Virology Capabilities Test (VCT)
Models answer 322 multimodal virology troubleshooting questions written by expert virologists. Multiple-select variant requires all correct options.
Anthropic cards call it Multimodal virology and use the multiple-select variant.
- Made by
- SecureBio and Center for AI Safety
- Released
- April 2025
- Kind
- Hazardous knowledge
- Level
- Expert
- Scored
- Checked automatically
- Answers
- Multiple choice
- Tasks
- Public, plus a private test set
- Strongest model tested
- GPT-6 Astra #3 on the capability index
- Last in a launch post
- March 2026, dropped before it saturated
- Last model added
- October 2026
- Scores refreshed
- November 12th, 2026
In the authors’ words
We present the Virology Capabilities Test (VCT), a large language model (LLM) benchmark that measures the capability to troubleshoot complex virology laboratory protocols. Constructed from the inputs of dozens of PhD-level expert virologists, VCT consists of 322 multimodal questions covering fundamental, tacit, and visual knowledge that is essential for practical work in virology laboratories. VCT is difficult: expert virologists with access to the internet score an average of 22.1% on questions specifically in their sub-areas of expertise. However, the most performant LLM, OpenAI's o3, reaches 43.8% accuracy, outperforming 94% of expert virologists even within their sub-areas of specialization. The ability to provide expert-level virology troubleshooting is inherently dual-use: it is useful for beneficial research, but it can also be misused. Therefore, the fact that publicly available models outperform virologists on VCT raises pressing governance considerations. We propose that the capability of LLMs to provide expert-level troubleshooting of dual-use virology work should be integrated into existing frameworks for handling dual-use technologies in the life sciences.
Grok 4.6 leads with 67.4%
Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.
o3 leads with 43.8% across all independent runs
Best score per model across the official leaderboard, Epoch AI’s own runs and any board Epoch AI copied. Each bar and row names its source.
Grok 4.6 leads with 67.4%, claims included
Best score per model from every source, including labs’ own numbers and claims Epoch AI collected from reports and papers. Labs pick their own settings, so a claim can beat an independent run of the same model.
- 67.4 Grok 4.6
- 65.5 Grok 4.5
- 63.0 Grok 4.7
- 61.0 Grok 4.1
- 60.0 Grok 4
- 59.0 Claude Opus 5
- 59.0 Claude Opus 5.5
- 58.0 Claude Fable 5.1
- 58.0 Claude Sonnet 5.5
- 57.8 GPT-6 Astra
- 57.4 Claude Mythos Preview
- 55.9
Muse Wonder Full
- 54.5 Grok 4 Fast
- 54.0 Grok 4.20
- 53.5 GPT-5.6 Sol
- 52.0
Muse Spark 1.1
- 52.0 Beam 1.0
- 51.7
Muse Spark 1.3
- 50.0 Claude Opus 4.7
- 49.7
Muse Spark
- 48.3 Claude Opus 4.6
- 48.0 Claude Haiku 5.5
- 47.7 Claude Opus 4.5
- 47.0 Claude Opus 4.8
- 45.0 Claude Sonnet 5
- 41.4 GPT-5
- 39.7 Claude Sonnet 4.5
- 39.7 Claude Sonnet 4.6
- 32.0 Claude Haiku 4.5
- 28.7 grok-code-fast-1
- 23.8
Code World Model (CWM)
- 1 Grok 4.6 67.4%
- 2 Grok 4.5 65.5%
- 3 Grok 4.7 63%
- 4 Grok 4.1 61%
- 5 Grok 4 60%
- 6 Claude Opus 5 59%
- 7 Claude Opus 5.5 59%
- 8 Claude Fable 5.1 58%
- 9 Claude Sonnet 5.5 58%
- 10 GPT-6 Astra 57.8%
- 11 Claude Mythos Preview 57.4%
- 12
Muse Wonder Full 55.9%
- 13 Grok 4 Fast 54.5%
- 14 Grok 4.20 54%
