Medicaid Questions

I'm new to the Medicaid program. After I lost my job, I applied to have my son be covered by Medicaid health care benefits. He was accepted and I've got his ID card and everything. 
What will the Medicaid cover for my son? Co-pays? WC visits? I'm concerned about him getting off track of his vaccine schedule (he's overdue already for his 12 mo vaccines) but I don't have money for co-payments. Will Medicaid cover that?