Your illness won't have any affect on your health insurance costs. You'll continue to pay the same price as everyone else on your particular plan.
If you need to get any treatment, it's always a good idea to give VHI a call beforehand to check that you're covered. It won't make any difference to how your claim is paid, so there's no problem if you don't call them, but it gives you a chance to doublecheck everything and avoid any surprises.