The curve of the Covid-19 epidemic is fluctuating throughout Europe, including Italy, with surges which are followed by often short-term descents: "it is happening in the last two months, in which there have been enormous fluctuations in all countries , not well understood ", physicist Giorgio Parisi, from the Sapienza University of Rome and the National Institute of Nuclear Physics (Infn) told ANSA. The index was initially aimed at the gatherings for the European football championships, then on the reopening, but none of these possible causes seem sufficient to explain the strange phenomenon in progress. Meanwhile, Parisi continues, the first data arrive from Israel indicating how vaccine protection is reduced over time.
The fluctuations of the epidemic leave researchers confused and bewildered, as the journal Nature also recently noted on its website. To get an idea, let's look at the Netherlands, says Parisi, where "in a week the cases have increased by almost seven times and then decreased; Iceland has rapidly gone from 6 to over 100 cases a day and has been stable on 100 cases a day; even in Great Britain the cases have increased rapidly to 50,000 and for a week the situation has been stable at 30,000 ".
In addition to the events that act as 'super spreaders' of the infection, "one would think - says the physicist - that there is a trend underway due to the fact that when the cases increase people get scared and pay more attention". In our country "there was an impetuous increase at the beginning of July, with a doubling of cases every 3 days followed by a very strong slowdown, to the point that now there is a slow growth, with an average increase of 10% compared to the week previous one". For Parisi it is "very difficult to identify a precise logic in these fluctuations" and the "situation is not at all clear".
If this is true with regard to the new cases, the situation is less confused on the front of ordinary and intensive care hospitalizations: in Italy "both are increasing at a sustained rate of 40% per week, probably because the high number is being served. cases in July, and deaths are also on the rise, "he notes. "Certainly - he adds - we have excellent protection from vaccines as regards the severe form of the disease".
It remains to be seen how long it can last. Data from Israel, which began vaccinating the population in January, indicate that protection tends to decline: while in those vaccinated in April it is still 75%, in those vaccinated in January it dropped to 16%.Hence Israel's decision to administer the third dose of Covid-19 vaccine to over 60s.
In Italy, data from the Istituto Superiore di Sanità (Iss) indicate that protection from symptomatic disease is 60%, that is, it shows a decline, while that from hospitalizations exceeds 90%.
Great Britain, which until a few weeks ago regularly published data on efficacy, is recently silent, Parisi notes. For the physicist, the possible reduction in the effectiveness of anti Covid-19 vaccines over time is an aspect to consider right now because, "if the trend that Israel has begun to observe were confirmed, in two or three months we could find ourselves facing a increase in infections "