was the early epicenter of the COVID-19 pandemic." Science, 2022.
• Wang H, et al. "Estimating excess mortality due to the COVID-19 pandemic." The Lancet, 2022. — Excess mortality estimated at 18.2 million through December 2021.

Long COVID

• Thaweethai T, et al. "Development of a Definition of Postacute Sequelae of SARS-CoV-2 Infection." JAMA, 2023. — NIH RECOVER Initiative defining Long COVID symptom clusters.
• Lopez-Leon S, et al. "More than 50 long-term effects of COVID-19: a systematic review and meta-analysis." Scientific Reports, 2021.

Reading a COVID-19 Paper: What to Check First

The landmark studies above are cited across this site, and a reader who wants to check any of them rather than take our word for it can do so from the DOIs. Four things decide how much weight a COVID-19 finding carries, and they apply to every paper in this list.

• Which variant era, and which immunity background. The vaccine and antiviral trials below enrolled unvaccinated, previously uninfected people in 2020–2021, against the ancestral strain or Alpha. Their absolute effect sizes do not transfer to a 2026 population with layered immunity from vaccination and repeated infection. This single point explains most apparent contradictions between older trials and newer observational data.
• Absolute versus relative effect. "89% relative risk reduction" and "6.32 percentage points" describe the same EPIC-HR result. The relative figure travels well in headlines; the absolute figure is what a patient experiences, and it shrinks as baseline risk falls.
• The confidence interval, not just the point estimate. MOVe-OUT's full-population result for molnupiravir was a 3.0-percentage-point benefit with a 95% interval running to −0.1 — a tenth of a point from zero. A paper reporting an interval that nearly touches the null is telling you something a point estimate hides.
• Randomised or observational. Randomisation is what allows a causal claim. Observational studies of who was infected, vaccinated or reinfected compare people who differ in ways that also affect outcomes; adjustment reduces that problem without removing it.

Two things this literature does not contain. There is no head-to-head randomised trial comparing the COVID-19 vaccines with each other, and none comparing the outpatient antivirals with each other — which is why "Novavax vs Pfizer" and "remdesivir vs Paxlovid" have no trial answer, only a logistical one. And there is no efficacy trial of any annual reformulation: since the original authorisations, updated vaccines have been cleared on immunogenicity, the same regulatory pathway used for influenza vaccines. Our vaccines and treatment pages set out each trial with its numbers.

Where the Live Data Lives — and What Stopped

Peer-reviewed literature answers questions about mechanism and effect. Questions about what is happening right now are answered by surveillance datasets, and the honest summary in 2026 is that several of them have stopped.

• Still publishing: CDC's SARS-CoV-2 variant proportions (four-week periods, roughly monthly); the National Syndromic Surveillance Program's emergency-department percentages (weekly); the wastewater viral activity network (weekly); and COVID-NET hospitalisation rates (weekly, by season).
• Stopped: CDC's model-based variant Nowcast, last published April 10, 2026. The CDC/NCHS Household Pulse Survey's Long COVID module, whose final round closed September 16, 2024. National case notification, since COVID-19 ceased to be nationally notifiable. WHO's clean annual global case and death counts, as global surveillance wound down.
• Thinning: national variant estimates now rest on so few sequences that in the most recent published period all 18 lineage estimates carry CDC's own low-precision flag — against 21 of 43 two years earlier.

Our variants, symptoms and Long COVID pages each report the relevant series with the date of the data they were read from, and the homepage carries the current weekly readings together.

Key Ongoing Data Sources

• CDC COVID-19 Data Tracker — U.S. case, hospitalization, and vaccination surveillance
• WHO COVID-19 Dashboard — Global epidemiological data
• ECDC COVID-19 — European surveillance data and situation updates from the EU public-health agency
• NIH LitCovid — Curated literature hub for COVID-19 biomedical research
• medRxiv COVID-19 Preprints — Preprint server for health sciences. Preprints are not peer reviewed; this site does not cite one as established evidence.
• CDC SARS-CoV-2 Variant Proportions — the underlying national and regional estimates, with confidence intervals and reliability flags
• CDC RESP-NET (COVID-NET) — laboratory-confirmed hospitalisation rates per 100,000, by season and age group
• CDC NSSP emergency-department visits — weekly percentage of ED visits diagnosed as COVID-19, flu or RSV
• CDC National Wastewater Surveillance System — weekly wastewater viral activity levels, national, regional and by site
• ClinicalTrials.gov — registered trial records; the source of record for whether a treatment or vaccine candidate is actually in a trial, and at what phase