As rollout falters, scientists debate new vaccination tactics

U.S. scientists are considering alternative strategies to achieve widespread COVID-19 vaccination with limited supplies, as initial efforts have left far fewer Americans protected at this point than anticipated. An estimated 14 million doses of the Pfizer and Moderna vaccines have shipped nationwide, yet only 4.2 million people had received the first of two doses as of January 2. Although receiving even one dose offers some measure of protection against the virus, health officials here balk at the idea of administering a single dose to as many people as possible now and holding off on booster doses until later. Britain has already chosen that option, which theoretically doubles the number of initial doses, but U.S. officials worry the approach could curb public confidence in the vaccines and possibly even promote new strain development. They are somewhat more receptive to possibly giving some Americans two half-doses of the Moderna vaccine, which might allow them to optimize immunity from the available supply of vaccine while expediting distribution and saving more lives. Experts warn, though, that making more initial doses available will not have an effect where distribution delays are a byproduct of logistical hurdles.