If everybody were vaccinated, then any potential side effects could be put off as "chronic or genetic" diseases.
Could help build blind faith in future vaccines with potentially deadlier outcomes, or pave the ground for selective annihilation.
The reason I don't think the current vaccine will depopulate the earth is because the cabal certainly does not want the sheep to go extinct, with all of us remaining in tact. The above would then provide one potential way to close the gaps in what seems like an over the top push for getting vaccinated despite well knowing that so many of us will never take it.
Since they just ignore anything that doesn't fit their narrative, which they're already doing about the side effects, I don't know why they'd have to make the effort to mask them. More likely they just want as many people as possible injected with their death potion.