keir simmons, nbc news, wales. >> so things happening in the uk. and here in the u.s. an fda review suggests the pfizer vaccine may even be more effective than first thought as an fda outside panel prepares to meet thursday on whether to approve the vaccine here tom costello has more. >> reporter: 36 hours ahead of the outside advisory panel's meeting the fda says its review of the data suggests pfizer's covid vaccine is very promising. while everyone needs two shots, the vaccine was 50% effective after the first dose 95% effective after the second and effective across all age and ethnic groups, even for people with underlying conditions like obesity, diabetes, and high blood pressure. but will there be enough vaccine pfizer says it can't ship more doses to the u.s. until next summer because other countries bought up supplies first the white house passed up a chance to buy more last summer because, says president trump's former fda chief, the u.s. was counting on