Delta variant, from “different symptoms” to the effectiveness of various vaccines: this is what we know

What are the symptoms of Covid-19 triggered by the Delta variant of the virus? Apparently, but certainly more data will be needed, slightly different than the previous ones. Perhaps also because the disease is affecting people who are not vaccinated but largely belonging to youth groups.

A good starting point for understanding what they are is the British project Zoe Covid Symptom, coordinated by the epidemiologist of King’s College London Tim Spector: this is an application that was created precisely to collect the widest possible series of symptoms from patients.

In the case of the Delta variant (scientifically known as B.1.617.2) the main signals are headache, runny nose and sore throat. A symptomatology largely attributable to the upper respiratory tract: «Symptoms in young people are more similar to a bad coldSpector explained to Bbc, specifying that loss of smell and taste, typical of Sars-CoV-2 infection and which had been much discussed, “seem less common” when one is infected with the strain first identified in India. Even, loss of smell no longer appears in the top ten symptoms reported by people.

On closer inspection, in the absence of a positive swab, the very fact that the disease given by the Delta variant is for many patients rather mild or at most moderate, and easily confused with a bad cold, could have played the game of infection by assigning it a R0 much higher than the other strains: people would be led to underestimate it, and not to take a control test, continuing to lead a normal life and thus spreading the infection. «These are forms of viruses, I repeat, with a rather low clinical profile, which therefore cause few problems. This is fortunate, of course. On the other hand, however, the problem is that i symptoms can be underestimated»He explained to the Nation Renzo Berti, director of the Prevention department of the ASL Toscana centro.

THE EFFECTIVENESS OF VACCINES ON THE DELTA VARIANT

As for the vaccines, there is no need to worry: the completion of the vaccination cycle is effective against hospitalization and severe illness. Infection is another thing: for example, Pfizer’s loss of efficacy on the Delta variant reported by the Israeli authorities concerns precisely asymptomatic or mildly symptomatic infections, not moderate and severe disease. Let’s not forget that until a few months ago that of infections was a front taken for granted: vaccines were developed to protect against disease and death. And this they continue to do with an excellent level of effectiveness even against the Delta and Kappa variants.

The same data from Israel confirm this. Compared to serious Covid-19, effectiveness has dropped by only 5%, going from 98 to 93%. Many other studios seem to go to the same destination and practically cover all vaccines approved by the EMA, then also Johnson & Johnson (which had already intervened autonomously on the point) and AstraZeneca, on the other hand massively inoculated in Great Britain. In detail, against the Delta strain, protection from severe symptoms for Pfizer-Biontech and Moderna vaccines drops from 90-95% to 85-90%, while for AZ it drops to 65-70%. A single dose, on the other hand, protects much less: between 20 and 30%. Another Canadian study, for example, would have estimated the protection at 87% for Pfizer, 72% for Moderna and 67% for AstraZeneca. As we explained earlier, those who risk the most are those 2.5 million people over 60 that have not manifested themselves to the health system and have not received even a dose of the vaccine: they could be the target of the disease in the fall, and already in the coming weeks. Anyone who knows one should convince her to get vaccinated immediately, net of specific situations.