Friday, July 30

From the success of the vaccination to the lack of control of infections in two weeks: why are the waves in Spain so explosive?

On June 22, the 14-day cumulative incidence (AI) of COVID-19 in Spain culminated the decline that had been registered since April 24 and hit the ground this year with a rate of 92.25 positives per 100,000 inhabitants . The curve bounced that day and began to climb. Slowly, at first. On June 28 the AI ​​was 100. On June 29, 106, a rise of 6% in 24 hours. The graph began to gain verticality. June 30, 117 (+ 10%). July 1, 134 (+ 14%). July 2, 152 (+ 13%). Now it is around 279, which means that in the two weeks since the lowest point of the year the incidence has tripled (+ 203%, specifically).

For comparison, in the third wave – the one that occurred at Christmas and which was the one that expanded the fastest and left the highest numbers of infections – the 14-day AI went from 272 on January 4 to 899 on the 27 of that same month : it tripled in just over three weeks, although it is also true that in that case the incidence started from above and reached a much higher point. What’s going on? Why is the incidence rate soaring at this rate when more and more people are vaccinated (and, although they may continue to infect, it is increasingly clear that they do so much less)?

Evolution of the curve of new cases, admissions, ICU and deaths in Spain

Evolution of
number of new cases, hospital admissions, ICU admissions Y daily deaths in Spain. The cases are shown by date of diagnosis, admissions and ICU by date of admission and for the deceased by date of death. Click to see the detail

The data only includes cases confirmed with an analytical test and the figures for the last weeks are underestimated due to delays

Source: Ministry of Health

This graph shows the intensity of this fifth wave: the incidence rises at the same speed as the third.

The experts consulted to prepare this article speak of a double situation that has caused – or favored – the explosion of this rise: on the one hand, the paradox that the good progress of vaccination and the (relative) good evolution of the incidence, declining until June 22, have led to a general relaxation, but especially among the youth group, who neglected security measures. On the other, the coincidence in time of the elimination of certain restrictions (especially those of nightlife) and of a kind of “Christmas in summer” with the celebration of meetings and parties concentrated in a few days, in reference to weekend trips. of course.

“A perfect storm”

Quique Bassat, epidemiologist and researcher at ISGlobal, defines it as “a perfect storm” due to the conditions of the country, of the group that is registering most of the positives and the characteristics of the more contagious Delta variant. “Transmission is concentrated, which is up to five times higher, in a specific age group, which is not protected by vaccines, which has no perception of risk [porque sabe que la mayoría de los casos son leves o asintomáticos], and that, therefore, they incur risk attitudes without being aware that they are going to be infected “.

It is enough to take a look at the breakdown of incidence by age groups to see that, on this occasion, it is young people who are pulling infections up. The four groups that are registering the most positive in this wave are, mainly, those between 20 and 29 years old (AI of 882) and those between 10 and 19 (636). Then come the least young from 30-39 (329) and those from 40 to 49, already below the average at 168, all of them data from this Friday.

The incidence of recent infections in each age group

Evolution of the incidence of cases in 14 days per 100,000 inhabitants in each age group since March 2021

Ildefonso Hernández, spokesperson for the Spanish Public Health Society (SESPAS) and who was director general of Public Health from 2009 to 2011, points out that “you have to be prudent”, but points out that, to everything Bassat says, “he joins a general public perception that things were on track and that it didn’t matter that much if someone got infected [en el caso de los jóvenes] because it was going to have a favorable prognosis and / or it was not going to infect anyone. “Hernández does not believe that ignorance has played any role in this case:” It is not that people do not know what to do, they know it perfectly especially young people, who have been taking measures in their schools for months, for example. “The problem, he elaborates, is that until now the” nudges “went in both directions (towards prudence and towards relaxation),” but in this In case they all go in the same direction. ”

This expert explains that the paradox may have occurred that the good rhythm of the country has been counterproductive in this specific case, projecting a false sense of security. “There is a mixture of things that may have contributed to people having lowered their guard against preventive measures. It is very likely (although it should be verified by asking them) that the feeling that the elderly were protected has contributed to this thinking that You only take the risk for yourself and you care less if you are young “because you think that even taking it is not going to be serious. The problem with this reasoning, he adds, is with these increases in incidence, the transmission becomes general and gets out of control.

Pedro Gullón, also an epidemiologist, points to the coincidence in time and space of a series of circumstances. “There were elements that pointed to an increase in incidence, but from there to this explosiveness there is an exponential leap,” he says. What elements? “The decrease in restrictions on nightlife, which has not been sequential but suddenly, related to end-of-year trips and the increase in super-contagious events.”

Christmas in summer

Gullón establishes a parallel between this situation and what happened in the third wave, at Christmas. “It has a similar effect: you get together with people you don’t see that often, in a short period of time, but in this case instead of being in small houses, it is in large spaces, like discos.” Add in the high infectivity of this strain and there are the super contagious events.

It has also influenced, experts argue, that in this case Spain started from a worse situation than last summer, with an incidence that did not drop from 90 compared to 20 12 months ago. “It is more likely to explode like this,” observes Gullón.

This epidemiologist also believes that this could be one of the differential factors of Spain with respect to the rest of Europe, where, except the United Kingdom and Portugal, the incidence is notably lower. “Although they are also on the rise,” he observes, “they start from a lower situation because they took tougher measures” during the spring, and with this starting point it is easier for the incidence not to skyrocket as much.

Bassat points to this theory and points out the differences with other countries in this area. “The lack of agility and proactivity of those who have to do something to respond to the challenge, we are champions of looking at things from the sidelines and not acting,” he says. Gullón adds that “the great weight of tourism and nightlife in the country’s economy means that it has to be opened earlier, in other countries they have held out longer.” And, again, back to the same thing: population susceptible to infection, together in the same space and in an environment of non-compliance with the few security measures that remain in nightlife “because people come to have fun” and it costs more keeping your mask on, for example.

Despite everything, and the difficulty of venturing how the situation will evolve, these epidemiologists trust that after this moment of end-of-year trips, with the communities asking for more restrictions and vaccination advancing and reaching the youngest groups, the situation stabilizes. “It is difficult to predict, but it is possible that given the situation and the increase in cases, the perception of risk changes and the incidence begins to decrease,” Hernández closes. But along the way, Tercia Gullón, “we must reinforce all the services where the healthcare pressure of this new wave is falling, since there are fewer cases in hospitals, everything is coming in Primary Care, the monitoring of cases and their contacts and putting restrictions in the most risky places, such as closed nightlife venues “.

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