What are IPV/OPV?


OPV is an abbreviation for oral polio vaccine and as the name suggests it is a vaccination against polio taken orally. Polio is caused by the poliovirus, a disease that leads to complications such as paralysis in the more severe situations. Of late, through proper vaccination, episodes of natural polio virus infections are very rare but the disease is still common in some parts of the world. There are three types of poliovirus, all of which are contained in both the vaccines. The virus is only found in people, in their throats and intestines. For example an infected person will have the virus in their stool. Polio can be passed on to others through infected fluids from stool or respiratory secretions. The virus attacks the brain and spinal cord; symptoms include fever, sore throat, vomiting and in some situations other complications such as weak muscles, joint pain (leading to paralysis), can arise.

In the majority of the cases, there are no obvious symptoms while in the remaining small percentage of individuals, the infection can be severe enough to cause paralysis of the legs mostly, but polio can also affect other muscles. Polio is virtually non-existent in some parts of the world e.g. the United States, therefore the IPV shot or inactivated polio vaccine is used. This has the killed virus from the three groups of poliovirus. IPV is designed such that it will trigger the antibody response without causing the disease. OPV is not used in very young babies simply because it can cause VAPP (vaccine-associated paralytic polio) and to avoid such scenarios, only IPV is used in some countries. IPV is administered at 2 and 4 months while 2 shots of OPV are given during the balance period; both vaccines contain the three viruses in weakened live forms. Both vaccines are effective but OPV is believed to be better at containing the spread of the disease and providing 'herd immunity' in unvaccinated people. The downside is that it is also known to cause VAPP in very, very small percentages (those with weak immunity systems are especially susceptible). IPV on the other hand has no side effects other than the occasional swelling at the site of the shot. These vaccines can prevent polio and since polio still exists in the world it is important to continue immunization against it.

Doses: Vaccines in use IPOL (Inactivated IPV), Pediarix (IPV, DTap and HBV vaccines). Both the shot and syrup are given at 2, 4, 6-18 months and the last one at 4-6 years of age.