It is noted that the Federal Drug Administration of USA has granted a conditional approval to the anti-viral medication Remdesivir 20. In this direction unprecedented efforts are underway. The second optimal solution would be the discovery of effective pharmacological interventions. During the pandemic's first wave, such a vaccine was not yet available. Naturally, the best possible scenario of minimizing the possible impact of lifting the lockdown measures and to prevent new waves would be the availability of a safe and effective vaccine. Furthermore, such features are expected to worsen, especially due to the effect of the post-traumatic disorder. Indeed, the psychological impact on the population at large of the imposed restrictions was substantial 19. This was considered vital, not only for economical but also for health considerations. The importance of easing the lockdown measures differently, depending on the age of individuals, is argued in 18. These papers are only indicative examples of an ever-expanding volume of literature of well over 5000 papers within the first few months of the pandemic alone, in arXiv, medRxiv and bioRxiv.įollowing the expected decline in several European countries of the ‘first wave’ of infections, the lockdown measures began to be lifted in May.
These models aim to capture the epidemics of different countries 8, 9, 10, 11, or states as well as provinces 12, 13, 14, 15, 16, 17. In addition to these works, a great variety of models have appeared in the literature stemming from deterministic, as well as probabilistic variations of the broad SIR class of models. Similar results regarding reported infections were presented in 7). Remarkably accurate predictions for the time that a plateau would be attained (defined as the time when the rate of deaths is 5% of the maximum rate) as well as the corresponding number of total deaths at that time, were presented, e.g., in 6. For the above countries, the curve depicting the number of deaths as a function of time also passed the inflection point. As a result of these measures, the curves depicting the total persons infected by SARS-CoV-2, in China, South Korea, many European countries, USA, and several other countries, passed by April 2020 the inflection point, namely the point where the rate of infected individuals reached its maximum. In order to combat this threat, during the pandemic's first wave several countries used justifiably draconian measures which culminated in a complete lockdown. As a result of this high transmissivity, as well as of the delay of the international community to take appropriate preventive measures, SARS-CoV-2 has caused a pandemic, which represents the most serious global public health threat since the devastating 1918 H1N1 influenza pandemic that killed approximately 50 million people (in proportion to today’s population, this would correspond to about 200 million people). Perhaps the increased transmissivity of SARS-CoV-2 is due to its dual receptor attachment in the host cells: it has been shown that the attachment of SARS-CoV-2 to the surface of respiratory cells is mediated by certain viral proteins which bind not only to the angiotensin converting enzyme-2 (ACE-2) receptor 3, but also bind to sialic acid containing glycoproteins and gangliosides that reside on cell surfaces 4 (this is to be contrasted with SARS-CoV that binds only to ACE-2 receptors 3, 4, 5). However, SARS-CoV-2 is highly contagious. Fortunately, it has lower mortality rates than these two viruses which caused outbreaks in 20 2. SARS-CoV-2, the causative virus of the current pandemic, has 75–80% identical viral genome sequence with the coronaviruses (MERS)-CoV and SARS-CoV 1.