The road is still long, but it could be downhill. The main hypotheses on the future and on coexistence with SARS-CoV-2 and the unknown mutations
The cold season is upon us and they have passed almost two years since the start of the Covid-19 pandemic. To date, the coronavirus has infected more than 240 million people and nearly 4.9 million have died. What is the path that the virus has taken? We can predict come cambier in the next future?
The transformations of the virus
The latest hypotheses on the subject of epidemiology suppose a long (and hopefully quite peaceful) coexistence with SARS-CoV-2, but the unknowns are more than certainties, because this virus does not quite resemble the 4 coronaviruses still circulating nor the flu we face every winter. You don’t get out of a pandemic in a week – you need one phase of tran
sition that could take place just this winter and that it would bring from a pandemic to an endemic (when a contagious disease is constantly present, but whose annual number of cases is not subject to large variations). The scenarios depend on the numerous factors at play and how they will evolve; one of these concerns coronavirus mutations.
Delta variants and subtypes
In much of the world, infections remain uncontrolled and this gives the virus more possibility of evolution
: it could become more transmissible, be able to evade the defenses of the immune system or be more virulent, causing more serious diseases. The Delta variant, now prevalent all over the world, has confirmed the habit of many viruses to evolve towards one greater inf
activityrather than towards greater lethality. Where it sets itself, Delta has canceled even the most worrying variants of the ability to pierce vaccines. Scientists hypothesize that the only path for the evolution of SARS-CoV-2 now passes from the single mutations of the Delta, in practice sub-variants, in fact in the United Kingdom there are already several subtypes. The adaptation of a virus to humans, however, is a process that does not last forever: there are likely to be some biological limits on how infectious it can become. Meanwhile, natural infection and the boosters of vaccines in use could recharge acquired immunity and teach our bodies to recognize new mutations. The number of susceptible (completely vulnerable) people is also set to decline and the the spread of Covid will slow down, so the virus will have less opportunity to change.
The role of vaccines
The other central variable in the fight against Covid is vaccines. Whether or not the pandemic is retreating depends on the vaccination rate and the diffusion and capillarity of immunization: in some countries there are percentages of vaccinated people that reach 90% of the eligible audience, but in Africa (for example) it falls below 10 percent. The pandemic cannot end as long as infections run unchecked in much of the world.
Another unknown is represented by the number of individuals who they won’t get vaccinated never: how many are there, how are they distributed in the various countries? Children under 12 they are currently excluded from immunization, but until when? How many parents will choose to vaccinate them when there is health clearance? The vaccinations themselves raise some questions: they have proved extremely effective against Covid disease, they are not totally effective against the possibility of infecting it. The vaccines in use are not sterilizing, so they do not break down (even if they severely limit) the circulation of the virus. They may, however, be updated and repeated in the future. THE recalls they have been studied precisely because the immunity given by vaccination seems to be weakening (it seems on average after about 6 months); on the other hand, we do not even know exactly how long the immunity acquired with natural infection will last.
Closures and human behavior
All these factors make up the picture that draws the future of the pandemic. Finally, it should not be forgotten that i human behavior count a lot, as we have seen and studied: before the advent of mass vaccination, any drastic reduction in the circulation of the coronavirus in a given country was obtained with closures and distancing measures, more than for the barrier constituted by the percentage of population already infected with the virus. The sighed herd immunity, it turned out, a c
himera
, given that vaccines do not completely stop the infections and a certain spread of the patchy virus, depending on the state and area, to be taken into account.
Flu or cold
In this context, when will the number of healed and vaccinated transform the virus from pandemic to endemic? Evolution will likely take place at different times in the world, due to the different distribution of vaccines and the transition will not be sudden. Scientists are making several hypotheses about what coexistence with an endemic virus will be like: some predict that Covid will be very similar toinfluenza and may still cause serious illness and death, especially during seasonal peaks, others are more optimistic and believe it will become more like a common cold.
The main hypotheses
Alberto Mantovani, scientific director ofHumanitas Clinical Institute and president of the Humanitas Research Foundation, for Italy assumes one long coexistence with SARS-CoV-2, especially until the gap between the countries of the world regarding vaccination rates is bridged: We clearly see the light at the end of the tunnel – he declared on these pages -, but it would be necessary to vaccinate the entire population from 12 years and up, including the healed, and don’t abandon the tracking of positives and the rules of prevention in closed places.
Maria Van Kerkhove, head of the Emerging Diseases Unit of the World Health Organization (WHO), thinks of periods of ups and downs: Spikes may become lower, but more acute in specific populations, such as the unvaccinated and the frail.
Trevor Bedford, computational biologist at the Fred Hutchinson Cancer Research Center of Seattle, calculates Covid will be the worst of seasonal respiratory diseases: I guess a virus three times more contagious than the flu, but with a similar death rate.
It Statens Serum Institute Danish (SSI) links the increase in cases to the vaccination rate and the level of reopenings: the UK lifted all restrictions on July 19, when only about half of the population was fully vaccinated, and cases began to rise early. in August, up to today over 38 thousand new positives per day and an average of about 150 daily deaths.
In the magazine Science the hypothesized scenario is that of a common cold, in which protection from infection erodes over time, but defense against serious diseases does not. This could result in a first infection in childhood, followed by recurring mild infections.
Whatever happens, encountering the coronavirus periodically, backed by the protection of a vaccine or a previous infection, could help refresh the immune system’s reaction. making us even more suitable for long coexistence.
October 17, 2021 (change October 17, 2021 | 09:53)
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