Article by Mónica G. Salomone, science journalist, SINC

Modesty apart, we are one of the few countries that have already given at least one dose to more than 70 % of the population.How have we achieved this? It is useful to know this in order to establish what must be improved in the future and, conversely, what to avoid. What is clear – as experts warn - is that we must not let our guard down.

Worldwide statistics on the progress of vaccination speak little of global success: in many countries, the percentage of vaccinated people is of less than 2 %. But in Spain, for example, where vaccines are available, the country “is a role model with its excellent vaccination figures,” as Astrid Wagner, a researcher at the CSIC's Institute of Philosophy,has told SINC. “It's a good time to appreciate and analyse the successes,” she adds.

In countries without shortages, which assume asimilar logistical capacity, the progress of vaccination depends on the willingness of citizens to be vaccinated. “We’ve had to queue for hours while other countries offered beer for vaccination, and even that hasn’t worked that well,” Pep Lobera, a sociologist at the Autonomous University of Madrid, has pointed out to SINC.

The explanation for Spain's triumph lies not in one, but in many pro-vaccine factors that have been feeding back on one another. Lobera speaks of a “snowball”.

But the metaphor of the house of cards also applies, describing the need to understand the reasons for our success. If vaccination has grown on the basis of mutually supportive factors, it is important to identify which ones act as the main wall; if they weaken, the house of cards collapses - and refusal to vaccinate increases.

There was reluctance, but the evolution has been positive

Firstly, Lobera insists that “it’s not true that there’s no controversy about vaccination in Spain. In fact, there is.” He goes on to say: “The range of opinions is very wide. There are people who were very clear about it, people who had doubts and have been vaccinated and also people who believe in conspiracy theories. But the factors that have driven the snowball in favour of vaccination have predominated.”

Wagner also highlights this diversity ofpositions: “There are different forms of opposition to vaccination: those basedon deep-rooted ideological reasons, others based on very specific fears orsocial circumstances, others based on insecurity caused by hoaxes, etc.”

It is therefore not easy to identify the factors at play. The number of vaccinated people is known, but the individualmental mechanisms that generate it remain concealed in a black box. “We knowthe final product of a decision, but we don't see what's behind it,” PabloSimón, a political scientist at the Carlos III University in Madrid, has saidto SINC.

Throughout the pandemic, several surveys have opened up peepholes in the black box. COSMO-Spain, conducted by the Carlos III Health Institute and the World Health Organization, has been publishing results every two months since May 2020. The Spanish Foundation for Science andTechnology (FECYT) has conducted three Covid-19 Social Perception Surveys, in June-July 2020, January 2021, and May 2021. Their results are to be found in the report Evolución de la percepción social de aspectos científicos de la covid 19 (Evolution of the socialperception of scientific aspects of Covid-19).

These studies reflect changes in the intention to be vaccinated according to how the pandemic unfolds. As Maria Joao Forjaz, an epidemiologist and researcher at COSMO-Spain, wrote in The Conversation, “in July 2020, 70 % agreed to be vaccinated; this number dropped to around 40 % in November 2020 and rose to 72-74 % after the third wave of the pandemic, at the same time as the vaccination campaign began.”

The FECYT study confirms the positive trend. “Trust in vaccination has been rising steadily since the end of December,” it notes. “In May, only two out of 30 Spanish residents expressed any reluctance to accept vaccination.”

A matter of trust and solidarity

In this evolution, the first key factor pointed out by experts is trust in doctors, scientists, and the public health system. “A willingness to be vaccinated is always a matter of trust,” Wagner stresses.

For Txetxu Ausín, from the CSIC's Institute ofPhilosophy, “in Spain, there’s more trust in science than in other countries, and this is far above the scant credibility of other institutions such as the monarchy, political parties or the media. This confidence in research, and therefore in new vaccines, is a crucial element.”

Indeed, in all the COSMO-Spain rounds, scientists, hospitals and health centres emerge as the most trusted institutions. The FECYT study also confirms that trust in institutions is central to a lower spread of conspiracy theories, as is stated in the conclusions.

