Will Vaxcyte announce that the VAX-31 phase 3 OPUS-1 trial met its non-inferiority criteria before 31 January 2027?
deadline 2027-01-31
confidence medium
tier 4 evidence
Resolved
YES — 2026-10-05
Communiqué officiel Vaxcyte : « Vaxcyte Reports Positive Topline Data from OPUS-1 » — 2026-10-05 ·
source
66%Asturna estimate
Resolution criterion
Yes if Vaxcyte publishes a topline results release explicitly stating that OPUS-1 met its immunogenicity non-inferiority criteria, by 31 January 2027. A delay, a failure, or a partial hit count as no.
Verified starting state
OPUS-1 enrolment complete (roughly 4,000 adults, compared against PCV21 and PCV20), topline results expected in the fourth quarter of 2026. A 31-valent vaccine must demonstrate non-inferiority across many serotypes simultaneously; partial failures on a few serotypes are common in this class. (23 March 2026)
What pushes it up
- Vaxcyte has narrowed the guidance for topline data to late October 2026, which is well before the January 2027 deadline [4].
- The company recently released preliminary safety, tolerability, and immunogenicity data, suggesting the trial is progressing as planned [4].
- Vaxcyte has a track record of successful high-valency vaccines (VAX-20), which increases the prior probability of success for VAX-31 [1].
What pushes it down
- All provided press articles are Tier 4 (aggregators/pickups) and lack direct Tier 1 or 2 confirmation of the specific non-inferiority outcome, only confirming the timeline [4].
- The starting state notes that partial failures on a few serotypes are common in this class, which would count as a 'no' under the resolution criteria [1].
What would move this number most
Whether the immunogenicity data for all 31 serotypes meets the non-inferiority margin, as partial failures are common and would result in a 'no' resolution.
How this number is built
| Deadline | 2027-01-31 |
| Base rate | 60% |
| Best evidence | tier 4 · 5 article(s) used |
| Independent runs | 65 · 67 (spread 2 pts) |
| Confidence | medium |
| Evidence cap | not triggered |
| Last revised | 2026-10-03 09:03 |
| Model | qwen/qwen3.8-27b (Groq) |
Sources consulted
Probability history
2026-10-03 09:03 66% 8 article(s) on file · qwen/qwen3.8-27b (Groq)
- What pushes it up. Vaxcyte has narrowed the guidance for topline data to late October 2026, which is well before the January 2027 deadline [4].
- What pushes it up. The company recently released preliminary safety, tolerability, and immunogenicity data, suggesting the trial is progressing as planned [4].
- What pushes it up. Vaxcyte has a track record of successful high-valency vaccines (VAX-20), which increases the prior probability of success for VAX-31 [1].
- What pushes it down. All provided press articles are Tier 4 (aggregators/pickups) and lack direct Tier 1 or 2 confirmation of the specific non-inferiority outcome, only confirming the timeline [4].
- What pushes it down. The starting state notes that partial failures on a few serotypes are common in this class, which would count as a 'no' under the resolution criteria [1].
- What would move this number most. Whether the immunogenicity data for all 31 serotypes meets the non-inferiority margin, as partial failures are common and would result in a 'no' resolution.
2026-09-19 07:40 70% 4 article(s) on file · gemini-3.6-flash
Reasons not recorded for this revision (detailed history has only been kept since recently).
Post-mortem
Now that this question is resolved, each revision can be scored against the actual outcome.
| 2026-09-19 07:40 | gemini-3.6-flash | 70% | 0.09 |
| 2026-10-03 09:03 | qwen/qwen3.8-27b (Groq) | 66% | 0.116 |
- gemini-3.6-flash — n=1, average Brier score 0.09
- qwen/qwen3.8-27b (Groq) — n=1, average Brier score 0.116
Sample still too small to draw a general pattern from (rule of thumb: n≈40) — this table states facts, it does not conclude anything.