The combination hepatitis A and B vaccine (Twinrix) is administered at which of the following monthly intervals?

The correct administration schedule for the combination hepatitis A and B vaccine (Twinrix) is 0, 1, and 6 months. This means that the first dose is given initially (0 months), the second dose is given one month later (at 1 month), and the third dose is administered six months after the first dose (at 6 months). This schedule is designed to provide optimal immunity against both hepatitis A and hepatitis B, ensuring that individuals receive the complete course of vaccination with adequate spacing between doses for maximum effectiveness.

The choice of another schedule would not provide the same level of protection as it is critical for the timing of immunizations to follow the established guidelines to ensure that the immune response to both viruses is effective.