The Fallacy That Vaccinating 70% Achieves Group Immunity: "we Don't

The fallacy that vaccinating 70% achieves group immunity: “We don’t know when we will reach it”

Specialists do not consider 70% vaccinated as a “magic” figure that justifies the lifting of measures.

A health worker performs a coronavirus detection test.

The concept of group, or herd, immunity is one of the most slippery of all that we have learned with the pandemic. It is very easy to define it: the indirect protection that is achieved when a population becomes immune as a result of vaccination or having passed the disease. That is Even if you are not vaccinated or have not had Covid-19, you are protected against it because everyone around him is immune.

However, in practice, no one really knows when herd immunity will be reached. “The 70% is a goal, but the immunity situation requires higher figures,” he explains. Vincent Martin, professor of Public Health at the University of León. “What is going to happen is that hospitals will be more controlled, with few admissions and patients in the ICU.”

The current vaccination strategy, he points out, is not designed so much to achieve group immunity as “so that people do not die or enter hospitals and that they do not become saturated” because, in reality, it is not known when we will reach herd immunity.

“It will depend mainly on the variants that arise and their ability to escape from the vaccine,” he observes. In this way, although he admits that the lifting of some restrictions will be considered as the vaccination campaign enters the final stretch, he considers that we will continue with many of them, such as the mask (at least in closed places) and the safety distance. , For a long time.

In fact, the presence of new variants is what led at the time to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases of the United States and the main scientific face against the pandemic in that country, to affirm that we may need up to 95% vaccination to be able to speak of group immunity. Other experts go further and are directly inclined to forget this concept, given the appearance, with some frequency, of new variants.

No fear of new variants

However, some specialists see excessive alarmism in these speculations. “What is clear is that, in vaccinated people, the incidence of Covid is falling radically,” he says. Julian Dominguez, Head of Preventive Medicine at the University Hospital of Ceuta. “And now we have the British variant on our territory.”

Regarding other variants, such as the South African one, “it is not being said that the vaccines are ineffective, but that their effectiveness is inferior,” he warns. “It will depend on the number of people to be vaccinated, but studies indicate that vaccination is having a group immunity effect: in the United Kingdom there have already been days with zero deaths. The deduction is quite simple.

The preventivist points out that group immunity can be achieved even with a single dose of the currently available vaccines, it would only take a higher number of inoculations.

Contrary to Martín, Domínguez believes that, given the good results of the vaccines, we can reach this long-awaited herd immunity even before August 18, date given by Pedro Sánchez to reach the magic number of 70% of the population vaccinated with two doses.

“If we extrapolate the data from Ceuta, a city of 80,000 inhabitants that with 25,000 vaccinated we have 0.1% of infections, we can get a guiding idea of ​​what can happen.”

uncertainties of the future

In any case, could you lift stockings? No way. Political leaders, such as the president of the Xunta de Galicia, Alberto Nunez Feijoo, have advanced the end of the masks, something that has already been answered by Fernando Simon, which advocates waiting to reach that 70% of vaccinated.

But Dominguez goes further. “We have a lot left [para levantar todas las restricciones] because we can’t know for sure what percentages we need to achieve herd immunity.”

And he stresses: “We have to be cautious, there are uncertainties regarding the new variants that may arise, the behavior of people and other circumstances that cannot be predicted. This is not the time to set dates for the relaxation of individual preventive measures or, in any case, the reduction of some general restrictions”.

The end of August will arrive, presumably, with almost three out of four Spaniards vaccinated. If we add the around 12-15% of people who have had the disease, the number of immune in Spain will far exceed 80%. The masks, as a precaution, will have to remain on.