Thread by @llborio

Thread: 1. Recent statements by @SteveFDA that @US_FDA may authorize #COVID19 vaccines before completing clinical trials are generating much anxiety and setting up a twitter storm. @Pfizer frequent messaging that it will have results on its vaccine soon isn’t helping.

2. Some prominent scientists & public health experts have called for full @US_FDA licensure before #COVID19 vaccines are distributed. I disagree with that.

3. @US_FDA standards for licensure are extremely stringent, as they should be, and they should not loosen them just because we are in a pandemic.

4. If a vaccine is shown to be safe & effective in adequate & well-controlled Phase 3 trials, withholding it until all of the stringent licensure requirements are met isn't the answer either. Some of requirements for @US_FDA licensure require data that can't be generated quickly.

5. Safe & effective vaccines can save lives and help contain the pandemic. The #EUA is the most appropriate regulatory mechanism for distributing vaccines that have been shown to be safe & effective in phase 3 #RCTs but have not yet met all of the @US_FDA standards for licensure.

6. But the #EUA should not be issued before clear demonstration of safety and efficacy in #RCTs. Each vaccine #RCT is designed to enroll about 30,000 people. This number is necessary to identify a moderately effective vaccine.

7. However, if a vaccine is extraordinarily effective – let’s say, more than 90% effective - it is possible that we would find out before all 30,000 people are enrolled in the trial. The independent DSMB will assess data at prespecified intervals.

8. The DSMB will recommend whether the trial should cont. or stop (for example, if there are safety signals or a vaccine is shown to be effective). Btw, the DSMB can’t make up the rules as they go. It's all prespecified in the protocol.

9.If the trial is stopped early, before full enrollment, b/c a vaccine is shown to be highly safe & effective, let’s celebrate an important milestone. The @US_FDA will review the data carefully and, hopefully, consult its advisory committee before taking regulatory action (#EUA).

10. Lastly, before any dose is distributed, these must be in place: a strong pharmacovigilance program to monitor for safety signals; a plan to collect additional data (e.g., duration of immunity)...

11. ...clarity as to who should receive vaccine first (some vaccines may not be appropriate for everyone); clear, consistent and truthful communications; and a competent system to manage one of the most complex vaccine distribution programs in public health history.