Is it true that 25% of those with Covid-19 in Nigeria have no travel history or known contact with infected persons?
The percentage has varied over time. On 3 June, the Nigeria Centre for Disease Control (NCDC) reported that 75% of Covid-19 cases in Nigeria had unknown sources of infection; 2% had a travel history and 23% were contacts of existing patients. “It means that community transmission is happening. It means that you cannot link your exposure to one particular person or one event,” said the centre’s director-general, Dr Chikwe Ihekweazu. He said this was to be expected in the case of a respiratory virus with a large share of people who don’t show symptoms.