No. He recognizes that some vaccines are essential, and of course has never supported the vaccine/autism connection. His position on other vaccines as non-essential and potentially harmful could be wrong, but he is not nearly as wrong as your standard anti-vaxxer.
Maher is thinking in the context of a pharmaceutical industry that has committed a few genuine blunders and schemes against health, rushing to fill people with new drugs that have disastrous side-effects and have to be recalled - all while marijuana remains illegal, and connected to far less medical concern. The notion of a conspiracy for profit to keep marijuana illegal while forwarding alternative, questionable and expensive drugs that would be unwanted with legal marijuana does influence his trust for these people.
On more solid ground, the notion that valid medicine might be overused to great long-term harm is also acceptable in the particular case of antibiotics - we’re seeing multiple antibiotic resistant strains outpacing our ability to find and dispense new antibiotics, and it is conceivable that other forms of medicine could set up selective pressures that limit their long-term viability. People who use antibiotics when it is completely unnecessary are driving the evolution of these new strains, so identifying cases in which a treatment is unnecessary (but not necessarily harmful in the short-term to that particular patient) is also important.
