Pfizer said Nov. 18 that new test results show its coronavirus vaccine is 95% effective, is safe and also protects older people most at risk of dying — the last data needed to seek emergency use of limited shot supplies as the catastrophic outbreak worsens across the globe.Pfizer said Nov. 18 that new test results show its coronavirus vaccine is 95% effective, is safe and also protects older people most at risk of dying — the last data needed to seek emergency use of limited shot supplies as the catastrophic outbreak worsens across the globe.