With More Vaccines Secured, Biden Warns of Hurdles to Come

The Biden administration said Thursday it had secured 200 million more doses of coronavirus vaccines, enough to inoculate every American adult, but President Biden warned that logistical hurdles would most likely mean that many Americans will still not have been vaccinated by the end of the summer.

The additional doses amount to a 50 percent increase in vaccine, and will give the administration the number of doses that Mr. Biden said last month he needs to cover 300 million people by the end of the summer. But it will still...