The Zika virus has been circulating in Kenya for decades, without causing the devastating birth defects seen in Latin America South America and the United States, researchers say.
The virus can cause babies to be born with under-developed brains and abnormally small heads, the most feared outcome of infection during pregnancy.
Children can develop epilepsy, cerebral palsy, learning disabilities, hearing loss and vision problems. In some cases, they develop normally.
The virus does not appear to have caused the same problems in Kenya.
The disease is transmitted by mosquitoes and can be passed from a pregnant woman to her foetus. The pregnant woman herself and most adults are not seriously affected.
Kenya was untouched by the 2016 global outbreak, but some samples of stored blood from Kisumu, Eldoret, Nairobi, Kilifi and Mombasa contain the virus antibodies.
In 2016, the WHO declared the Zika virus a global public health emergency after an outbreak largely in South America and the US.
The infection caused thousands of babies to be born with microcephaly or an abnormally small head, because their brains did not developed properly.
Microcephaly is common at the Coast but the Kenya Medical Research Institute scientists say it is not linked to Zika.
Last year, the scientists assessed data from 11,061 live births at Kilifi County Hospital between January 2012 and October 2016, and found one to two per cent of the babies had microcephaly.
In comparison, the overall microcephaly prevalence in Brazil during the 2016 outbreak was estimated at 0.15 per cent, almost 10 times lower than Kilifi.
The Kemri scientists said they carried out all tests on the Kenyan babies, and are confident their microcephaly was not caused by Zika.
"We undertook detailed serological testing in cases and controls and did not find any Zika virus or flavivirus RNA," they said, in the study published by Wellcome Research in November last year.
(Edited by V. Graham)
