marker_id,date,event,detail,total_doses_at_date_approx,source
V1,2020-12-11,Pfizer-BioNTech EUA granted,"FDA granted Emergency Use Authorization for Pfizer-BioNTech (BNT162b2) COVID-19 vaccine for persons 16 and older.",0,https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/pfizer-biontech-covid-19-vaccines
V1b,2020-12-14,First vaccinations administered,"First COVID-19 vaccinations administered in the United States to healthcare workers and long-term care residents.",<1M,https://www.cdc.gov/covid-data-tracker
V2,2020-12-18,Moderna EUA granted,"FDA granted Emergency Use Authorization for Moderna (mRNA-1273) COVID-19 vaccine.",<1M,https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/moderna-covid-19-vaccines
V3,2021-02-01,Phase 1b/1c expansion begins,"Rollout expands to adults 65+, frontline essential workers, and other Phase 1b/1c populations per CDC ACIP guidance.",~30M,https://www.cdc.gov/vaccines/covid-19/phased-implementation.html
V4,2021-02-27,Johnson & Johnson (Janssen) EUA granted,"FDA granted EUA for J&J single-dose adenovirus vector vaccine. Added a third authorized vaccine to the U.S. rollout.",~70M,https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/janssen-covid-19-vaccine
V5,2021-04-19,All adults 18+ eligible nationwide,"All U.S. states opened COVID-19 vaccine eligibility to all adults 18 and older.",~130M,https://www.cdc.gov/covid-data-tracker
V6,2021-08-23,Pfizer-BioNTech full FDA approval,"FDA granted full (non-emergency) approval for Pfizer-BioNTech vaccine under the name Comirnaty for persons 16+. First fully approved COVID-19 vaccine in the U.S.",~360M,https://www.fda.gov/vaccines-blood-biologics/vaccines/comirnaty
V7,2021-11-01,Booster recommendation expanded to all adults 18+,"CDC recommended COVID-19 booster doses for all adults 18 and older, following earlier rollout to 65+ and high-risk populations.",~415M,https://www.cdc.gov/mmwr/volumes/70/wr/mm7044e2.htm
V8,2022-09-01,Bivalent boosters authorized,"FDA authorized updated bivalent mRNA boosters targeting both original strain and Omicron BA.4/BA.5 subvariants. CDC recommended them as the standard booster.",~615M,https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/bivalent-boosters-targeting-omicron