The mass vaccination campaign comes as a new invasive species of mosquito has been found in Kenya that scientists fear could reverse gains against the disease.
Health officials say malaria kills more than 12,000 Kenyans each year and more than half a million people in sub-Saharan Africa, most of them children.
Diana Kavwai, a mother of two, recounted the day in 2019 when her 1-year-old son became sick. Kavwai said she tried home remedies to ease his fever, but he succumbed to malaria.
"His body was very hot and he was shaking," she said. "When we went to the hospital, examination showed that he had malaria, but it was too late.''
Kavwai said she believes that the recent vaccination campaign for children under the age of two will help to protect them from the disease, especially during rainy seasons.
Kenya's government aims to vaccinate at least 300,000 children annually against malaria in a new initiative, particularly in the eight malaria-prone regions.
Pharmacist Lucy Mecca, who heads immunization programs, said the vaccine, which was piloted in Kenya, Malawi and Ghana in 2019, has proven effective.
"The prevalence of malaria is going down nationally to about 6%; even in these lake-endemic zones, we can see that it has gone down from 27% to 19% and that the interventions that have been put in place for malaria are actually working," Mecca said.
Despite the progress, authorities say a new mosquito vector, Anopheles Stephensi, that Kenyan scientists recently detected in the country is threatening gains made in the fight against malaria.
The carrier, which was known to be in southeastern Asia, the Middle East and Arabian Peninsula, has the ability to thrive in urban areas and can breed in man-made containers. Kenya is closely monitoring its extent, as Mecca explains.
''The malaria program is looking into that; they are concerned about it so that they are able to see if there are any interventions that need to be done above the current interventions. But as per the advice, we continue with the current interventions that have been put in place for all the areas that are zoned out in the country," Mecca said.
In a 2022 report, the World Health Organization warned of a surge in mosquito-borne diseases due to global warming, which is increasing vector survival and biting rates. The WHO technical officer for malaria vaccines in Kenya, Adam Haji, told VOA that finding new ways to combat the disease is key.
''There is a need and there is a requirement for the world to have new tools in order to put us back on track and the malaria vaccine is one of these new tools," Haji said.
Malaria interventions in Kenya have included distribution of mosquito nets, spraying and minimizing potential breeding grounds. Health authorities say they hope that vaccination initiatives will help to eradicate the disease.