“Experts are beginning to believe that the country is about to achieve something that barely seemed possible weeks ago: herd immunityWith this resounding phrase, the prestigious medical journal The Lancet does a little review of the situation of the pandemic in Spain.
At a time when the Netherlands reintroduce social distance, masks and reinforces other anticovid measures due to the rebound in infections or the United Kingdom has a cumulative incidence 20 times higher than the Spanish one, the figures for Spain invite optimism. An optimism, yes, that with the arrival of the cold it cannot be more than moderate.
Group immunity: target or chimera
There are a handful of elements that make The Lancet plantee the possibility that Spain is close to the group immunity. The first is the vaccination rate. Day by day, Spain already has more than 80% of the population vaccinated with the complete regimen. This percentage places us in third place in the world rankings and, as far as we know, coverage is going to be higher in the coming days as the third dose is injected in risk groups (along with the flu campaign) and the two million vaccinated with Janssen come get a souvenir dose with RNA vaccines.
The second element is the good evolution of epidemiological data not only in the vaccinated, but even ** in children and adolescents (vaccinated or not) **. In the 12-19 age group (who now also have rates above 80%), the infection rate has dropped from 154 to 30 per 100,000 people. But it is that in those under 12 years (group not yet vaccinated) the rate has also plummeted from 150 to 54 per 100,000. This last piece of information is what gives rise to talking about ‘herd immunity’.
However, “still we do not know the exact proportion of the population that needs to be immune to achieve immunity collective for SARS-CoV-2, as we need to better understand the duration and protection of transmission generated by both vaccination and previous COVID-19 infection ”, explained in The Lancet Jesús Rodríguez Baño, head of infectious diseases at the Virgen de la Macarena Hospital in Seville. This, as we have explained on several occasions, is true: “herd immunity” is an index closely related to the transmissibility of the pathogen and until we weigh the effect of vaccinations in real life well, it is difficult to pin down an exact figure.
“However, the situation in Spain may give some clues,” continued the Sevillian doctor. “After leaving behind most of the control measures in the population, the contagion rate (and especially the rate of hospital admissions) has been decreasing “. Just the opposite of what happened in previous waves. And precisely what, according to Rodríguez Baño, allows us to assume that”the only plausible explanation is the very high vaccination rate in the country”.
If you look at countries like Denmark and Norway (countries both with worse vaccination rates), we will see that the contagion curve has tended to rise as social distance measures were withdrawn. This is something that is not clearly seen in Spain, but it is true that the weather has helped. Winter in northern European countries has come earlier and, in the coming weeks, we will see the effect of the population’s behavior change on the Spanish incidence. It will be then when we begin to see if “herd immunity” is close or not.
Be that as it may, it appears that we are approaching the point of the pandemic where returns from sanitation measures begin to rise. be decreasing. The “zero COVID” strategy has already been proven very troublesome where it has been applied and countries like China fear the effect of the delta variant in the country: Everything seems to indicate that we have to learn to live with the virus and there is no point in waiting much longer before introducing norms with a vocation for permanence. Immunity or not, in the coming months we will have to tackle this debate once and for all.
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