May 16, 2021

Now that we have the vaccines, what summer will be next?

The new Dpcm, the first of the Draghi era, will be in force from 6 March to 6 April: a month of very few reopening and many bans to prevent the Easter holidays from turning into a free all that gives wings to contagions, to them time driven by variations. Everything is based on data from the epidemiological curve that, after a slowdown due to the “Christmas decree” which led to a leveling (but not a decisive reduction), started to rise again.

Questions about the future

With a semi-armored Easter that reminds us of last year’s, our thoughts turn to the next one spring and the future summer: how they will be? Now that we have the vaccine weapon, what could be the trend of infections ahead of the summer? Could we have a sharp drop in infections, like last year? What are the mistakes to avoid at this stage?

Nothing like before

The first premise that, despite the pandemic is still among us, nothing compares to last year. Let’s start with the variable that in 2020 “allowed” us a more “relaxed” summer: the lockdown. They were two months of almost total closure, especially in some regions. The mobility data, which show that people moved much less, say it, images of deserted roads and highways recall it. For weeks. Not to mention the closed shops, kids and children at home from school until June, the suspension of all sports. The red areas are not like they were then, least of all the orange or yellow areas. The activities did not completely disappear and the children, for the most part, went to school in the presence. The drastic killing of cases last spring (which also took weeks to consolidate) cannot be in the same terms: no one hopes for a lockdown of that type and will do everything possible not to get there. Then, every measure adopted now presupposes a more or less significant amount of virus circulation.

The weapon of vaccines

The second variable at stake, the most important in our favor, is the presence of vaccines. In Italy there are three authorized, but others will arrive. Despite the supply and production problems, we know that, as the months go by, we will have more chances available, given that Pfizer, AstraZeneca and Moderna will be added J&J (soon), Sanofi / GSK and Curevac, for a total of many more doses – on paper – than would be needed to immunize the entire population: 224 million. For candidates not yet on the market, obviously everything will depend on the month of approval by the regulatory agencies and on the ability of the companies to comply with delivery contracts. Another factor in contention, once the doses have been obtained, is the speed of the vaccination campaign, with all the organizational problems we have seen. Not only that: the share of vaccinated people could favorably affect the trend of infections especially if the vaccines are able to also block the transmission of the virus. A fundamental question that has not yet received sure answers: if a person protected from Covid disease because vaccinated can still infect unvaccinated family members, the reduction of the positive curve will be slower, vice versa it will be faster.

The distant goal of herd immunity

There is also the unknown factor linked toadherence to the vaccination campaign: how many will get vaccinated in Italy? Aiming for “zero cases” means aiming for the “famous” herd immunity that can only be achieved with a very high percentage of vaccinated people, without neglecting the fact that to reach this quota, it will also be necessary to vaccinate the guys, but the trials on minors are still ongoing. The last two elements do not even enter into the calculation of the scenarios that lie ahead before the summer, given that for herd immunity (and especially the vaccination of children) it will probably have to wait until the end of the year.

The variants factor

For one last fundamental factor in this “impossible” calculation, another puzzle piece that was missing last year and that makes comparisons pointless: the virus also changed. While restrictions and vaccines play in our favor to bring the longed-for reopening closer, the arrival of variants in Italy slows down any descent of the epidemiological curve. The prevalence of the English variant, which is certainly more transmissible, in Italy could have reached 30 percent in a few days. In some areas, it is already causing hospitals to clog and has led to severe lockouts. It is calculated that the strain B.1.1.7 will become prevalent in March and then the steps in the right direction made with the vaccine will have to deal with the difficulties posed by the English variant, capable of causing infections to increase in the areas where it spreads. The Brazilian and South African variants have also been mapped in Italy and, although the latter has not demonstrated the greatest power of diffusion, they are worrying about theconcrete hypothesis that they can make vaccines less effective, until they are “updated”.

What to do

All that remains is to consider which factors play in our favor and better manage those: restrictions and vaccinations. Speed ​​up the vaccination campaign with every effort, choosing the categories to be protected first, and measure the closures to be imposed so as not to leave the variants free to spread. As well explained in the article by Paolo Giordano and Alessandro Vespignani, “the epidemic to a new culmination of complexity“, Difficult to make predictions.

Summer and the weather

The distant summer and the heat and the open spaces will not help us that much, because they are not decisive by themselves, as we saw last year in the United States, which had their second wave just in the summer. Last year, perhaps it was easier to make predictions: blocking every activity the curve would have dropped, then at a certain point we would have had a rebound – he observes Paolo Bonanni, epidemiologist, full professor of Hygiene at the University of Florence -. Now with the colors of the Regions and the alternating closures of the cities, the variables really become a lot. The only element of certainty similar to last year that, with the caldo, we will shoot more outdoors and open the windows more: if nothing else the viral load will be more diluted in these situations. Uncertainty about vaccine data also complicates matters: we are not sure about the effect of vaccines on transmission of the virus in immunized people. Besides the tracking of vaccinated people, which in case of infection would be pauci-symptomatic or asymptomatic, more difficult.

Scenarios: the best and the worst

What are the best and worst hypotheses? If we had one critical mass of vaccinated, especially among the elderly, sufficient to drastically reduce the seriously ill, we could also decide not to close, but it will be difficult for next summer – argues Bonanni -. Unless the speed at which we are going with the vaccinations increases exponentially so that we arrive in June-July with a 50-60% share of the vaccinated population, as we thought at the beginning. The worst case scenario is that a variant that is little covered by the vaccine comes and becomes predominant, such as the South African variant (which is probably the worst from the point of view of maintaining the effectiveness of vaccines): in that case we would continue to have too many cases and it would change little compared to how we are now. The best scenario could be one in which, despite the English variant becoming predominant (as in all probability it will), we make up for the delays in vaccination and at that point we could have so few cases that we could reopen to free movement.

February 27, 2021 (change February 27, 2021 | 08:04)


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