Kenya has detected at least three cases of the new Omicron variant first detected in South Africa last month.
Health CS Mutahi Kagwe on Wednesday said the cases were detected among travellers.
Last week, Uganda announced it had detected cases of the Omicron Covid-19 variant in travellers coming into the country, the first infections to be reported in East Africa.
The cases were detected in people screened at Entebbe International Airport who flew in from five different countries, Ugandan medical authorities said in a statement.
Five had come from Nigeria, two from South Africa -- where the variant was first reported -- and two from the United Arab Emirates.
On Tuesday, results of a study published in South Africa showed two shots of Pfizer's Covid vaccine offers around 70 percent protection against severe disease from Omicron.
The emergence of the highly mutated variant sparked fears that it could cause severe disease, be more contagious or could evade vaccines.
Early indicators suggest that it could be more transmissible, but promising data so far has suggested that vaccines still offer protection against Omicron.
The latest research out of South Africa suggested that two doses of the Pfizer/BioNTech vaccine still offered protection against serious illness.
"The double dose of Pfizer/BioNTech vaccine showing 70 percent effectiveness in reducing risk of hospitalisation," said Ryan Noach, the head of South Africa's leading private health insurance company, Discovery, which co-led the study.
Two doses of the vaccine offered 93 percent protection against earlier variants, according to the companies.
The study was based on the results of 78,000 PCR tests taken in South Africa between November 15 and December 7 and was conducted by Discovery along with the South African Medical Research Council (SAMRC).
"We are extremely encouraged by the results," said SAMRC head Glenda Gray.
But Noach warned that despite the protection offered by two doses, hospitals could still be overrun since Omicron is spreading rapidly in South Africa.