medical experts in the uk are warning that a device designed to help spot early signs of dangerous falls in oxygen levels in patients with respiratory conditions works less well for people with darker skin tones. nhs england and the medicines regulator, the mhra, say pulse oximeters can over estimate the amount of oxygen being taken in. more than a00,000 covid 19 vaccines are due to arrive in kenya as part of a surplus the uk government is donating to poorer nations. the british foreign secretary has called on other countries to also donate vaccines to assist vulnerable nations dealing with fresh waves of coronavirus. bbc s rhoda odhiambo in nairobi has more on covid vaccinations in kenya. so, right now more than a million people have been vaccinated, but if you look at the people who have received two doses of the oxford astrazeneca vaccine, which is currently being used