Start with high-confidence children's health books, then narrow by subgenre or adjacent topics.
Healthy Kids, Happy Kids
Elisa Song M.D.
In Control
Jean Betschart-Roemer, Susan Thom
Vaccinations: a Thoughtful Parent's Guide
Aviva Jill Romm
The Vaccine-friendly Plan
Paul Thomas M.D., Jennifer Margulis
The Deepest Well
Nadine Burke Harris