•The vaccination campaign targets 13 counties and more than 3.4 million children younger than age five.
• In October, 11 counties were flagged as having the greatest risk of an outbreak of vaccine-derived polio.
Image: MAGDALINE SAYA
Kenya will vaccinate more than 3.4 million children against polio in 13 counties from May 22 to 26.
The children are aged five and younger.
The counties are Nairobi, Machakos, Kiambu, Mombasa, Garissa, Mandera, Isiolo, Wajir, Kitui, Tana River, Lamu, Kilifi and Kajiado.
The campaign aims to vaccinate 249,391 children in Garissa, 255,885 in Mandera, 51,206 in Isiolo, 180,714 in Wajir, 175,425 in Kitui, 85,020 in Tana River, 25,104 in Lamu, 233,770 in Machakos, 330,465 in Kiambu, 327,338 in Kilifi, 234,197 in Kajiado, 965,243 in Nairobi and 323,620in Mombasa.
“In the last 12 months, we have had no case of polio but we do have circulating derived poliovirus. It looks like we are making progress,” Dr Richard Banda said.
Dr Banda is a public health expert, technical officer for the Expanded Programme on Immunisation of WHO and liaison officer at the World Health Organization.
"The only time a single case of the circulating virus was not reported, was between October and December 2018. Then we started having so many cases and we reached the peak at around July. Fortunately, in the past five months all the cases are basically going down,” Dr Banda said.
In October last year, 11 counties were flagged as having the greatest risk of outbreak of vaccine-derived polio.
Specialists said there is a build-up of thousands of under-immunised children in these regions. The situation is further compounded by Covid-19 in areas where immunisation levels were low.
Based on risk analysis, Mombasa, Nairobi, Lamu, Tana River, Garissa, Wajir, Marsabit, Killifi, Turkana, Isiolo and Mandera were put on alert.
"Out of a total of six viruses detected in the two counties, four are in Garissa. Three of them were picked from healthy children crossing the border from Somalia to Garissa while one was picked from a Garissa environmental site." the expert said.
The two viruses from Mombasa were picked from the Mombasa Golf Club environmental site, Banda said
Kenya last reported the vaccine-derived poliovirus in April 2018, when Kenya Medical Research Institute scientists found live polioviruses in sewage samples from Eastleigh estate in Nairobi.
Occasionally, if a population is seriously under-immunised, an excreted vaccine-virus can continue to circulate for an extended period of time. The longer it survives, the more it undergoes genetic changes.
The vaccine-virus can genetically change into a form that can paralyse – this is what is known as a circulating vaccine-derived poliovirus (cVDPV).
The continent was declared free from all the three strains of wild poliovirus in 2020 but the Eastern Mediterranean Region is yet to be certified.
The wild poliovirus occurs naturally in three strains – type 1, type 2 and type 3.
Type 2 was declared eradicated globally in 2015, and type 3 in 2019. Only type 1 remains in Afghanistan and Pakistan.
Polio is a serious infectious illness caused by the poliovirus. It is spread through contact with the stool of an infected person.
Symptoms include fever, tiredness, headache, vomiting, stiff neck and pain in the arms and legs.
For one in 200 people with a polio infection, the virus travels to the nervous system causing permanent paralysis, usually in the legs. This is called paralytic polio.
(Edited by B. Makokha)