I wouldn't say the vacuum is a huge concern. Serostim has no vacuum at all and never has.
That's because it's protected with a layer of non-oxidizing gas like argon or nitrogen. It's common knowledge that peptides with MET in the amino chain, like HGH and all the GLPs are highly susceptible to damage from oxygen.
All peptides start as liquid in a vial, a lyophilization stopper is installed, and moisture is removed under vacuum in the freeze drying machine. The stopper acts as a "one way valve", leaving behind vacuum, which also protects the peptide from oxidative damage. Pharma goes one step further, and replaces the vacuum with oxygen free gas, which protected the peptide more, and without vacuum trying to suck in, means even if the seal isn't perfect it's unlikely to be contaminated with air.
If there's no vacuum it was somehow lost, with the only practical explanation being the stopper didn't create a perfect seal, and unsterile air was sucked in.
Unfortunately we now have unscrupulous vendors (
@TheLobster), bolstered by some ignorant members gaslighting the community into believing we should no longer be concerned about vacuum in peptides.
They pinned it and didn't end up in the hospital so it's fine.
If you have vials without vacuum, you've been sold a low quality, defective product and are entitled to a replacement or refund. Without vacuum, it will degrade much more quickly than with.