"COVID-19 situation report for WHO Africa Region"(PDF). NIHR global health research unit tackling infections to benefit Africa at the University of Edinburgh. 30 September 2021. p. 27. Retrieved 11 October 2021.
"COVID-19 situation report for WHO Africa Region"(PDF). NIHR global health research unit tackling infections to benefit Africa at the University of Edinburgh. 2 December 2021. p. 27. Retrieved 7 December 2021.