The old military maxim of “hurry up and wait” may apply to the promising new COVID-19 vaccine the Army is developing.

Word that scientists at the Walter Reed Army Institute of Research have developed a vaccine that offers promising early results against all COVID-19 strains got out Wednesday, sparking fresh optimism amid the raging omicron variant. But experts caution further clinical research is needed to prove its efficacy in humans and that America may be a long way from new shots.