CNN:

And both the Trump Administration and the incoming Biden Administration want to release all available doses

immediately instead of holding half of them back to ensure that people who've already gotten the first dose will be able to get the second on time.

The benefit is that this will make more vaccines available in the short term.

The drawback is that it risks people not being able to get their second dose when health officials say they should have it.

对于 it risks people not being able to get their second dose when health officials say they should have it.疑问：

1）这里的not being able to get their second dose when health officials say they should have it 是非谓语表原因状语吧？

即上句可改写成： Not being able to get their second dose when health officials say they should have it, it risks people.

对吗？

2）该句中的when 是当...时候的意思吗？

在when前是否省略了at the time when...?   即：

it risks people not being able to get their second dose AT THE TIME when health officials say they should have it.

3) 这里的when可以用while = 然而 替换 吗？