You are correct regarding remote material cooperation. Most Catholics are unaware of this principle in Catholic morality.
But is there a "proportionately serious reason to do so" when the vaccine does come out? Check out Christoper Ferrara's graphics in the article below.
MASK DELUSION: Why that useless piece of cloth on your face means the end of civil society
Here's just one example:
Pope Francis, the UN and WHO are milking this scamdemic.
Finally, how many various vaccines will be finally available? Will we have a choice? And if it's one, single NWO universal vaccine, who makes that decision? Bill Gates?