Anti-flu vaccination coverage in the elderly and the multiple deprivation index in Sardinia
The flu syndrome represents a serious public health problem and a significant source of direct and indirect costs arising from the implementation of measures of control and of case and disease complication management.
Infections with flu viruses cause an important epidemiological, social and economic impact in industrialised countries (1). Currently, according to the World Health Organisation (WHO), flu-related deaths can be estimated at between 250,000 and 500,000 worldwide. In Italy alone, each year from 5 to 8 million subjects are affected by flu syndrome with deaths estimated at approximately 8,000 (2).
Severe cases and complications of flu are more frequent in subjects over 65 years of age with underlying medical conditions, who are therefore exposed to a higher risk of infection and, consequently of hospitalisation and death (3 , 4). At present, the flu vaccine is the most effective tool to avoid flu illness and to reduce the related costs. In Italy, vaccination is offered actively and free of charge to all subjects aged 65 and over, in addition to the risk categories provided for in the 2017-2019 National Vaccine Prevention Plan.
Despite this important opportunity for prevention, the percentage of subjects vaccinated among people over the age of 65 is continuously falling and does not comply with the minimum desirable threshold of 75%; Sardinia shows a constantly decreasing trend (from 2009 to 2016 in fact, it went from a percentage of vaccination coverage of 61% to 40%), currently among the lowest in Italy.
To overcome the critical issues related to low vaccination rates in over 65s, a solution strategy could materialise through the planning of interventions to promote flu vaccination aimed at a precise group of subjects, taking into account the main socio-economic characteristics and of the education/information needs of the elderly population in order to increase their vaccination uptake.
Several international studies have also shown that socio-economic condition and a possible situation of deprivation play an important role in the failure to adhere to vaccination programs (5). Therefore various projects (CCM) have been launched to analyse the correlation between inequalities and low flu vaccination coverage for vulnerable groups such as the elderly, elaborating on the role of Socio-Economic Status (SES), considered one of the main social determinants of health status and of the ability of an individual to fully follow the indications for prevention. More precisely, a low SES is associated with low vaccination coverage in countries such as Spain, France and the United Kingdom. In Italy, the situation appears to be different, as some studies (6) have shown that flu vaccination is more widespread in elderly people with a lower socio-economic status (65%) than in those with a higher one (57%). However, it is necessary to underline that these results derive from sample surveys carried out through questionnaires not specific to this topic, which may have generated a differential response bias between subjects of different SES.
Against this backdrop, Sardinia has also taken part in a CCM project: " 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 flu ”, aimed at analysing the correlation between inequalities and coverage in the elderly with the objective of proposing strategies to promote vaccination tailored to the real needs of the population.
An analysis was carried out in the 8 macro-areas (ASSL) of Sardinia, prior to the scrutiny of the island’s census sections (application of SE deprivation indices in Sassari), the final objective of the Project. To better identify the main population subgroups not undertaking vaccination, the socio-economic summary indicators were used while taking into account the multidimensional aspects of social stratification, i.e. the socio-economic deprivation indices that allow identification of the link between socio-economic inequalities and health outcomes. Therefore, flu vaccination coverage was calculated and correlated with a multiple deprivation index (IDMS 2013) (7) on indices of income, employment, education, services, environment, crime and health. The eventual association was evaluated with simple linear regression.
In recent years (2013-2016) in Sardinia, there was a flu vaccination coverage of approximately 40%. The macro-area analysis shows, in the 2015-2016 season, a relationship subject to a ratio of inverse proportionality between anti-flu coverage and deprivation index (y = -12.36x + 50.74; R ^ 2 = 0.15) with the highest uptake in Ogliastra and the lowest in Cagliari.
In Sardinia, at macro level, the relationship between low adhesion to vaccination and socio-economic health status (SES) is confirmed. Since the results could be affected by changes in supply at the macro-level, regardless of the socio-economic determinants of the population, the study will continue with the analysis of the census sections of each homogeneous macro-area, in order to confirm the highlighted report and set down measures to promote vaccination.
In the identified sub-populations, the predictors of intention to avail of vaccination will also be investigated, taking into consideration: attitudes towards vaccination, influenza as an infectious pathology, and the perception of factors that prevent or facilitate vaccination. These data will be fundamental insofar as they will allow us to determine the informative needs of the elderly population and thus to tailor communication aimed at this group in order to increase uptake of all vaccinations.
Sources / Bibliography
- World Healt Organization. