A pandemic respiratory disease is one of the scariest diseases due to its rapid spread among immunologically naïve humans and due to the fact that there is no vaccine against a new virus strain with a zoonotic origin. In the past two decades, there have been several outbreaks of zoonotic origin in human populations including the chikungunya outbreak in Caribbean countries and South America in 2013–2014 [1], Zika outbreak in the Americas in 2015–2016 [2], Ebola outbreak in 2014–2016 in West Africa [3], HPAI and LPAI outbreaks several times in many countries including Egypt, China, Indonesia, Canada and Australia [4,5], SARS-CoV outbreak in 2002–2004 in 26 countries [6,7], and MERS-CoV outbreak since 2012 in 27 countries [8]. However, a pandemic had not occurred until airborne viruses, including a quadruplex influenza A (H1N1) virus of swine origin and SARS-CoV-2 [9], emerged. The new H1N1 virus caused the 2009 influenza pandemic in June 2009 [10]. SARS-CoV-2, which causes COrona VIrus Disease 2019 (COVID-19), became the first recorded coronavirus pandemic on 11 March 2020 [11]. There are various influenza viruses (IVs) and various coronaviruses (CoVs), which are grouped into 4 genera, alpha, beta, gamma and delta IVs/CoVs (Table 1 and Table 2).