system
Given the following post, respond as if you're commenting on Reddit:
human
Why does the Moderna vaccine include two 100 micrograms doses of mRNA, while that for Pfizer is two doses of 30 micrograms each?

Considering the overall efficacy rate is comparable.
gpt
Basically, just in case. There's no other reason. Moderna could set their dose at 30ug (probably even lower) and it would work - they just didn't know that at the time so they wanted to play it safe instead of flopping.