What is the likely scenario after the second wave of Covid 19
By Louis Torronde , December 2 2020
The end of the year 2020 is characterized by a decrease in the number of cases of contamination in Europe following the containment measures taken by the various countries. But the announced end of the 2nd wave is not true everywhere, particularly in the United States. This country is facing a very virulent wave of contamination fueled by the lack of coordinated measures at the federal level and the evolution of the pandemic would rather suggest that it is a powerful 2nd wave and not a 3rd wave, the 1st wave having never really decreased since April.
This situation at the end of 2020 questions retrospectively the probabilities presented in the spring on the evolution of the pandemic and allows us to build hypotheses on how the pandemic will evolve in the coming months. Retrospectively, the evolution of the epidemic as it currently stands was already identified in May by taking as a comparison the profile of other epidemics. Above all, the scenario of a larger wave in the fall was preferred by some scientific experts. However, these calculations do not foresee a 3rd wave larger than the 2nd, but rather a succession of small waves.
At the same time, several hypotheses are being considered to anticipate the future evolution of the virus. The least probable hypotheses are those that envisage either a natural extinction of the virus as for SARS in 2003, or a collective immunity, since the worldwide spread of the virus, the non-seasonal nature of Covid-19, the cases of re-infection or the absence of data on the duration of immunity once the virus is contracted do not allow validation of these two hypotheses. Another unlikely hypothesis is that of a vaccine that would permanently stop the circulation of the virus because, as historian Nükhet Varlik of the University of South Carolina points out, only the smallpox vaccine has been able to permanently eradicate a virus. In most cases, vaccines work by reducing the number of infected and dead people, but they must be renewed regularly, for example, every year. This is therefore a hypothesis envisaged for Covid-19, a virus that returns in cycles and whose spread would be slowed down by a vaccine, while maintaining measures to protect populations to limit its circulation, as is the case for Ebola or influenza in particular.
For example, a vaccine to be marketed in 2021 will control the current strain of Covid-19, but it is not certain that it will be adapted to future mutations in the virus, as has already been seen in mink in several countries such as Denmark, the Netherlands and Ireland.
At a time when the mode of transmission of the virus from animals to humans is not yet completely known, these developments are being monitored by scientists because certain mutations could allow the virus to be transmitted more easily from one human being to another.
These mutations and their impact on the dangerousness of the virus to humans are also closely monitored by political authorities because these observations allow governments to adapt protective measures for populations, health care systems and the types of vaccines to be used. In France, for example, the French Senate commissioned a study in 2010 on the H1N1 virus, the conclusions of which recommend, among other things, improving national and European coordination between surveillance networks, setting up a Task Force in charge of communication, and defining proportionate and graduated pandemic plans. This study is still relevant 10 years later for the Covid-19 pandemic.
In this context, the evolution of the pandemic in the different countries attests to the usefulness of the measures taken by governments as these interventions influence the number of contaminations and deaths caused by the successive waves. Governments are adapting their decisions according to the context, while waiting for the distribution of a vaccine and appropriate treatments. In order to do this, the authorities' knowledge of the places most likely to spread the virus is a major challenge in setting up targeted or general containment and organizing the opening and closing of certain activities according to their impact on the spread of the virus. A study published in Nature magazine in November 2020 indicates that restaurants, hotels, sports halls and religious establishments are the main places at risk, and it is easy to understand that the waves of contamination decrease when measures are taken to close these establishments and increase when the use of these places is allowed again if personal protective measures are not put in place or respected.
As knowledge of the virus improves, scientists are already considering the need to periodically update the Covid-19 vaccine to take into account possible new virus strains. In this case, vaccines remain a bet on which strain will be effective in the coming season, as was the case in 2016 for example for the influenza vaccine effective at only 30%. This perspective explains why WHO, in particular, considers a vaccine successful when it is more than 50% effective and why the Food and Drug Administration could authorize, in the case of Covid-19, any vaccine with more than 50% effectiveness.
This discovery contributes to the improvement of knowledge on the mutation capacities of the virus. However, at present, there is only partial data on the category of Covid-19, an RNA virus. Scientists are already certain that RNA viruses are not stable and mutate rapidly. However, at the same time, some of the cells have the ability to correct errors when the virus copies itself, which would mean that the virus would eventually mutate only slightly, and more importantly, it would mutate half as fast as the flu virus. In addition, since studies of virus mutation conclude that mutations attenuate the virulence of the virus, it is possible to hope that Covid-19 behaves similarly.