"When the rate of vaccination within a population is greater than 92%, outbreaks of measles typically no longer occur; however, they may occur again if the rate of vaccination decreases." https://en.wikipedia.org/wiki/Measles_vaccine
Of course she's doubling down. Anything else would mean facing the extent of her responsibility in the death of her child, which would be absolutely crushing to her ego and self-image as a parent.
She's protecting herself psychologically, that's not surprising.
It's simpler than that. Reversing her position would (1) burn her relationships with most of her social graph, and (2) paint a big target on her back...when nasty anti-vaxers are enjoying a strong tail wind from Washington.
In other news, very few victims of armed robbery say "over my dead body, thief!".
I doubt that either of the parents have (1) or (2) in their mindset/decisioning tree. This is just Darwinism in full effect. Nature has a habit of shaking off the weak, and the weak minded.
For folks outside of the United States - this is the level of stupid we're dealing with here. I'm just glad I'm old enough to remember when the United States was actually great, great because of strong democratic institutions, civic duty, and excellent engineering.
One thing that struck me when looking deeper into conspiracy theories is how some people manage to seek out the wrong truths, the blatant lies with apparent ease, like as if you could mix any number of true and proven statements from textbooks and science publications and hide a single fake one in there and people so inclined would always pick the lie and reject the truths as suspicious. It's almost as if it was really working in a backwards way, as though flat-earthers knew darn well that of course the world is undoubtedly round, and contrails are not 'chemtrails', which is precisely why they reject these views, as though their minds had developed an auto-immunity disorder. On a related note, a good portion of votes in the last^W latest U.S. election also apparently came from voters who tossed a ballot against their own best interest (65% voted for GOP in the town where they allegedly 'eat the dogs and cats').
I recall many years ago when the anti-VAX stuff wasn’t quite front and center a celebrity said that her child got autism from a vaccine. A quote that stuck out to me was that her story was that her mother’s instinct told her getting the vaccine was wrong before the child was vaccinated… but she didn’t listen.
There’s some belief for suspicion or something about these folks long before they even have an experience that sets them up for this line of thinking.