IMMUNISATION WEEK: Everything you need to know about polio vaccine

Polio mutates in the body of a vaccinated child and is then passed on through their faeces.

Polio mutates in the body of a vaccinated child and is then passed on through their faeces.

Photo credit: shutterstock

What you need to know:

  • Poliomyelitis or polio is a virus that can cause paralysis and largely affects children under the age of 5 years.
  • The poliovirus is transmitted through contaminated contact with an infected person, contaminated food, or water.
  • Kenya has not reported any cases of wild polio (WPV1) since 2014.


Vaccination against polio disease is one of the most widely known vaccination campaigns in Kenya. Every now and then, the Ministry of Health carries out polio vaccination campaigns that target children who have not been vaccinated.

What is polio?

Poliomyelitis or polio is a virus that can cause paralysis and largely affects children under the age of 5 years. “This disease is considered life-threatening. The poliovirus is transmitted through contaminated contact with an infected person, contaminated food or water,” states the WHO. This virus mutates in the body of a vaccinated child and is then passed on through their faeces. This mutated virus can cause paralysis if it infects another child who has not been vaccinated. According to the WHO, polio can be easily imported into a polio-free country and spread rapidly among under-immunized populations. One in 200 infections leads to irreversible paralysis, 5-10 percent of whom die when their breathing muscles become immobilised.

Transmission

Kenya has not reported any cases of wild polio (WPV1) since 2014. As of 2021, this type of polio was eradicated worldwide in all but two countries, Pakistan and Afghanistan. However, two circulating vaccine-derived poliovirus type 2 (cVDPV2) positive environmental samples were reported, one in 2020 and another in 2021. The viruses were linked to the Banadir outbreak in Somalia. These viruses, which were reported in Garissa and Mombasa are a form of the poliovirus that occurs in under-immunised communities with poor sanitation. In May 2021, the Ministry of Health in partnership with UNICEF and the World Health Organization (WHO) set out to immunise three million children across 13 counties after the poliovirus was confirmed to be circulating in Garissa and Mombasa. The targeted areas included Garissa, Isiolo, Kajiado, Kiambu, Kilifi, Kitui, Lamu, Machakos, Mandera, Mombasa, Nairobi, Tana River, and Wajir counties, as well as in the Dadaab refugee camps.

Symptoms

According to the Centre for Disease Control, about 7 out of every 10 who get infected with the poliovirus will not have any visible symptoms. “About 1 out of 4 people with poliovirus infection will have flu-like symptoms,” states the CDC. These symptoms may include sore throat, nausea, headaches, fever, fatigue, and abdominal pain. These symptoms will usually last for 2 to 5 days, then go away on their own. Where severe symptoms are experienced, the CDC states that someone with this virus may suffer from symptoms that could affect their nervous system. “These include paresthesia which is the feeling of pins and needles in the legs, meningitis which is the infection of the covering of the spinal cord and, or brain, and paralysis,” states the CDC.

Out of these three symptoms, paralysis is the most severe outcome. It is also the most common cause of permanent disability and polio-related deaths. “Between 2 and 10 out of 100 people who have paralysis from poliovirus infection die, because the virus affects the muscles that help them breathe,” the CDC states.

Complications

Although it is possible for polio to be managed and treated if detected in a child early, the CDC cautions that having your baby exposed to this virus could lead to health problems in the child’s later years. “The child can seem to fully recover from this virus, but they may develop post-polio syndrome fifteen to forty years later. Post-polio syndrome is characterised by muscle pain, weakness, or paralysis,” says the CDC.

Immunisation

Immunisation is the best form of defense against the polio virus. Outside of immunisation, there is no cure for polio. According to the Kenya Expanded Programme Immunisation Schedule, this immunisation should start soon after your baby is born. Oral poliovirus vaccine (OPV) is the most common method of polio immunisation in Kenya. With this method, children receive doses of the vaccine by drops in the mouth. There is also the Inactivated poliovirus vaccine (IPV) which is administered in some countries such as the United States. This method is administered through an injection. Your baby will normally receive their polio vaccine at weeks 6, 10, and 14 after birth. At this stage, your newborn will receive the oral polio vaccine in two drops orally. The first dose is known as the birth dose and is administered at birth or within the first two weeks. This vaccine is meant to prevent poliomyelitis (polio). During vaccination, three doses of live-attenuated oral polio vaccine produce protective antibodies to all three poliovirus types in more than 95 percent of children who are immunised. Besides the oral polio vaccine, there is the inactivated polio vaccine which is given by injection with dosage depending on the baby’s age. “Almost all children who get all the recommended doses of polio vaccine will be protected from polio,” the CDC states.