The road leading to Hagadera in the Dadaab Refugee Complex is wide, straight and dusty.
Inside the camp, where tin and mud-walled houses are shielded from the wind by dry twig fences, the road narrows as it winds its way to the block E6 dispensary in the heart of the camp.
This is the first day of the round one vaccination campaign against polio in 12 high-risk counties, including Garissa.
The latest round targets children under five years, who will get the bivalent oral polio vaccine.
This morning, 29 teams, each comprising a team leader, a community health volunteer and a vaccinator, have been dispatched throughout the refugee camp.
According to Jamal Abdi, a community health promotion officer with the International Rescue Centre, the teams have one ambitious target; to immunise 35,000 children by the end of the campaign on Wednesday.
One of the teams is stationed at the block E6 dispensary, targeting children who are being taken there to seek various health services.
Across the fence from the dispensary is a dusty football field, where youths in bright uniforms are playing with an orange football donated by Unicef.
Dressed in brightly-coloured uniforms, the youths cheer robustly every time one of them scores a goal.
Although he would not mind playing, Awil Awad Abdoulle cannot join them because he is a polio survivor.
Supporting himself with walking aids, Awil ambles to a seat, not too far from the field, to share his story.
"I grew up in the rural parts of Kismayu," he says. When violence in his home country, Somalia, became too much for him to bear, he and a relative fled Somalia in the hope of finding Awil's sister, who was already sheltering at the Dadaab Refugee Camp. Awil was about 10 when he arrived at the camp.
"I came for peace and education," the Form Four student says in halting English. However, his dream did not have as a happy an ending as he had hoped.
In 2013, when he turned 19, he contracted polio, largely because he lacked immunity because he never had an opportunity to be immunised.
Because of the war in Somalia, children in that country routinely miss out on immunisation for the paralysing disease, leaving them vulnerable even in their teenage years, sometimes beyond.
"I woke up one day and I could not stand," Awil, the last person to be positively diagnosed with polio in Kenya, says.
His sister took him to the hospital in Hagadera market. Health workers sent his stool samples to a laboratory in Nairobi and confirmed that Awil had polio.
"I had hoped it could be cured," Awil, now a KCSE candidate at Al-Bushra Academy, says. "I thought that since the disease had a name, it must have a cure."
Before contracting the disease, Awil had heard about the disease but had never believed it could afflict anyone, until he got it. Now he supports immunisation campaigns, including in Block E of the Dadaab camp, where he lives.
In one homestead, the vaccination team finds Hodan Hassan Mohammed, a mother of three. Her youngest, who is about eight-months-old, was yet to be immunised.
After he is given the two drops of the Bivalent Polio Vaccine, he howls for a while but is intrigued into silence when indelible ink is used to mark his little, the one sign that his immunity has been boosted and his chances of leading a healthy and active life, like the boys in the football field, have been dramatically improved in that one act.
That means, if he comes into contact with a person carrying the polio virus, the probability that he, too, will be infected are significantly reduced.
Where it is not immediately possible to verify the age of a child, the immunisation team asks them to wrap the right hand around the top of their head and touch the opposite ear.
Those who can touch the ear are identified as above five years. Those who can't are then immunised.
According to Jamal Abdi, polio is a contagious disease that can be caused by poor hand-washing, poor hygiene or ingestion of faecal matter that has the polio virus.
Dadaab is particularly vulnerable because of the weak soil structure that causes latrines to collapse.
And because the area is arid, water is scarce, making the community vulnerable to sanitation diseases such as cholera and polio.
Dadaab is about 100 kilometres from Kenya's border with Somalia, where seven polio cases have been isolated this year alone.
Movement across the porous border makes the population at the refugee camp particularly vulnerable because some of the refugee have regular contact with their relatives or acquaintances from Somalia.
There is also regular contact between the refugee population and Eastleigh, Nairobi, where health surveillance experts identified the polio virus within the sewage system, making it necessary to carry out the vaccination there as well. However, no case of polio transmission has been reported in Kenya.
According to Dr Peter Okoth, a health specialist with Unicef, every unimmunised child puts every child in Kenya at risk of contracting polio.
This is why other counties, such as those that neighbour Nairobi and Garissa, have been included in the ongoing campaign.
Previous campaigns have aimed at eradicating polio from Kenya.
However, cognisant that Kenya's borders are porous and neighbouring countries such as war-ravaged Somalia are yet to eradicate the disease, it has become necessary to embark on a more ambitious target.
According to Dr Orkhan Nasibov, the senior public health officer with UNHCR in Dadaab, the aim now is to kick polio out of the Horn of Africa.
"We want the region to be clean of polio," he says.