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The world may be focused on COVID-19, but health officials and countries are looking ahead to the current 2020-2021 influenza season in order to anticipate demand on health systems in context of the COVID-19 pandemic. [1] With more than 211,000 COVID-19 related deaths, the US could see a resurgence of disease later this year in combination with seasonal influenza. [2] While the 2018-2019 influenza season in the US was of moderate severity it resulted in 35.5 million influenza cases, 16.5 million medical visits and 490,000 hospitalizations. [3] Joint occurrences of COVID-19 and the seasonal influenza this fall and winter could result in considerable morbidity and mortality.
Forecasts for the Northern Hemisphere influenza season are often predicted from data collected during the ongoing Southern Hemisphere influenza season, including selection criteria for virus strains included in the seasonal influenza vaccine. [4] [5]. However, countries in the Southern Hemisphere are reporting lower numbers of flu cases in comparison to previous years. [6]
South Africa’s National Institute for Communicable Diseases reported that the 2020 influenza season has shown a significant reduction in the number of cases. [7] Australia having a severe influenza season in 2018-2019 reported 30,567 cases but only 171 in May 2020. [8] Similarly, the Ministry of Health of Brazil reported only 199 registered fatalities from influenza on June 3rd, 2019. [9]
The unexpectedly low reported influenza incidence is encouraging yet concerning. Health officials have partially attributed the decline of influenza cases to widespread coronavirus restrictions such as travel restrictions, personal PPE, and social distancing. [10] In contrast, low incidence could also be attributable to a result from insufficient testing and diminished resources due to focus on the COVID-19 pandemic. [11] Nevertheless, the interactions between COVID-19 and seasonal influenza have shown uncertainty of the 2020-2021 influenza season making it difficult to develop forecasts and preparations.
References
[1] https://time.com/5860066/coronavirus-flu-cdc-director/
[2] https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm
[3] https://www.cdc.gov/flu/about/burden/index.html
[4] https://www.who.int/influenza/gisrs_laboratory/flunet/charts/en/
[5] https://www.cdc.gov/mmwr/volumes/68/wr/mm6840a3.htm
[6] https://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/
[7] https://www.nicd.ac.za/wp-content/uploads/2020/05/Weekly-Respiratory-Pathogens-Report-Final-pdf.pdf
[8] http://www9.health.gov.au/cda/source/cda-index.cf
[9] https://riotimesonline.com/brazil-news/brazil/influenza-deaths-in-brazil-account-for-199-cases/