- 15 GPT-5.6 Sol 53.5%
- 16
Muse Spark 1.1 52%
- 17 Beam 1.0 52%
- 18
Muse Spark 1.3 51.7%
- 19 Claude Opus 4.7 50%
- 20
Muse Spark 49.7%
- 21 Claude Opus 4.6 48.3%
- 22 Claude Haiku 5.5 48%
- 23 Claude Opus 4.5 47.7%
- 24 Claude Opus 4.8 47%
- 25 Claude Sonnet 5 45%
- 26 GPT-5 41.4%
- 27 Claude Sonnet 4.5 39.7%
- 28 Claude Sonnet 4.6 39.7%
- 29 Claude Haiku 4.5 32%
- 30 grok-code-fast-1 28.7%
- 31
Code World Model (CWM) 23.8%
Source: Labs’ model cards
- 1 o3 43.8%
- 2
Gemini 2.5 Pro Mar 2025 37.6%
- 3 o4-mini 37%
- 4 o1 35.4%
- 5 Claude 3.7 Sonnet 30.8%
- 6 GPT-4.5 28.3%
- 7 GPT-4o Mar 2025 18.8%
Source: Official Virology Capabilities Test (VCT) leaderboard
- 67.4 Grok 4.6
- 65.5 Grok 4.5
- 63.0 Grok 4.7
- 61.0 Grok 4.1
- 60.0 Grok 4
- 59.0 Claude Opus 5
- 59.0 Claude Opus 5.5
- 58.0 Claude Fable 5.1
- 58.0 Claude Sonnet 5.5
- 57.8 GPT-6 Astra
- 57.4 Claude Mythos Preview
- 55.9
Muse Wonder Full
- 54.5 Grok 4 Fast
- 54.0 Grok 4.20
- 53.5 GPT-5.6 Sol
- 52.0
Muse Spark 1.1
- 52.0 Beam 1.0
- 51.7
Muse Spark 1.3
- 50.0 Claude Opus 4.7
- 49.7
Muse Spark
- 48.3 Claude Opus 4.6
- 48.0 Claude Haiku 5.5
- 47.7 Claude Opus 4.5
- 47.0 Claude Opus 4.8
- 45.0 Claude Sonnet 5
- 43.8 o3
- 41.4 GPT-5
- 39.7 Claude Sonnet 4.5
- 39.7 Claude Sonnet 4.6
- 37.6
Gemini 2.5 Pro
- 37.0 o4-mini
- 35.4 o1
- 32.0 Claude Haiku 4.5
- 30.8 Claude 3.7 Sonnet
- 28.7 grok-code-fast-1
- 28.3 GPT-4.5
- 23.8
Code World Model (CWM)
- 18.8 GPT-4o
- 1 Grok 4.6 67.4%
- 2 Grok 4.5 65.5%
- 3 Grok 4.7 63%
- 4 Grok 4.1 61%
- 5 Grok 4 60%
- 6 Claude Opus 5 59%
- 7 Claude Opus 5.5 59%
- 8 Claude Fable 5.1 58%
- 9 Claude Sonnet 5.5 58%
- 10 GPT-6 Astra 57.8%
- 11 Claude Mythos Preview 57.4%
- 12
Muse Wonder Full 55.9%
- 13 Grok 4 Fast 54.5%
- 14 Grok 4.20 54%
- 15 GPT-5.6 Sol 53.5%
- 16
Muse Spark 1.1 52%
- 17 Beam 1.0 52%
- 18
Muse Spark 1.3 51.7%
- 19 Claude Opus 4.7 50%
- 20
Muse Spark 49.7%
- 21 Claude Opus 4.6 48.3%
- 22 Claude Haiku 5.5 48%
- 23 Claude Opus 4.5 47.7%
- 24 Claude Opus 4.8 47%
- 25 Claude Sonnet 5 45%
- 26 o3 43.8%
- 27 GPT-5 41.4%
- 28 Claude Sonnet 4.5 39.7%
- 29 Claude Sonnet 4.6 39.7%
- 30
Gemini 2.5 Pro Mar 2025 37.6%
- 31 o4-mini 37%
- 32 o1 35.4%
- 33 Claude Haiku 4.5 32%
- 34 Claude 3.7 Sonnet 30.8%
- 35 grok-code-fast-1 28.7%
- 36 GPT-4.5 28.3%
- 37
Code World Model (CWM) 23.8%
- 38 GPT-4o Mar 2025 18.8%
Sources: Labs’ model cards and official Virology Capabilities Test (VCT) leaderboard
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | Grok 4.6 | 67.4% | Aug 2026 | Lab model card | |
| 2 | Grok 4.5 | 65.5% | Jul 2026 | Lab model card | |
| 3 | Grok 4.7 | 63% | Sep 2026 | Lab model card | |
| 4 | Grok 4.1 | 61% | Nov 2025 | Lab model card | |
| 5 | Grok 4 | 60% | Aug 2025 | Lab model card | |
| 6 | Claude Opus 5 | 59% | Jul 2026 | Lab model card | |
| 7 | Claude Opus 5.5 | 59% | Sep 2026 | Lab model card | |
| 8 | Claude Fable 5.1 | 58% | Sep 2026 | Lab model card | |
| 9 | Claude Sonnet 5.5 | 58% | Sep 2026 | Lab model card | |
| 10 | GPT-6 Astra | 57.8% | Sep 2026 | Lab model card | |
| 11 | Claude Mythos Preview | 57.4% | Apr 2026 | Lab model card | |
| 12 | | 55.9% | Oct 2026 | Lab model card | |
| 13 | Grok 4 Fast | 54.5% | Sep 2025 | Lab model card | |
| 14 | Grok 4.20 | 54% | Mar 2026 | Lab model card | |
| 15 | GPT-5.6 Sol | 53.5% | Jun 2026 | Lab model card | |
| 16 | | 52% | Jul 2026 | Lab model card | |
| 17 | Beam 1.0 | 52% | Oct 2026 | Lab model card | |
