Charlie/Claire injections

[Lpspider]

What was up with the Vaccine? I don't remember the lost creators every showing them find it... so Charlie randomly has some vaccine? Is this the same thing that Desmond was taking before?

[Michelle]

it probably is the stuff desmond was injecting before, maybe he found it in the hatch while looking for his drugs

[Lpspider]

Yeah, but why would they, charlie and claire, both simply just accept it without asking jack or anything?