... But it is not worth the risk of using a vaccine totally untested. ...
From
http://www.gopbriefingroom.com/index.php/topic,412701.0.html :
June 10, 2020 - Janssen Pharmaceutical accelerating its Phase I/IIa trial of its COVID-19 vaccine to the second half of July;
https://www.jnj.com/johnson-johnson-announces-acceleration-of-its-covid-19-vaccine-candidate-phase-1-2a-clinical-trial-to-begin-in-second-half-of-julyJuly 30, 2020 - Janssen Research (Johnson & Johnson) COVID-19 vaccine began Phase I/IIa clinical trial in the US and Belgium;
https://www.jnj.com/single-dose-of-johnson-johnson-covid-19-vaccine-candidate-demonstrates-robust-protection-in-pre-clinical-studiesSeptember 23, 2020 - Johnson & Johnson announced the start of its Phase III trial for its COVID-19 vaccine candidate developed by its Janssen Pharmaceutical Companies; the trial will enroll up to 60,000 volunteers across three continents;
https://www.jnj.com/johnson-johnson-initiates-pivotal-global-phase-3-clinical-trial-of-janssens-covid-19-vaccine-candidate ;
https://www.janssen.com/johnson-johnson-initiates-pivotal-global-phase-3-clinical-trial-janssens-covid-19-vaccine-candidateMarch 16, 2020 - Phase I testing begins of Moderna's experimental coronavirus vaccine; at Kaiser Permanente Washington Health Research Institute,
https://www.kpwashingtonresearch.org/news-and-events/recent-news/news-2020/kaiser-permanente-launches-coronavirus-vaccine-study-seattle ,
https://www.hhs.gov/about/news/2020/03/16/hhs-secretary-azar-statement-on-launch-of-phase-1-covid-19-vaccine-trial.html ,
https://www.nih.gov/news-events/news-releases/nih-clinical-trial-investigational-vaccine-covid-19-beginsMarch 27, 2020 - Emory University began enrolling participants for a Phase I clinical trial of Moderna's potential coronavirus vaccine;
https://news.emory.edu/stories/2020/03/coronavirus_vteu_modernastart/index.htmlMay 29, 2020 - Moderna announces first participants dosed in Phase II study of coronavirus vaccine;
https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-first-participants-each-age-cohort-dosed-phaseJune 11, 2020 - Enrollment of the younger adults group of Moderna's Phase II trial was completed;
https://investors.modernatx.com/news-releases/news-release-details/moderna-advances-late-stage-development-its-vaccine-mrna-1273July 8, 2020 - Enrollment of the older adults group of Moderna's Phase II trial was completed;
https://investors.modernatx.com/news-releases/news-release-details/moderna-completes-enrollment-phase-2-study-its-mrna-vaccineJuly 27, 2020 - Moderna announced announced that the Phase III study of its COVID-19 vaccine has begun dosing participants; the randomized, placebo-controlled trial will include some 30,000 US participants;
https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-phase-3-cove-study-mrna-vaccine-against-covidNovember 16, 2020 - Moderna announced that the independent, NIH-appointed Data Safety Monitoring Board for the Phase 3 study of its vaccine candidate against COVID-19 has informed Moderna that the trial has met the statistical criteria in the study protocol for efficacy, with a vaccine efficacy of 94.5%;
https://investors.modernatx.com/news-releases/news-release-details/modernas-covid-19-vaccine-candidate-meets-its-primary-efficacyNovember 30, 2020 - Moderna announced that the primary efficacy analysis of the Phase 3 study of its Covid-19 vaccine confirms the high efficacy of 94.1% of the first interim analysis; Moderna is submitting for an EUA with the FDA and apply for Conditional Marketing Authorization with the European Medicines Agency;
https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-primary-efficacy-analysis-phase-3-cove-studyApril 22, 2020 - Pfizer and BioNTech announced approval to begin Phase I/II trial of BioNTech’s COVID-19 vaccines in Germany;
https://www.pfizer.com/news/press-release/press-release-detail/biontech_and_pfizer_announce_regulatory_approval_from_german_authority_paul_ehrlich_institut_to_commence_first_clinical_trial_of_covid_19_vaccine_candidatesApril 29, 2020 - Pfizer and BioNTech announced that the first cohort of BioNTech’s Phase I/II clinical trial has been dosed;
https://www.pfizer.com/news/press-release/press-release-detail/biontech-and-pfizer-announce-completion-dosing-first-cohortMay 5, 2020 - Pfizer and BioNTech announced that the first participants have been dosed in the US in the Phase I/II clinical trial;
https://www.pfizer.com/news/press-release/press-release-detail/pfizer_and_biontech_dose_first_participants_in_the_u_s_as_part_of_global_covid_19_mrna_vaccine_development_programJuly 27, 2020 - Pfizer and BioNTech announced the start of a global Phase II/III clinical study of its COVID-19 vaccine, which will include up to 30,000 participants;
https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-choose-lead-mrna-vaccine-candidate-0August 12, 2020 - Pfizer and BioNTech announced that they have submitted an amended protocol to the FDA to expand the enrollment of their Phase III COVID-19 vaccine trial to up to approximately 44,000 participants, allowing for the enrollment of new populations; the company expects to reach its initial target of up to 30,000 participants next week;
https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-propose-expansion-pivotal-covid-19November 9, 2020 - Pfizer and BioNTech announced their mRNA-based SARS-CoV-2 vaccine has demonstrated evidence of efficacy against COVID-19; the first interim efficacy analysis conducted by an external, independent Data Monitoring Committee concluded that the vaccine efficacy rate was above 90% at 7 days after the second dose;
https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-vaccine-candidate-againstNovember 18, 2020 - Pfizer and BioNTech announced that, after conducting the final efficacy analysis in their ongoing Phase 3 study, their COVID-19 vaccine candidate met all of the study’s primary efficacy endpoints; analysis of the data indicates a vaccine efficacy rate of 95% (p<0.0001) in participants without prior SARS-CoV-2 infection; the companies also announced that the safety milestone required by the FDA for Emergency Use Authorization (EUA) has been achieved; Pfizer and BioNTech plan to submit a request within days for an EUA;
https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccineThe thread linked above has similar milestone dates for the AstraZeneca and Novavax vaccines (I stopped updating that thread in January), but I didn't include them because neither have submitted a request to the FDA for Emergency Use Authorization, and thus are not approved for use in the US.
The bottom line from all the milestones listed above is that the three vaccines approved for use in the US have been fully tested.