New variants and old habits, such as stemming the Covid river

New variants and old habits, such as stemming the Covid river
New variants and old habits, such as stemming the Covid river

London has focused on vaccines but has let the virus circulate – Ansa

The Covid-19 pandemic, more than twenty months after its onset, appears as a rushing river whose waters, once the banks have overflowed, continue to flood lands and villages. Vaccine prophylaxis works like retaining walls to protect the more fragile buildings downstream: it gives excellent results in safeguarding the life of the elderly, serious patients and multi-pathological subjects with the most aggressive forms of infection, and this is certainly good for them, for doctors and nurses in intensive and sub-intensive wards, and for the health system, which is prevented from collapsing.

But – and this is indisputable in terms of clinical studies – current vaccines, which are not of the “sterilizing” type (do not prevent infecting and infecting; they only reduce the viral load that develops in the infected person and the probability of onset of a major symptomatology), leave the way open for the spread of the virus in the population, albeit widely vaccinated, if they are not systematically and seriously adopted – this time upstream, close to the soregnte – other robust prophylaxis measures, those of a physical type that create a “barrier ”Against viral transmission (masks, distancing etc …).

Just like the water that flows and is always renewed in the stream bed, the Sars-CoV-2 virus, like others, is constantly evolving, it does not remain identical to the one that originated the pandemic. For this reason, we are immersed in a pandemic picture that is not the same as last year. Among the thousands of genomic variants of the virus identified so far, those of potential clinical and epidemiological significance are classified as “variant under investigation” (Vum), “noteworthy variant” (Voi), “worrying variant” (Voc) and “variant with high consequences “(Vohc).

So far no Vohc has been defined (the one that would completely evade current vaccinations), while there are four Vocs: Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1) and Delta (B. 1.617.2). The latter is responsible for the vast majority of Covid cases currently identified in Italy, Europe and the USA. The Voi are two, Lambda (C.37) and Mu (B.1.621), isolated in South America. One of the twenty variants derived from the Delta, the AY.4.2 (Delta plus), which has so far been significantly present in England, is about to enter the Vum (currently there are 16), where it spreads and has reached over 6% of the positive swabs sequenced. In our country there are over 90 Delta plus sequences recorded so far.

Not unfounded are the concerns among experts for this variant, which presents two further mutations in the amino acid chain of the Spike protein, A222V and Y145H, also present in other strains identified so far. Preliminary evidence suggests that the Delta plus may be 10-15% more transmissible than the Delta and the suspicion that it will be able to replace it as a prevalent variant in the UK in the coming months (and from there to expand into Europe and the US).

At the moment there is no evidence that it can give rise to serious clinical pictures of Covid more frequently and the status of early warning in England is growing. The United Kingdom has implemented a robust vaccination plan but has been less attentive to physical prophylaxis, thus allowing the virus to circulate at high levels while keeping hospitalizations and deaths related to Covid contained. This favors the onset of variants and the selection of the most aggressive and elusive, because genomic mutations arise in a way that is directly proportional to the number of replications of the virus in human cells, both of vaccinated and unvaccinated, and in the latter the variants undergo also a selection process by immunization, ie those less easily neutralizable by antibodies survive preferentially.

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