| 18 | | 51.7% | Oct 2026 | Lab model card | |
| 19 | Claude Opus 4.7 | 50% | Apr 2026 | Lab model card | |
| 20 | | 49.7% | Jun 2026 | Lab model card | |
| 21 | Claude Opus 4.6 | 48.3% | Feb 2026 | Lab model card | |
| 22 | Claude Haiku 5.5 | 48% | Oct 2026 | Lab model card | |
| 23 | Claude Opus 4.5 | 47.7% | Nov 2025 | Lab model card | |
| 24 | Claude Opus 4.8 | 47% | May 2026 | Lab model card | |
| 25 | Claude Sonnet 5 | 45% | Jun 2026 | Lab model card | |
| 26 | GPT-5 | 41.4% | Aug 2025 | Lab model card | |
| 27 | Claude Sonnet 4.5 | 39.7% | Sep 2025 | Lab model card | |
| 28 | Claude Sonnet 4.6 | 39.7% | Feb 2026 | Lab model card | |
| 29 | Claude Haiku 4.5 | 32% | Oct 2025 | Lab model card | |
| 30 | grok-code-fast-1 | 28.7% | Aug 2025 | Lab model card | |
| 31 | | 23.8% | Oct 2025 | Lab model card |
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | o3 | 43.8% | Apr 2025 | Official leaderboard | |
| 2 | | 37.6% | Mar 2025 | Official leaderboard | |
| 3 | o4-mini | 37% | Apr 2025 | Official leaderboard | |
| 4 | o1 | 35.4% | Dec 2024 | Official leaderboard | |
| 5 | Claude 3.7 Sonnet | 30.8% | Feb 2025 | Official leaderboard | |
| 6 | GPT-4.5 | 28.3% | Feb 2025 | Official leaderboard | |
| 7 | GPT-4o Mar 2025 | 18.8% | Mar 2025 | Official leaderboard |
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | Grok 4.6 | 67.4% | Aug 2026 | Lab model card | |
| 2 | Grok 4.5 | 65.5% | Jul 2026 | Lab model card | |
| 3 | Grok 4.7 | 63% | Sep 2026 | Lab model card | |
| 4 | Grok 4.1 | 61% | Nov 2025 | Lab model card | |
| 5 | Grok 4 | 60% | Aug 2025 | Lab model card | |
| 6 | Claude Opus 5 | 59% | Jul 2026 | Lab model card | |
| 7 | Claude Opus 5.5 | 59% | Sep 2026 | Lab model card | |
| 8 | Claude Fable 5.1 | 58% | Sep 2026 | Lab model card | |
| 9 | Claude Sonnet 5.5 | 58% | Sep 2026 | Lab model card | |
| 10 | GPT-6 Astra | 57.8% | Sep 2026 | Lab model card | |
| 11 | Claude Mythos Preview | 57.4% | Apr 2026 | Lab model card | |
| 12 | | 55.9% | Oct 2026 | Lab model card | |
| 13 | Grok 4 Fast | 54.5% | Sep 2025 | Lab model card | |
| 14 | Grok 4.20 | 54% | Mar 2026 | Lab model card | |
| 15 | GPT-5.6 Sol | 53.5% | Jun 2026 | Lab model card | |
| 16 | | 52% | Jul 2026 | Lab model card | |
| 17 | Beam 1.0 | 52% | Oct 2026 | Lab model card | |
| 18 | | 51.7% | Oct 2026 | Lab model card | |
| 19 | Claude Opus 4.7 | 50% | Apr 2026 | Lab model card | |
| 20 | | 49.7% | Jun 2026 | Lab model card | |
| 21 | Claude Opus 4.6 | 48.3% | Feb 2026 | Lab model card | |
| 22 | Claude Haiku 5.5 | 48% | Oct 2026 | Lab model card | |
| 23 | Claude Opus 4.5 | 47.7% | Nov 2025 | Lab model card | |
| 24 | Claude Opus 4.8 | 47% | May 2026 | Lab model card | |
| 25 | Claude Sonnet 5 | 45% | Jun 2026 | Lab model card | |
| 26 | o3 | 43.8% | Apr 2025 | Official leaderboard | |
| 27 | GPT-5 | 41.4% | Aug 2025 | Lab model card | |
| 28 | Claude Sonnet 4.5 | 39.7% | Sep 2025 | Lab model card | |
| 29 | Claude Sonnet 4.6 | 39.7% | Feb 2026 | Lab model card | |
| 30 | | 37.6% | Mar 2025 | Official leaderboard | |
| 31 | o4-mini | 37% | Apr 2025 | Official leaderboard | |
| 32 | o1 | 35.4% | Dec 2024 | Official leaderboard | |
| 33 | Claude Haiku 4.5 | 32% | Oct 2025 | Lab model card | |
| 34 | Claude 3.7 Sonnet | 30.8% | Feb 2025 | Official leaderboard | |
| 35 | grok-code-fast-1 | 28.7% | Aug 2025 | Lab model card | |
