Are they useful at the start of a new variant? For example if we assume it gets to the US eventually, what is, say, an extra few weeks buying the US? On day 1

Are they useful at the start of a new variant? For example if we assume it gets to the US eventually, what is, say, an extra few weeks buying the US? On day 1 or in year 1, I see the value in those weeks. You can build ventilators, field hospitals, and learn treatments. At this point, are there new useful ways to use a few weeks of lead time?