A Health column to answer readers’ doubts about Covid. A way to examine news and information that sometimes turn out to be hoaxes. Here is the first question that came to the editorial office. If you have any questions to ask the editorial staff, write to: [email protected].
The question
Hello, I gladly read your article in the health column on mRna vaccines and I thought that another important article to help vaccination could concern the explanation of why in Israel and Iceland despite the large number of vaccinated the situation seems to precipitate. As a restaurateur I am lucky enough to talk to hundreds of people every day and when I talk to those who have not been vaccinated, the first example that he brings to support his thesis is that of these two nations.
Letter signed
The answer
Many ask: if the vaccine is effective, why in Israel has there been a new increase in cases? Precisely in the country with a timely and widespread prophylaxis campaign, among the first to show results. Herd immunity seemed a step away. In May the beaches were crowded, the places were full again, people moved in the open air without protective equipment. The most anticipated figure on April 23: 0 victims in 24 hours, had not happened for 10 months. With a decree of June 15, away the masks even indoors. Then the sudden resurgence of infections linked to the Delta variant, and the change of direction by the government, just 10 days later, to which was added the postponement of the reopening of the borders and the restoration of the tampon centers that had been closed .
In Iceland, a nation where 91.2% of people over 18 have received at least the first dose, since July 12 there has been an increase in daily cases. In just over a month, the total number of infected individuals since the start of the pandemic has risen by about 2,100. To better interpret these phenomena, we talked about it with the doctor Flavia Riccardo, infectious disease doctor and researcher at the Istituto Superiore di Sanità.
How do you explain the upsurge in cases in Israel, which months ago seemed close to herd immunity?
“The Delta variant of the Sars-CoV-2 virus, currently prevalent in Europe, has a higher transmissibility than those previously detected. This is why very high immunization levels with completion of the vaccination cycle are needed to acquire, even temporarily, ‘herd immunity’, that is, a level of immunization that drastically limits the circulation of the virus within the population. The spread of the Delta variant in Israel is linked to the same factors as in the countries of the European Union. The increase in viral transmissibility, the mobility of people and the frequency of aggregation events favor the widespread circulation of the Sars-CoV-2 virus in a context where the impact of the disease in terms of clinical severity and deaths is mitigated, but not completely eliminated, thanks to vaccination “.
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And in Iceland?
“The situation is similar. If we look at the data published by the ECDC (European Center for Disease Prevention and Control), countries such as France, Greece, Lithuania, Estonia, this week have higher risk levels than Iceland itself”.
In addition to the spread of the Delta variant, did the suspension of restrictions (distancing, protective devices, closure of services) have an impact?
“It is a combination of factors. The effectiveness of the vaccines made it possible to manage the phenomenon, without drastic closures of the activities. However, it could not avoid the widespread circulation of the virus”.
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What is the paradox effect?
“In a population with high levels of vaccination, infections in fully vaccinated subjects become more numerous. Let’s take an extreme example: since the effectiveness of vaccination prophylaxis is never 100%, in a population where everyone is vaccinated, some cases However, the phenomenon should not be immediately attributed to the poor efficacy of the vaccine. When this is effective, in fact, the data is also associated with a drastic reduction in hospitalizations and deaths, precisely in vaccinated subjects. more frequent in the age groups with high vaccination coverage, the most fragile and most at risk of complications related to Covid-19. To confirm this, the data of these weeks show how the number and incidence by age group of serious cases and deaths in the unvaccinated population are higher than those observed in the fully vaccinated population “.
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How to interpret the data in the comparison between vaccinated and unvaccinated in order not to lose confidence in the prophylaxis campaign?
“We must not only look at the raw data on the number of cases by age group, but also the incidence data: the numerator is the new cases, hospitalizations or deaths, the reference population in the denominator. If we compare the incidences of cases, hospitalizations and deaths in the unvaccinated population and in the fully vaccinated population, we observe higher severity and lethality in the unvaccinated population “.
Over the years, will we have to get used to living with Sars-CoV-2 and its variants?
“The virus is likely to become endemic, as is the case with other respiratory infections that we are used to fighting with vaccination and prevention through behavior. However, as natural and acquired immunity to infection increases along with the specific therapies available, we expect a gradual reduction in the severity of the disease and its impact on people and health services. ”
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