| 36 | GPT-4.5 | 28.3% | Feb 2025 | Official leaderboard | |
| 37 | | 23.8% | Oct 2025 | Lab model card | |
| 38 | GPT-4o Mar 2025 | 18.8% | Mar 2025 | Official leaderboard |
The benchmark's own leaderboard has 7 models. Switch the scores above to rank them together.
5 models have held number one in labs’ own numbers since its release in April 2025 2 models have held number one across all independent runs since its release in April 2025 6 models have held number one with claims included since its release in April 2025
Lab claims count from the day the card came out, independent runs from the model’s release. We draw one row each for the benchmark’s own leaderboard and what labs claim in their cards.
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Sources: Official Virology Capabilities Test (VCT) leaderboard and labs’ model cards
Labs headline it less often now, last in March 2026
Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.
| Date | Launch post | Score | As the post writes it |
|---|---|---|---|
| Mar 9, 2026 | Grok 4.20 | 54 | Virology Capabilities Test, accuracy 0.54, Grok 4.2 SA, Table 4 |
35 system cards report it, from 5 labs
Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.
| Date | Document | Score | As the document writes it | Section |
|---|---|---|---|---|
| Oct 23, 2026 | | 51.7 | VCT accuracy, Muse Spark 1.3 (API) max, multiple-response MC (Table 1, Figure 1) | Bio and chem risk |
| Oct 12, 2026 | | 55.9 | SecureBio VCT (CBRN Capability Evaluations table, section 4) | Bio and chem risk |
| Oct 7, 2026 | Claude Haiku 5.5 system card | 48 | Multimodal virology (VCT), accuracy 0.48 on the 350-question set, printed on chart (Figure 2.2.2.A) | Bio and chem risk |
| Oct 5, 2026 | Beam 1.0 technical report | 52 | SecureBio VCT V2 exact-match accuracy | Bio and chem risk |
| Sep 28, 2026 | Claude Sonnet 5.5 system card | 58 | Multimodal virology (VCT), accuracy 0.58 on the 350-question set (2.2.2, Figure 2.2.2.A) | Bio and chem risk |
| Sep 22, 2026 | Claude Opus 5.5 system card | 59 | Multimodal virology (VCT), accuracy 0.59 on the 350-question set, highest-scoring snapshot (2.2.3.1, Figure 2.2.3.1.A) | Bio and chem risk |
| Sep 21, 2026 | Grok 4.7 model card | 63 | Virology Capabilities Test (VCT), accuracy, high, without safeguards (7.2) | Bio and chem risk |
| Sep 3, 2026 | GPT-6 Astra system card | 57.8 | SecureBio VCT, refusal-corrected accuracy, pre-release checkpoint (10.1.1.4) | Bio and chem risk |
| Sep 1, 2026 | Claude Fable 5.1 system card | 58 | Multimodal Virology VCT, Mythos 5.1 | Other |
| Aug 12, 2026 | Grok 4.6 model card | 67.4 | Virology Capabilities Test (VCT), accuracy, high, without safeguards (8.1) | Bio and chem risk |
| Jul 24, 2026 | Claude Opus 5 system card | 59 | Multimodal virology (VCT), score 0.59, highest-scoring snapshot (2.2.4, Figure 2.2.4.A) | Bio and chem risk |
| Jul 14, 2026 | Grok 4.5 model card | 65.5 | Virology Capabilities Test (VCT), accuracy, high, without safeguards (8.1) | Bio and chem risk |
| Jul 9, 2026 | GPT-5.6 Sol system card | 53.5 | SecureBio Virology Capabilities Test, strongest reported configuration of Sol or its railfree version (9.1.1.8) | Bio and chem risk |
| Jul 9, 2026 | | 52 | VCT, Muse Spark 1.1 Helpful (Table 1, Figure 1) | Bio and chem risk |
| Jun 30, 2026 | Claude Sonnet 5 system card | 45 | Multimodal virology (VCT), score 0.45, expert baseline 0.221 (2.2.4) | Bio and chem risk |
| Jun 25, 2026 | GPT-5.6 Sol system card | 53.5 | SecureBio Virology Capabilities Test, strongest reported configuration of Sol or its railfree version (9.1.1.8) | Bio and chem risk |
| Jun 12, 2026 | | 49.7 | VCT (Table 1, Figure 1) | Bio and chem risk |
| May 28, 2026 | Claude Opus 4.8 system card | 47 | Multimodal virology (VCT), Virology Capabilities Test score 0.470 (Table 2.2.3.B, 2.2.4) | Bio and chem risk |
| Apr 16, 2026 | Claude Opus 4.7 system card | 50 | Multimodal virology (VCT), score 0.50, highest score across snapshots, printed on chart (2.2.5.2, Figure 2.2.5.2.A) | Bio and chem risk |
| Apr 7, 2026 | Grok 4.20 model card | 54 | Virology Capabilities Test, accuracy 0.54, Grok 4.2 SA, Table 4 | Safety |
| Apr 7, 2026 | Claude Mythos Preview system card | 57.4 | Multimodal virology (VCT), score 0.574 (2.2.5.4, Figure 2.2.5.4.A) | Bio and chem risk |
| Feb 17, 2026 | Claude Sonnet 4.6 system card | 39.7 | Multimodal virology (VCT), multiple select variant, mean score 0.397 (6.2.2.2) | Bio and chem risk |
| Feb 5, 2026 | Claude Opus 4.6 system card | 48.3 | Multimodal virology (VCT), multiple select variant, mean score 0.483 (8.2.4.2) | Bio and chem risk |
| Nov 24, 2025 | Claude Opus 4.5 system card | 47.7 | Multimodal virology (VCT), multiple select variant, mean score 0.4771 (7.2.4.2) | Bio and chem risk |
| Nov 17, 2025 | Grok 4.1 model card | 61 | VCT, accuracy 0.61, text-only questions, Grok 4.1 Thinking, safeguards removed (Table 4) | Bio and chem risk |
| Oct 15, 2025 | Claude Haiku 4.5 system card | 32 | VMQA/VCT, score 0.32 (6.2.3.1) | Bio and chem risk |
| Oct 8, 2025 | | 23.8 | VCT, text-only subset of 101 questions (Table 13) | Bio and chem risk |
| Sep 29, 2025 | Claude Sonnet 4.5 system card | 39.7 | Multimodal virology (VMQA/VCT), multiple select, 10-shot, 39.7% (9.2.4.2, Figure 9.2.4.2.A 0.397) | Bio and chem risk |
| Sep 19, 2025 | Grok 4 Fast model card | 54.5 | VCT, accuracy 54.5, text-only portion (Table 3) | Bio and chem risk |
| Aug 26, 2025 | grok-code-fast-1 model card | 28.7 | VCT, accuracy 28.7 (Table 3) | Bio and chem risk |
| Aug 20, 2025 | Grok 4 model card | 60 | VCT, accuracy 0.60, text-only portion, Grok 4 API (Table 3) | Bio and chem risk |
| Aug 7, 2025 | GPT-5 system card | 41.4 | SecureBio Virology Capabilities Test, gpt-5-thinking July 13, mean of n=10 (Table 15) | Bio and chem risk |
| May 22, 2025 | Claude Sonnet 4 system card | Multimodal virology VMQA/VCT, multiple select, 0, 5 and 10 shots, extended thinking, chart without printed values (Figure 7.2.4.4.A) | Bio and chem risk | |
| May 22, 2025 | Claude Opus 4 system card | Multimodal virology VMQA/VCT, multiple select, 0, 5 and 10 shots, extended thinking, chart without printed values (Figure 7.2.4.4.A) | Bio and chem risk | |
| Feb 24, 2025 | Claude 3.7 Sonnet system card | Multimodal virology (VCT), multiple select, 0 and 5 shots with Bo1 to Bo10, 32k thinking, chart without printed values. Text says above the human baseline (Figure 16) | Bio and chem risk |
Versions
We switch the top row to each new version when it comes out. Open it for one row per version. An old version stays in play while people still test it, so whoever first takes it past 85% gets credit for closing it out.
Sources: Official leaderboards and labs’ model cards
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