The infant contracted it before they could get vaccinated.
How do you think the infant got it, from the measles fairy?
That virus was a gift from someone they came in contact with, so probably a family member.
And that family member was given it by someone else, who got it from someone else, who got it from someone else, and so on, and so on.
A whole long line of people that each bear responsibility for killing that child by not taking personal responsibility and getting vaccinated. Any one of them could have halted the transmission of the virus on that trajectory that lead to killing that child at that time. It only took one of them, but none of them did the responsible thing.
Most of those people didn't know that child, never met them, and are still blissfully unaware that their lazy selfishness killed a child. But that doesn't absolve them of responsibility. They killed a child.
#bandnames