1. 10 infectious diseases that could be the next pandemic | Gavi, the Vaccine Alliance (n.d.). https://www.gavi.org/vaccineswork/10-infectious-diseases-could-be-next-pandemic. Accessed 29 Nov 2021
2. 1957–1958 Pandemic (H2N2 virus) | Pandemic Influenza (Flu) | CDC (n.d.). https://www.cdc.gov/flu/pandemic-resources/1957-1958-pandemic.html. Accessed 22 Nov 2021
3. 1968 Pandemic (H3N2 virus) | Pandemic Influenza (Flu) | CDC (n.d.). https://www.cdc.gov/flu/pandemic-resources/1968-pandemic.html. Accessed 22 Nov 2021
4. A Timeline of HIV and AIDS | HIV.gov. n.d.. https://www.hiv.gov/hiv-basics/overview/history/hiv-and-aids-timeline. Accessed 22 Nov 2021
5. Abdool Karim SS, de Oliveira T (2021) New SARS-CoV-2 variants—clinical, public health, and vaccine implications. N Engl J Med 384(19):1866–1868. https://doi.org/10.1056/NEJMC2100362/SUPPL_FILE/NEJMC2100362_APPENDIX.PDF