Written By Polio, a viral disease that can cause paralysis, has been one of the most devastating diseases of the 20th century. Thanks to the development of polio vaccines, the disease is now close to being eradicated. But how do these vaccines work, and why are they so important?
Polio vaccines work by stimulating the body’s immune system to produce antibodies against the poliovirus. There are two types of polio vaccines: inactivated polio vaccine (IPV) and oral polio vaccine (OPV).
IPV, also known as the Salk vaccine, is made from a killed form of the poliovirus. When the vaccine is injected into the body, the immune system recognizes the virus as foreign and produces antibodies against it. If the person is later exposed to the live poliovirus, their immune system will recognize it and be able to fight it off. IPV is usually given in a series of four doses, starting at two months of age.
OPV, also known as the Sabin vaccine, is a live, weakened form of the poliovirus. When the vaccine is given orally, the weakened virus replicates in the intestines, stimulating the immune system to produce antibodies. Like IPV, if the person is later exposed to the live poliovirus, their immune system will be able to fight it off. OPV is usually given in a series of four doses, starting at six weeks of age.
Both IPV and OPV have been successful in reducing the incidence of polio. However, there are some differences between the two vaccines. While OPV is more effective at inducing immunity in the intestines, it carries a small risk of causing vaccine-associated paralytic polio (VAPP). IPV, on the other hand, does not carry this risk, but is more expensive and requires injection.
Polio vaccines have been critical in the fight against polio. According to the World Health Organization (WHO), since the introduction of polio vaccines in the 1950s, the number of polio cases worldwide has decreased by over 99%. The last remaining endemic countries are Afghanistan and Pakistan, where the poliovirus still circulates. Efforts to eradicate polio in these countries are ongoing, with a particular focus on ensuring that all children receive the polio vaccine.
The importance of polio vaccines extends beyond the prevention of the disease itself. Vaccination also contributes to the concept of herd immunity, where a significant portion of the population is immunized against a disease, thereby reducing the risk of transmission to vulnerable individuals who cannot receive the vaccine, such as those with weakened immune systems.
Despite the effectiveness of polio vaccines, there are still challenges to overcome. In addition to the ongoing effort to eradicate polio in Afghanistan and Pakistan, there are concerns about vaccine hesitancy and misinformation. It is important to continue educating the public about the safety and efficacy of polio vaccines, and to ensure that all children receive the vaccine as part of routine immunization schedules.
In conclusion, polio vaccines have been a major success story in public health. The science behind these vaccines is complex, but their impact has been profound. As we work towards the eradication of polio, it is important to continue supporting vaccination efforts and educating the public about the importance of vaccines in preventing disease.
