Both are needed.
People who believe its God’s will for humans to be deformed, crippled and sick are anti-spiritual.
God gave us brains and physicians to heal us.
God has a desirous will and a permissive will.
Humanity is in a pickle already of having rebelled in spirit against the Lord. The Lord permitted it but He never desired it. However permitting it was the only way He could let love have a voluntary aspect and not be a robotic Kabuki dance.
The complex result of this and the Lord’s desire to redeem mankind is the reason for the sometimes baffling scenes we see.
Should people immunize. The answer is a resounding maybe.
And the science is settled...