What is Poliomyelitis?

Poliomyelitis, or commonly known as Polio, is a type of viral disease of the central nervous system. The causative agent is a non-enveloped, single-stranded RNA enterovirus and is a member of the Picornaviridae family. The main characteristic of this disease is the destruction of motor neurons which results in large muscle paralysis such as arms and legs. According to the review article published by Bangladesh Journal of Medicine, there are three serotypes of poliovirus and protection against one type does not provide protection to the two other types. The only reservoir are humans with a main mode of transmission being fecal/oral route. There are two types of polio vaccines available that are commonly used throughout the world, which are IPV and OPV. 

IPV, or inactivated polio vaccine, is a type of polio vaccine administered through an injection using the sterile syringe. OPV, or oral polio vaccine, is a type of polio vaccine consisting of an attenuated poliovirus. This can be administered orally, as drops on the tongue. Compared to the IPV, OPV is a more popular and convenient option because the cost of production is low, does not require syringes, and stimulates durable immunity, according to the research article posted on PLOS, a nonprofit journal publishing website. Moreover, the review article on the Bangladesh Journal of Medicine affirms that intestine is the primary site of the poliovirus entry and the strains in OPV produce effective immunity in the intestine as well as immunity to all three serotypes of the poliovirus. 

In the last six months, there hasn’t been a case of polio in the world. The PLOS research article states that number of incidences of polio cases has been reduced by more than 99.9% globally with wild polio virus occurrence only in three countries, Afghanistan, Nigeria, and Pakistan, since 2018. The use of polio vaccines since 1988 helped to significantly drop the number of cases in the world, which shows that vaccines have been effective. Although there are pros and cons to each type of vaccine, I believe that it has been efficacious in the effort to eradicate poliovirus because research shows that out of the three serotypes, type 2 and 3 has been eradicated. Even though type 1 virus is still prevailing in the three countries, some protection is better than no protection and I’m very impressed to know about the precipitous drop in the global cases as well as the effect of two polio vaccines.