Flu or Covid: why saying ‘this vaccine isn’t for you’ can convince the sceptics

Autumn 2026 has officially begun and, with the arrival of October, the public health sector is starting to prepare for the campaign to protect citizens from seasonal flu and, perhaps, to try to increase vaccination coverage rates against Covid-19, which is still circulating and, in some European countries, is causing fairly significant waves of infection. Despite the more than 2,700 deaths per year from influenza and the many hospitalisations of those with co-infections from various respiratory viruses, there is a rubber wall to overcome, made up of indifference, vaccine fatigue, difficulties in accessing vaccines and a latent infodemic that fills the information gaps. But will the usual appeals, with their classic, universal messages such as ‘let’s all get vaccinated!’, be enough to mobilise the public? An idea for breaking the deadlock comes from an unexpected lesson in consumer psychology from Harvard University and its school of public health.

A recent study published in the October issue of the Journal of Consumer Research and conducted by researchers at Harvard University analysed the impact of persuasive messages through eight field experiments and tracking platforms. One example involved measuring reactions to these two statements: “If you like strong coffee, this is the coffee for you”, “If you don’t like strong coffee, this isn’t the coffee for you”. Intuition would lead anyone to choose the first option. Yet the research shows that dissuasive framing generates significantly higher engagement and a greater propensity to adopt the product amongst the target audience.

According to the researchers, when a message explicitly states who it is not intended for, it sends a strong and immediate signal: this content is tailor-made for a specific audience. For those who recognise themselves in that profile, the message instantly becomes more relevant, authoritative and persuasive. Health messages are almost never universal. For example, the government’s recommendations for the 2026–2027 season clearly explain that flu vaccinations and Covid-19 booster jabs are recommended and offered free of charge to well-defined groups: those aged over 60, people who are vulnerable or have chronic conditions, pregnant women, children aged between 6 months and 6 years, residents of care homes, and healthcare or public service staff. Yet communication campaigns continue to address ‘everyone’, with the underlying hope of boosting vaccination rates by including coverage for those not primarily at risk.

This, however, can have two adverse effects: on the one hand, desensitisation amongst the priority target groups, with older people or vulnerable individuals who, in many cases, perceive the appeal as general bureaucratic ‘background noise’ rather than a life-saving recommendation tailored precisely to their health. And, on the other hand, the reaction of those outside the target group: a large proportion of the young and healthy population rejects the appeal (“It’s just the flu” or “I’ve already had three Covid jabs”…), perhaps fuelling scepticism and controversial narratives on social media. As revealed by various studies, in fact, when the volume of official information decreases or becomes too general, disinformation – which can be highly compelling – immediately fills the gaps, coming to account for over 60–70 per cent of high-engagement posts with its discouraging narratives.

So, to rekindle interest and genuinely protect at-risk groups from the autumn mix of respiratory viruses (flu, Covid-19, RSV), public communication could try applying the strategy suggested by Harvard: stating who is to be excluded. Here, then, is how official slogans might be reworded: “If you are under 60 and have no chronic conditions, this vaccine is NOT intended for you.” Or: “If you think the flu is just a two-day nuisance and you don’t come into contact with vulnerable people, you can ignore this message.” The adoption of ‘dissuasive framing’ in healthcare could yield three immediate benefits: making vaccines perceived as a personalised and essential protective measure; countering misinformation; and facilitating the co-administration of the flu vaccine and Covid booster in a single session for those at risk. As the Harvard research recommends, to convince the right people, one must have the courage to exclude those who are not currently a priority.