Roundworm are very deep seeded and tenatious in the body. I see too many reports of people who say they got rid of some and then move on to conquer their other issues, all the while they probably still have the worms expelling viruses and pathogens into their bodies.
It's can take up to a full year of "whatever" gets bunches out for you. Constant cleansing, switching it up. There are never just a few.