The vaccination race: a public health view

DISCLAIMER: All opinions in this column reflect the views of the author(s), not of EURACTIV Media network.

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Marathon runners say that the real difficulties, what they call “the wall”, appear between km 30 and 35. At this point, physical and mental exhaustion forces some runners to withdraw. We have reached this point with COVID-19. We must find the tools and the strength to keep on running. Finishing this race is critical for all of us. It is critical to the entire world.

Antoni Trilla, MD, PhD is an Epidemiologist at Hospital Clínic of Barcelona, Professor and Dean of Medical and Health Sciences School at the University of Barcelona, and Research Professor at ISGlobal.

By October 1st, the EU stands at a 63% level of full vaccination, meaning that 63% of the EU population has received a full course of vaccines, either one or two doses, depending on the vaccine used. By contrast, the UK stands at 70% and the USA at 55%. Among the most populated countries in the EU, Spain reaches the 77% level, followed by Italy (69%), France and Germany (65%) and Poland (51%).

Are these high statistics enough?

With the Delta variant of concern (VOC) dominating the field in the EU and elsewhere, we need more population to reach the immune status. The level of immunity is not equal to the level of vaccination: some people are immune because they have overcome COVID-19 or because they have a certain degree of cross-immunity against other coronaviruses. Others do not respond well enough to vaccines, especially the elderly and the immunosuppressed patients. Not all people can still get vaccinated (eg: children under 12 years of age). Finally, and pitifully, not all people agree to be vaccinated. Much work remains to be done to reach the so-called herd immunity.

The technical definition of group or herd immunity is that of an adequate level of immunity, able to keep the basic reproductive number (R0) of a disease below 1 in a specific population in the absence of other control measures. The Delta VOC is more transmissible than the original virus and than the Alpha VOC: its R0 ranges between 4 and 8.

The theoretical level of group immunity for Delta (calculated as 1- 1/R0) would lie down around the 85% level of a fully immunized population. Vaccinating 85% of the entire population, adding perhaps 5-10% more due to the likely absence of a good immune response in some individuals, is a very hard goal to achieve.

The key issue now that we are coming closer to the end of the race is how to reach that 85% or 90% of the vaccinated population. Why are there people still not vaccinated in Europe?

Three necessary but not sufficient conditions must always be met for a successful vaccination campaign: 1) to have safe and effective vaccines, 2) to have the ability to administer them quickly and in a handy way, and 3) that most of the population agree to get them.

In the EU we fulfil the first two quite well. We are also investing heavily in new vaccines research and development. We need safe and effective vaccines against current and likely VOC that could appear in the future. Vaccines that are also easy to store and deliver.

However, the third condition is now what worries us the most and the hardest to overcome. The theory explains that there are people radically opposed to vaccination (the deniers or “anti-vaxxers”), people who are reluctant to vaccination and are primarily concerned about the safety of vaccines and their possible adverse effects (the “vaccine-hesitant”), and a third group who do not seem to be interested in vaccination, which we classify as “apathetic” or unconcerned.

Some business and marketing theories show that communication strategies must necessarily be different to address vaccine hesitancy and vaccine apathy. In the case of hesitant people, whose response is emotional and cognitive but with a high involvement, adequate technical and scientific information is required. We need to establish a useful dialogue: listen to them, answer their questions and address their concerns, showing empathy towards them. In the case of the apathetic, indifference is the norm.

They do not get involved and do not even make the psychological effort to worry about the disease or the vaccine. Apathetic people can be persuaded by simple, quick, and emotional arguments. New messages are conveyed by unusual, non-formal, channels. The source of the communication may be more important for them than the evidence or arguments used. These sources can be people they know, have high regard for, and/or have provided them with good information in the past. They should be people who are relatively similar to the group they are addressing.

For a 25-year-old apathetic unvaccinated citizen, a famous and respected sports star or a successful artist is far better than an expert scientist or physician. Better use Instagram or Facebook than newspapers, radio or television for reaching these apathetic people.

Identifying the best channels and messages to reach those who still need convincing may be the single most effective action to increase our vaccination rate.

It is likely that in the future we will live with COVID-19 in an endemic situation. There will be infections and sick people, some of them with severe forms that will need to be admitted in a hospital, and also deaths, but hopefully in low and manageable numbers, as happens and have happened with many other infectious diseases (pneumonia, diphtheria, measles).

Vaccines are not perfect, but they are by far the best option, and together with new treatments they are our tools to get out of this nightmare. We must continue to inform people and persuade them to be vaccinated. It will get harder and harder, but we can do it. We are only a few kilometres away from the finish line.

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