For some days we have been reading, in newspapers and other media, including scientific ones, of a new autumn-winter epidemic phase, of SARS-CoV-2 in our and other countries. Here, some data seem to give substance to the event. In the last week (period 3-10 October) infections increased by more than 20% compared to the previous week, in which significant increases had already occurred. You know, these numbers alone do not say much, they are largely underestimated because the swabs performed are few and many in self-diagnosis do not know the outcome. More important is the significant increase in hospitalizations and admissions to intensive care (here 199 subjects, very small but 60% more than the previous week).
Infected with Omicron, there could be many more asymptomatics than we know
by Aureliano Stingi
It is not yet known whether and to what extent the increase in infections will correspond to a real new and long epidemic wave. It may be that it is just a replica of the small wave of this summer, that hump of the epidemic curve from mid-June to mid-September, with a peak of infections around July 30, and like this one destined to run out soon. It causes the same virus. Omicron BA. 4/5, dominant now as then but to some extent reinvigorated by the approach of the winter season, with an increase in the chances of contagion in closed and crowded environments and subjects without masks (see schools and public transport). It should be considered that having contracted infection with the first two Omicron variants (BA.1 or BA.2) in the spring-summer of this year could protect little from the BA4 / 5 infection against which we have just begun to vaccinate us.
Covid and flu, a double epidemic on the horizon
by Donatella Zorzetto
The problem, however, may not be BA 4/5. What is actually feared could trigger a real and robust winter wave is the presence, here and there in the world, of variants of the virus, more or less legitimate daughters of Omicron, hyper-transmissible and resistant to neutralizing antibodies generated by the infection or from vaccination against Omicron BA.4 / 5. For their denomination, the Greek letters now exhausted, the mythological characters were passed, from Centaurus, the BA.2.75, up to Cerberus (nomen omen!) The variant BQ1, this certainly daughter of BA.4 / 5 which is said to be rapidly growing in the UK.
Covid among the desks, the alarm of the experts: “The virus runs more at school”
by Fabio Di Todaro
Will one of these succeed in establishing itself as capable of supplanting the current variant and causing a real, new epidemic wave, as happened with Alpha, Delta and Omicron? We will see. The opinions of those who work there are divided and the epidemic genius remains unfathomable. On the other hand, as we do not yet have vaccines capable of conferring lasting protection against infection and its transmission in the population, we cannot avoid that the variants are generated and the most transmissible ones are selected and which better evade anti-infective immunity. .
No, we will not go back to 2021
Does all of the above mean that we should expect a winter like 2021 or worse, 2020? Not only without gas and with war in Ukraine but also with more and more dangerous viruses? If there will be a hard and pure wave, what can we expect from its impact on the disease, Covid-19, in particular its severe form, the one that requires hospitalization? The answer to these two questions is a decided NO, the new wave, whatever its duration and intensity, will have nothing to do with what we have suffered in the past two years and I would like to explain the reasons here.
Covid and variants, in November it will be Cerberus time
by Donatella Zorzetto
Never as in this pandemic have we been instructed on the substantial difference that exists between infection, i.e. the presence of a pathogenic microorganism on the surface (skin and mucous membranes) or inside our organism, and disease, with its signs and symptoms, which eventually follows. Regarding the disease, two fundamental things have emerged so far. The first is a lower degree of aggression, that is, the inherent ability of the Omicron variants to cause severe disease in humans, compared to the original Wuhan strain and the Delta variant. Not that their aggressiveness is exactly the same as there are differences in experimental pathogenic power between Omicron BA.1, BA.12.2 and BA4 / 5, as some data from Japanese authors suggest, but the differences have not so far translated into human pathology.
Will they still have low pathogenicity?
Obviously we do not yet know if the upcoming variants retain Omicron’s general low pathogenicity but everything suggests that the gain in transmissibility and immuno-evasion will not translate into one of pathogenicity. In this prediction, we are comforted by the absence of significant variations in the aggressiveness of the virus in the transition from Omicron BA.1 to Omicron BA.4 / 5 and, more importantly, in that from Omicron BA.5 to Centaurus, the BA.75.2 . As for Cerberus, we’ll see if it bites us more!
