WINDHOEK, Dec 6 (Reuters) - Namibia has detected the Omicron coronavirus variant in 18 of 19 samples sequenced between Nov. 11-26, its health ministry said on Monday. Although the southern African country has sequenced relatively few samples, the finding suggests the variant first flagged by neighbouring South Africa and Botswana late last month, and since labelled "of concern" by the World Health Organization, is also highly prevalent in Namibia. Namibia"s Omicron cases were detected predominantly in and around the capital Windhoek, a region that recorded 536 out of 695 new infections countrywide in the first five days of December. The other non-Omicron sample sequenced among the 19 was the Delta strain. Scientists in South Africa and other countries are racing to establish whether or not Omicron is more contagious, causes more severe disease and is more resistant to existing vaccines. "We must remain on guard while we wait for further investigation about this variant," Namibia"s health ministry said in a statement. Namibia had been on high alert for Omicron after it was identified in two people in Japan and the Czech Republic who had a history of travel to Namibia. Namibia, which has fully vaccinated only around 318,000 people in its 2.5 million population, warned last month that over 268,000 doses of AstraZeneca (AZN.L) and Pfizer (PFE.N) COVID-19 vaccines were at risk of being destroyed due to slow uptake. read more