1. Center for Disease Control and Prevention. Flu Season. CDC; 2021. Available from: https://www.cdc.gov/flu/about/season/flu-season.htm.
2. Influenza's Unprecedented Low Profile During COVID-19 Pandemic Leaves Experts Wondering What This Flu Season Has in Store;Rubin;JAMA,2021
3. World Health Organization. Global Influenza Surveillance and Response System (GISRS). WHO; 2021. Available from: https://www.who.int/initiatives/global-influenza-surveillance-and-response-system.
4. World Health Organization. WHO Consultation on the Composition of Influenza Virus Vaccines for Use in the 2022 Southern Hemisphere Influenza Season. WHO; 2021. Available from: https://www.who.int/news-room/events/detail/2021/09/13/default-calendar/who-e-consultation-on-the-composition-of-influenza-virus-vaccines-for-use-in-the-2022-southern-hemisphere-influenza-season.
5. World Health Organization. Recommended composition of influenza virus vaccines for use in the southern hemisphere 2022 influenza season and development of candidate vaccine viruses for pandemic preparedness. WHO; 2021. Available from: https://cdn.who.int/media/docs/default-source/influenza/who-influenza-recommendations/vcm-southern-hemisphere-recommendation-2022/202109_qanda_recommendation.pdf?sfvrsn=b9faa1cf_12.