evidence: Russia asks China for military and economic aid, an American journalist is killed by Russian forces in Ukraine, and more - 1. Russia requests military and economic aid from China - 2. U.S. journalist Brent Renaud killed by Russian forces - 3. Zelensky: Ukrainian negotiators tasked with setting up Putin meeting - 4. Pentagon: No U.S. personnel were at Ukrainian base near Poland during Russia strike - 5. Obama tests positive for COVID-19 - 6. Ukraine says power restored to Chernobyl nuclear plant - 7. Pfizer CEO says 4th coronavirus booster will be needed for future variants - 8. Russia threatens to arrest leaders and seize assets of Western companies - 9. Tom Brady says he's returning to NFL 40 days after announcing retirement - 10. Actor William Hurt dies at 71 1. Russia requests military and economic aid from China [...] Pfizer CEO Albert Bourla said Sunday that it would be necessary for people to receive a fourth dose of the company's coronavirus vaccine as the pandemic continues. "Many variants are coming, and Omicron was the first one that was able to evade — in a skillful way — the immune protection that we're giving," Bourla said on CBS' Face the Nation. Bourla said full vaccination with the two-dose vaccine and a booster shot is "actually quite good for hospitalizations and deaths," but "not that good against infections" and "doesn't last very long" against a variant like Omicron. The company, which developed its vaccine with partner BioNTech, is working on a fourth dose that would be effective against all variants.