Other key elements in the success of vaccination are solidarity, a high perception of risk and the low impact of conspiracy theories.

“Many people have been vaccinated to protect more vulnerable members of their family,” explains Lobera. Wagner agrees: “In the Spanish cultural context, intergenerational family ties are of great importance, as is close social contact in general. This was especially important now, in the summer, when many families get together.”

Spain had an advantage from the very outset

A high trust in health institutions – with acorresponding high acceptance of vaccines - and being linked to complex family and social networks means having “an advantage” from the very outset in comparison with other countries. We also have fewer conspiracy theories: “Traditionally, the anti-vaccine group in Spain is not as large as, for example, in Germany or France,” says Wagner.

However, Lobera warns that “we must not let our guard down: if the perception of risk decreases - which may happen precisely with the advance of vaccination -, the perception that by having been vaccinated you protect others, or if conspiracy theories increase, the results may change. The snowball effect also works the other way around.

For example, if the starting point is more rejection, having to encourage vaccination with gifts, this can trigger negative biases. “If I’m offered something in exchange, I hesitate; if the idea of making it compulsory is raised, I hesitate a bit more....,” Lobera remarks.

That a gift should act as a disincentive is not the only paradox when it comes to social behaviour, as is shown by another case: “The bad example of politicians jumping the queue may have created a 'valuable good' effect,” says Simón. “If they cheat to get it, then it must be good,” he continues.

Simón sees more complementary pro-vaccination factors. Having organised the vaccination strategy with clear priorities, communicated in a transparent way, has certainly made a scarce commodity more desirable. If, in addition, access is guaranteed in accordance with ethical principles of justice and equity, trust in the public health system is further strengthened.

The combination of non-compulsory vaccination and incentives has also helped: “Social life is so important to us that the cost of vaccination is considered low if in return we can go out for a drink with friends,” observes Simón. This would seem to create a quid pro quo with the state, which, as vaccination progresses - and cases of disease fall - would gradually remove restrictions.

Call effect: get vaccinated and tell others about it afterwards

Posting the moment of the injection on social networks “may seem banal, but perhaps it was not so banal,” adds the political scientist. It would have had a call effect: the more the people who upload their picture, the more other people want to upload theirs.

Helena Matute, an experimental psychologist at the University of Deusto, adds a practical issue to the list: organising a personalised appointment system, with a message that had to be answered in a short time.

“It’s worked very well,” says Matute, who explains a certain “opportunity” effect. People have felt that the system has taken care of them in a personal way, offering a service that had to be dealt with quickly, as otherwise attention had to move on to the next person in line.

“This has definitely been a logistical success for public health care,” Astrid Wagner agrees. “It has shown the importance of a public health system that is accessible to all in times of crisis. In addition, the appointment system has worked well. In other European countries, citizens had to register for vaccinations.

“From the beginning, vaccines were seen as the only way out of the crisis,” Wagner concludes. “And the experience of the crisis has been very strong in Spain.”

The greater the political turmoil, the fewer the people who get vaccinated

The high position on the world vaccination podium does not stand on its own. It is important to take care of it. Moreover,a crucial stage is drawing near: when the perception of risk decreases due to the increase in those vaccinated, and when all those willing to be vaccinated have been able to do so.

Last January, Lobera predicated that “concern [about reluctance] will reappear with forceafter the summer (...). Then the number of those who don’t wish to be vaccinated will be reflected and we will have to start a dialogue with them, because their health is also our health.”

A key factor will then be the attitude of political leaders. If their comments lead to a loss of trust in institutions, this could increase the rejection of vaccination. “Obviously, everything we say must be open to criticism in the scientific context,” explains Lobera. “Scientific debate is necessary, but we’ve got to be careful when criticism is made as part of a political game, to seek polarisation. The public notices this.”

Pablo Simón, from the Carlos III University, agrees and recalls that in countries with political leaders who have shown denialist attitudes, the rejection of vaccines has been high.

This article is also available in Spanish.