do you see the vaccine becoming politicized? >> i'm hoping that political leaders across the entire political aisle not turn this into a -- you know, red state or a blue state issue. >> reporter: the study finding limited side effects, especially when volunteers took acetaminophen. and with no signs of the pandemic slowing down, the oxford researchers say they know the pressure is on to create an effective vaccine as quickly and as safely as possible. >> we feel that there's urgency and pressure, really, every day, so people are working day and night, they're working weekends. and we're not going to stop until we get an answer. >> reporter: now, david, most experts believe the vaccine could be ready by the end of the year, early 2021, but we have to remember, it is first going to be made available to the most vulnerable in our population. widely available to all americans possibly as early as the spring. david? >> all right, tom llamas leading us off tonight. tom, thank you. of course, cases rising in 40 states tonight. the trouble with testing and the raging debate continuing over opening schools.