Anti-flu vaccination and over the 65s: the real needs of the elderly population

According to WHO estimates, seasonal flu epidemics occur every year in our latitudes during the winter season, affecting 5 to 15% of the world population, or 350 million to 1 billion people, and resulting in 250,000-500,000 deaths each year. Three to five million serious cases require hospitalisation of at-risk subjects, including elderly people with chronic diseases. In Italy alone, it is estimated that annually influenza-like syndrome (ILI) affects from 5 to 8 million people, including many over the age of 65.

In Public Health the prevention of seasonal flu is of prime importance in order to reduce the clinical and economic impact of the disease. To date, vaccination is the most effective tool available for this purpose. The flu vaccine, in fact, embodies the best preventive strategy to reduce the epidemiological, clinical and economic impact of influenza. Among the applicable strategies, the most effective is unquestionably protection of the population groups most at risk, in particular of the elderly cohort. Even though this important prevention tool is offered actively and free-of-charge to the elderly, considered the category most at risk of developing complications, and despite the ample demonstrations of the safety and efficacy of the flu vaccine, uptake does not reach the recommended minimum values.

In Italy, the desirable vaccination coverage of 75% in the over 65s has never been reached and in the last 15 years the percentages have always fluctuated in a range between 50 and 70%.

Fig.1 Flu vaccination uptake in the over 65s
Fig.1 Flu vaccination uptake in the over 65s

Maximum coverage was achieved in the 2005-2006 season (68.3%); subsequently there was a significant decrease in uptake with the minimum level recorded in the 2014-2015 season (48.6%), and during the 2016-2017 season the coverage recorded was 52.6%, in recovery compared to the previous year (49.6%). As shown in Figure 1, the aforementioned coverage rates vary haphazardly from region to region. Sardinia is unfortunately among the regions with the lowest vaccination uptake together with the autonomous province of Bolzano.

At the same time, it must be emphasised that in Sardinia, as in the rest of Italy and in Europe, a further rise in the average age of the population is expected, above all in the proportion of people over 65. This demographic change will cause changes in health needs which, as regards the fight against preventable infectious diseases such as influenza, will have to take into account the characteristics of the elderly population.

Fig.2 Struttura della popolazione sarda dal 2002 al 2017
Fig.2 Struttura della popolazione sarda dal 2002 al 2017

As seen in Fig.2, the elderly population (over 65s) in the Region of Sardinia increased from 16.1% in 2002 to 22.7% in 2017. In such a context, not only is the increased number of elderly people important, but also their state of health, which explains why the increase in life expectancy will always entail new challenges for Public Health. Demographic ageing and the long survival of patients with chronic-degenerative diseases will lead to an increase in the proportion of the frail elderly population (where ‘frail’ means having a reduced capacity to respond quantitatively and qualitatively to the environmental stimuli associated with a loss of functional autonomy). This will correspond to an increase in demand for healthcare and a greater burden on resources.

In this regard, it should be remembered that population ageing refers to the age-dependent biological state characterised by a reduced resistance to stress, secondary to the cumulative decline of several physiological systems and related to multi-pathologies, disability, immunosenescence, risk of institutionalisation and mortality. As such, preventive actions for a "healthy ageing" will become fundamental. Of these preventive actions, the prophylaxis of infectious diseases such as the flu syndrome is among the main activities.

Furthermore, it is important to underline the fact that nowadays important and significant elements hypothesise and prove that the vaccination of over 65s can also limit, to some extent, excess mortality in the winter season. Indeed, significant complications can occur following the flu: bacterial superinfections affecting the respiratory system (primary and secondary pneumonia) and the ear (otitis, sinusitis), complications affecting the cardiovascular system (myocarditis) and nervous system, as well as the aggravation of pre-existing diseases (activation of atheromatous plaque, with risk of heart attack or stroke) with sometimes fatal outcomes.

To overcome the critical issues related to low vaccination uptake in subjects over the age of 65, a resolutive strategy could materialise through the study, analysis and programming of interventions to promote flu vaccination, specifically targeting cohorts at increased risk such as the over 65s, while taking into account the main socio-economic characteristics and education/information needs of the elderly population in order to increase their vaccination uptake.

For these reasons, Sardinia has taken part in a Project from the National Centre for the Prevention and Control of Infectious Diseases (CCM) funded by the Ministry of Health: "Flu vaccination in the elderly. How the use of deprivation indices, the main socio-economic characteristics and information/education needs can contribute to improving vaccination coverage and consequently to reducing access to the Accident and Emergency Departments (DEAs) and hospital admissions linked to influenza ", highlighting an important correlation between inequalities, understood as situations of disadvantage of the elderly population in Sardinia, and anti-influenza coverage. This trend, already noted at the macro-area level and described in the article: Anti-influenza vaccination coverage in the elderly and the multiple deprivation index in Sardinia, was more specifically studied within the homogeneous areas and in particular in the context of the elderly population of Sassari (Fig. 3), with the aim of proposing strategies to promote vaccination based on the real needs of the population.

Fig.3 Area of ​​study: representation of census areas by Deprivation Index
Fig.3 Area of ​​study: representation of census areas by Deprivation Index

The project involved 10 Operative Units (OU) distributed throughout the national territory. Using data from the 2011 census, the socio-economic health deprivation rates (which allowed for the division of the population into 5 groups of deprivation: very deprived, quite deprived, not deprived, quite wealthy and very waelthy) were built on the basis of a specific methodology, standardised and validated in other studies, in order to analyse the relationships between socio-economic inequalities and aspects associated with health, prevention and adherence to vaccination campaigns. A complex selection process led to the identification of a set of different variables for each area, capable of expressing the inequalities related to health status. The results of this study, which will be published shortly, show how the Socioeconomic Health Deprivation Indexes play an important role in health choices and allow identification of the characteristics of the main sub-groups of the population who refuse vaccination. The future perspectives of the project are aimed at understanding the reasons for the failure to adhere to the influenza vaccination using strategies adapted to the elderly. Among these, the promotion of the flu vaccination campaign certainly poses a significant challenge for the achievement of objectives such as the reduction of the individual risk of disease, hospitalisation and death, and the reduction of costs associated with morbidity and mortality. Therefore, this challenge must push all healthcare professionals towards a renewed commitment to promoting vaccination by informing the population about the real danger represented by the lack of adherence to the seasonal vaccination offer.

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