Coronavirus vaccines for children younger than 5 could be available far sooner than expected - perhaps by the end of February - under a plan that would lead to the potential authorization of a two-shot regimen in the coming weeks, people briefed on the situation said Monday. Pfizer and its partner, BioNTech, the manufacturers of the vaccine, are expected to submit to the Food and Drug Administration as early as Tuesday a request for emergency use authorization for the vaccine for children six mo