If anything kills over 10 million people in the next few decades, it will most likely be a highly infectious virus rather than a war.

Judge at a horizon of three decades from 2015 (2045). The claim may resolve earlier if an event clearly settles it. Count deaths from 2015 onward. True: a single highly infectious viral outbreak (a pandemic or epidemic) is credibly estimated to have killed more than 10 million people, and no war in the same period has killed more than 10 million. Excess-mortality estimates from WHO or peer-reviewed studies count for the virus. Mostly true: a viral outbreak passes 10 million deaths only on credible excess-mortality estimates and not on confirmed counts, or a war also passes 10 million but only after the virus did and with fewer deaths. Mixed: both a virus and a war pass 10 million with similar tolls, or the event that passes 10 million is a non-viral infectious disease (for example a bacterial pandemic) and no war does. Mostly false: no event of any kind passes 10 million deaths by the horizon. The prediction is then untested, but its implied expectation did not hold. False: a war, or a cause other than an infectious disease, kills more than 10 million people and no viral outbreak does.

Set before the research began.

1. E1 14.9 million excess deaths associated with the COVID-19 pandemic in 2020 and 2021 World Health Organization · 5 May 2022

   “New estimates from the World Health Organization (WHO) show that the full death toll associated directly or indirectly with the COVID-19 pandemic (described as “excess mortality”) between 1 January 2020 and 31 December 2021 was approximately 14.9 million (range 13.3 million to 16.6 million).”

2. E2 The WHO estimates of excess mortality associated with the COVID-19 pandemic - Nature Nature · 14 December 2022

   “We estimate 14.83 million excess deaths globally, 2.74 times more deaths than the 5.42 million reported as due to COVID-19 for the period.”

3. E3 The WHO estimates of excess mortality associated with the COVID-19 pandemic - Nature Nature · 14 December 2022

   “Globally, for the period January 2020 to December 2021, we estimate 14.83 million excess deaths with an uncertainty interval (UI) of 13.23 million to 16.58 million”

4. E4 The WHO estimates of excess mortality associated with the COVID-19 pandemic - Nature Nature · 14 December 2022

   “However, the 1918 influenza pandemic was magnitudes higher, with an estimated 1.0% per capita excess mortality rate, or 75 million global excess deaths when adjusted to the 2020 population”

WHO estimates that about 14.9 million excess deaths (range 13.3 to 16.6 million) were associated with the COVID-19 pandemic in 2020–2021 [E1]. A peer-reviewed Nature study gives the same figure, 14.83 million [E2, E3]. So, on excess-mortality estimates, a highly infectious viral pandemic passed 10 million deaths after 2015 [E1][E3], while reported COVID-19 deaths for the period were 5.42 million [E2]; the evidence does not address war deaths. Deaths reported as due to COVID-19 for the period were only 5.42 million [E2], so the 10 million threshold is passed only on excess-mortality estimates. Under the criteria, that makes the verdict mostly true, not true.