And then there are our T cells
The second, as well as decisive, factor to take into account in our predictions is the ability of some antibody and especially cellular components of the immune response, in particular consisting of cytotoxic T lymphocytes, to recognize epitopes common to the original strain (and also in part to coronaviruses common of our cold) and its variants, from Alpha to Omicron, as demonstrated in a brilliant paper published by the prestigious magazine Cell, also signed by Alba Grifoni and Alessandro Sette, in La Jolla, California. These cells are activated and expanded in a large pool of immune memory cells following the vaccination course including the third dose and are able to protect against severe disease both people already infected (probably more than half of our population, quite a lot more than the official numbers) and, albeit to a lesser extent, vaccinated people in the age group over sixty are now close to or exceed 90%.
Covid, why don’t some get infected? The hypothesis of viral interference
by Aureliano Stingi
This section of antiviral immunity is even more stimulated in infected and vaccinated subjects who enjoy the so-called hybrid immunity, which all data indicates as a viaticum for powerful and lasting protection from COVID-19. Less aggressiveness of the Omicron variants and robust cellular immunity generated by having overcome the infection and / or by vaccination combine to provide substantial protection from severe disease in this wave.
Also controlled by bivalent vaccines
If that is the case and the new, probably small epidemic wave was just a resurgence of BA.4 / 5 facilitated by the seasonality and freedoms that were rightly granted to us in the Omicron era, it is reasonable to expect it to be well controlled by a large use of current bivalent vaccines, made with spike protein messengers from the Wuhan primal strain and those of Omicron BA.1 or BA.5. I remember in this regard that having done the fourth dose is not equivalent to the new booster because the antibodies generated by the old vaccine are not able to neutralize Omicron BA.4 / 5. 3-4 months after administration, just as having contracted an infection with a pre-Omicron strain little protects against infection with Omicron variants. In this context, it is not surprising that many did not take the fourth dose of the old vaccine in anticipation of the Omicron-calibrated vaccine arriving in September. If we exclude particularly fragile subjects, it turned out to be a substantially correct choice.
Cerberus is the daughter of Omicron
If, on the other hand, this winter we had a new variant, a cerberus on the ankles, how should we behave with the current bivalent vaccine? Would this still be useful to protect our range of fragile people and at risk of a serious event? Despite so much we don’t know about the new variants, I don’t think we would be moving into completely uncharted terrain. Cerberus is the daughter of Omicron and it is very likely that its resistance to anti-BA.4 / 5 antibodies is only partial. However, it would be highly recommended to use the booster with the new vaccine to expand cellular responses even if, in the frail, these responses may be less amplifiable.
Who hasn’t done the third dose
As for the rest of the subjects not at risk of serious disease, healthy subjects at a young age, but with a good level of previous vaccination, in part already largely infected and therefore with hybrid immunity, the availability of the new vaccine remains for those who wish to do so. . However, there is a non-negligible percentage of them who did not complete the primary course with the booster dose of the old vaccine: if not infected, they are at risk of serious disease. They should be highly encouraged to booster the new vaccine. It is just a matter of “reaching them” with a good message because if they have taken the first two doses, they are people who want to get vaccinated.
Waiting for the second generation vaccines
In conclusion, the new wave, whatever it is, a winter tail of Omicron BA.4 / 5 or something more robust connected to the emergence of a new variant of the Omicron group, should not constitute, except for surprises always possible with this virus , a factor of particular concern in the context of the immunity already achieved in the population, the general nature of the viral variants belonging to the Omicron family, a virus with which we have been dealing for almost a year, and the vaccine, pharmacological containment and contrast measures and not, which we already have. It continues to be essential to follow the evolution of the virus, and to study its characteristics of transmissibility and pathogenicity. There remains the problem of the low and transient ability of all current vaccines to block infection and transmission of the virus. The second generation vaccines would be decisive, formulated with more viral components in addition to the spike protein and mucosal administration (nasal or oral). Only with these could we perhaps put a stone on the perfidious crowned one.
* Member of the American Academy of Microbiology
#Covid #wave #dramatic
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