Time window. The prediction covers roughly August 1–October 31, 2020.

What actually happened.

Upside vaccine news in that period:

• Pfizer/BioNTech (Aug 20, 2020): Released Phase 1 data showing strong neutralizing antibody responses in younger and older adults and signaled they were on track to seek regulatory review as early as October, with plans to supply up to 100 million doses by end of 2020 and 1.3 billion in 2021. (pfizer.com)
• Moderna (Sep 29, 2020): Published Phase 1 data in older adults showing mRNA‑1273 induced high neutralizing antibody titers in age 56–70 and 71+ cohorts, with the vaccine generally well tolerated—messaged as providing “optimism” about protecting high‑risk groups. (investors.modernatx.com)
• Timeline/rollout optimism (early Sept 2020): Pfizer’s CEO publicly said the company could have initial efficacy results by late October and be ready to quickly seek FDA authorization if results were positive. Around the same time, CDC asked states to prepare for possible vaccine distribution as early as early November, reported as giving “optimism” for a vaccine while also raising concerns. (fiercepharma.com)

Downside / negative vaccine news and framing:

• AstraZeneca trial pause (Sept 8, 2020): Its Oxford AZD1222 Phase 3 trial was put on hold globally after a participant developed an unexplained serious illness, widely covered as a safety-related setback. (pharmtech.com)
• Johnson & Johnson trial pause (Oct 12, 2020): J&J’s large Phase 3 trial was likewise paused for an unexplained illness in a participant, another headline "pause" that fueled public concern about vaccine safety. (cnbc.com)
• Overall tone of U.S. COVID coverage (including vaccines): A National Bureau of Economic Research analysis of English‑language COVID‑19 articles in 2020 found that 91% of stories from major U.S. outlets were negative in tone, and that this unusually high negativity persisted even in areas with positive scientific developments like vaccine trials. (nber.org) This indicates that even when data from vaccine trials were scientifically promising, mainstream coverage tended to emphasize risks, uncertainties, and controversies rather than good news.

Evaluation against the prediction. The predictor asserted that over the next 2–3 months people would “for sure” hear more upside than downside news on vaccines. In reality:

• There were several high-profile positive trial updates and optimistic timelines from Pfizer, Moderna, and U.S. agencies. (pfizer.com)
• But there were also very salient negative events (AstraZeneca and J&J trial pauses) that dominated headlines, and robust empirical analysis shows that U.S. COVID‑19 news overall—including vaccine‑trial coverage—remained overwhelmingly negative in tone even when science was progressing. (pharmtech.com)

Given that mainstream audiences in this period were exposed to vaccine stories framed largely with caution and concern, and that the best available quantitative evidence shows persistent negativity even around vaccine trials, the claim that upside vaccine news would clearly outweigh downside news did not come true.