1. Listings of WHO’s response to COVID-19. Available: https://www.who.int/news/item/29-06-2020-covidtimeline [Accessed 16 January 2021].
2. Analytical report of the first, second and third wave studies, 2020. Available: https://www.unicef.org/georgia/media/4736/file/COVID-19-Study-Analytical-Report-1-st-2nd-and-3rd-waves-Eng.pdf#page=12&zoom=100,92,96
3. NICD . COVID-19 second wave in South Africa, 2020. Available: https://www.nicd.ac.za/covid-19-second-wave-in-south-africa/ [Accessed 16 January 2021].
4. A new strain of coronavirus: what you should know | Johns Hopkins medicine. Available: https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/a-new-strain-of-coronavirus-what-you-should-know [Accessed 16 January 2021].
5. Developing Covid-19 vaccines at pandemic speed;Lurie;N Engl J Med,2020