This is why the flu is more deadly in the elderly, but in Italy half do not vaccinate

All the fault of an Achilles' heel protein, which depletes the ability to shield against viruses. This is why the flu is more deadly for the elderly. This was discovered by a team of scientists who authored a new study published in the journal Pnas (Proceedings of the National Academy of Sciences). The experts observed that older people produce a glycosylated protein - called apoplipoprotein D (ApoD) -, which is involved in lipid metabolism and inflammation, at much higher levels than younger people. And this reduces the ability to resist viral infections, leading to worsening of the disease. Therefore, they point out, the elderly are more likely to suffer from severe influenza. Too bad that Italians' feeling for the flu vaccine continues to fail to blossom. On the eve of a new flu season, after last year's 16 million cases, it has emerged that in the last vaccination campaign only one Italian in five was 'protected', and in particular only just over half of the over-65s, the most fragile and exposed to the risks of the virus.

The findings of the new research can now be used to address this increased risk. The work is the result of an international collaboration led by scientists from China Agricultural University, the University of Nottingham, the Institute of Microbiology (Chinese Academy of Sciences), the Chinese National Institute for Viral Disease Control and Prevention and the University of Edinburgh. The authors investigated and found that ApoD production that becomes very high with age causes extensive tissue damage in the lungs during infection, reducing the protective antiviral response of type I interferon. 'Ageing is a major risk factor for influenza-related deaths,' notes Kin-Chow Chang of the School of Veterinary Medicine and Science at the University of Nottingham, co-author of the study. And it must also be taken into account that 'the world population is ageing at a rate unprecedented in human history, posing serious problems for health care and the economy,' he adds. 'We therefore need to find out why elderly patients often suffer more severely from influenza virus infections,' the researcher emphasises.

In the study, the team investigated this aspect and investigated the mechanisms underlying the increase in severity of influenza virus infection with age using an elderly mouse model and appropriate sections of donated human tissue. Thus, ApoD was identified as an age-related cellular factor that impairs activation of the immune system's antiviral response to influenza virus infection, causing extensive degradation of mitochondria (mitophagy), resulting in increased virus production and lung damage during infection. Mitochondria are essential for cellular energy production and the induction of protective interferons,' the authors point out, 'and ApoD is therefore a target for therapeutic intervention to protect against severe influenza virus infections in the elderly, which would have a significant impact on reducing morbidity and mortality in this age group. 'By inhibitory targeting of ApoD,' Chang concludes, 'there is now an exciting opportunity to therapeutically improve influenza severity' in this frail population segment.

Influenza, as has been said, can be risky for the most fragile patients, and in particular the elderly, and vaccinations are currently the most effective tool for defending oneself: for some years now, however, Italy has been experiencing a real flight from the vaccine. And this phenomenon also concerns the most fragile - the over-65s - since by now practically only one in two elderly people are vaccinated against influenza, with a decline that has been constant for several years: in the last 2024-2025 vaccination campaign - as reported to Il Sole 24 Ore by the Ministry of Health - the over-65s who immunised themselves against influenza fell to a meagre 52.5%, compared to 53.3% the year before and 56.7% in 2022-2023. Numbers are steadily decreasing and far from the 65.3% achieved at the height of the pandemic - in 2020-21 - and still far from the minimum target of 75% indicated by the WHO for this vaccination (the ideal would be 95%). On the other hand, vaccinations in the general population rose slightly to 19.6% (it was 18.9% the year before).