In Italy on 18 March the prevalence of the so-called English variant of the Sars-CoV-2 virus was 86.7% (it was 54%) with values ranging between the individual regions between 63.3% and 100%. For that Brazilian the prevalence was 4.0% (0% -32.0%) and remained substantially unchanged. The variant South African at 0.1% (it was 0.4%) while the Nigerian, which at 0.6%, almost totally concentrated in the Autonomous Province of Bolzano. These are the data of the latest report on the prevalence of coronavirus variants in Italy prepared by the Ministry of Health together with the regional laboratories and the Bruno Kessler Foundation. In the Italian context in which vaccination is proceeding but has not yet reached sufficient coverage – the note states – the spread of variants with greater transmissibility can have a significant impact if adequate mitigation measures are not adopted. While the English variant now largely predominates, particular attention should be paid to the Brazilian variant also due to a possible partial immune escape. what is underlined in the new rapid survey on variants conducted by the ISS and the Ministry of Health.
The variants
New variants of the coronavirus are emerging around the world. Every day the laboratories around the globe update the databases with new mutations (about four thousand are confirmed, 12 thousand are awaiting validation). Each time the virus replicates it can make small mistakes and from here the mutations arise which, when they begin to add up, generate the so-called variant. Most of these variants mutate into non-relevant sectors of the virus’ RNA that do not affect pathogenicity, explains Pierangelo Clerici, president of the Italian Clinical Microbiologists Association. To date, the variants of greatest concern remain the usual three: English, which is more easily transmitted, South African and Brazilian, because the vaccines in use seem to have less efficacy. However, we are still in an initial phase of mass vaccination globally and it will take at least six months to have more certainty. It is important to underline that no variant, however, proved significantly capable of evading vaccines. There N501Y mutation (common to all three and known to help the virus bind more closely to human cells) and the E484K (shared by the South African and Brazilian variants, which helps the virus evade antibodies), they have developed autonomously on several continents, a sign that they are the right keys to making the virus more efficient. These are mutations in the Spike protein, that is, the attachment to the Ace receptor, and therefore easier to diffuse. The most effective way to hinder the spread of variants, in the unanimous opinion of the experts, is to accelerate the vaccination campaign as much as possible.
The English variant
The English variant (B.1.1.1.7) was first identified in September 2020 in the UK. The mutations it has accumulated on the spike protein certainly make it more transmissible. The new report just released evaluates its higher transmissibility of 37%. Other surveys speak of 50-60% more (a latest study in Nature even reports up to 100% more). Some research shows that the English variant also increases the risk of hospitalization and death (greater lethality, from 40 to 60 percent more) even on younger age groups, however the investigations are still preliminary. The effectiveness of the vaccines in use in Europe and Great Britain (Pfizer, Moderna and AstraZeneca) does not appear weakened against the variant. The survey indicates that the variant at the national level has a prevalence of 86.7% (totally dominant in the Aosta Valley and in the province of Trento). 89% in Lombardy.
The Brazilian variant
The Brazilian variant (P.1) was identified in Japan in January 2021 in two travelers from Brazil. It appears to be slightly more transmissible (1.4 to 2.2 times) and able to evade the protective immunity caused by a previous Covid infection. This variant began to spread in Manaus, in an area heavily affected by the first wave and it was expected that few people would be affected by the second wave due to the immunity gained from the first infection. On the other hand, both in the field and in the laboratory, it has been seen that the Brazilian makes antibodies less effective and can therefore cause reinfections. The Moderna and Pfitzer vaccines appear to be slightly less effective, from 4 to six times less, but the decline was not judged to be heavy and the high number of neutralizing antibodies maintains a strong immune response. Brazilian by 4%. The Italian region with the highest prevalence of the Brazilian variant is Umbria with 32% (the last monitoring was 36%) followed by Lazio (20.5%), Liguria (13.6%), Molise (12.5%). ) and Tuscany (10%).
The South African variant
The South African variant (B.1.351) was identified in South Africa in October 2020. It appears to be most transmissible and the one of greatest concern due to a lower sensitivity of vaccines towards it. Moderna and Pfitzer are slightly less effective, Johnson & Johnson reports an effectiveness of 57% (compared to 72% in the United States). A small study of two thousand individuals showed that the AstraZeneca vaccine seems to work even less against the South African variant to prevent mild and moderate disease, so much so that South Africa has suspended the inoculations (but more data is needed for a certain evaluation). Let us remember, however, that the first dose immunizes only up to a certain point and each individual matures antibodies in different quantities. The second dose is needed for important protection and in the meantime infections can arise, adds Clerici. In Italy this variant is still not very present. According to the report, it has a prevalence of 0.1% (0.4 in the last report). present in Sardinia (4.8%), in Veneto (0.6%), in Lombardy (0.3%).
The Nigerian variant
The Nigerian variant (B.1.525), was first detected in Britain in mid-December 2020 and has been linked to a trip to Nigeria. In Italy she was isolated for the first time in Naples. It shares some similarities with the English variant and a mutation, the worst, E484K, also present on the Brazilian and South African variants, which allows the virus to partially escape from antibodies and weaken the effectiveness of vaccines. In Italy it appears for the first time in this report and is almost totally concentrated in the autonomous province of Bolzano (13.3%), in Sicily (2.3%), in Veneto (1.9%), Lombardy and Tuscany (1%) ).
Covid and variants: the insights
The other variants
In Italy other variants have also been identified, but none of these – Clerici clarifies – is problematic because they have remained limited. In March, two cases of the New York variant were identified (B.1.5261), discovered in New York in November 2020 where it rapidly spread. New variants have also been reported in Brescia, in Varese in the Marche but do not cause concern: These are temporary mutations that have not been confirmed in other situations that limit themselves otherwise we would see high percentages of those too, concludes Clerici.
March 30, 2021 (change March 30, 2021 | 20:59)
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