Q: My son is 5 years old. His DPT vaccination booster dose is due. Which brand vaccine should I purchase? His doctor is not in town & friends have given different opinions. Someone told me that he bought the DPT vaccination from a hospital & paid only Rs. 200. Another person said that they paid Rs. 1,000 for the same vaccination. Why is there so much price difference for the same vaccine in the same town?

A:There are two basic types of DPT vaccines: (i) Conventional cellular pertussis component one, which is cheaper (ii) Newer acellular pertussis component one, which is the expensive one that you refer to. Both types of vaccine offer equal protection against the three doses. However, the chances of side effects, namely pain, swelling, and redness at the local site and fever are higher with the cellular (cheaper) vaccine (about 30-35% chance); with acellular (expensive vaccine) chances of these side effects are below 3-4%. Thus you should decide if you want to opt for the expensive vaccine to lower the chances of side effects by 25%. If the earlier DPT vaccination was the cheaper one and there were no side effects mentioned above, you can safely opt for the cheaper vaccine.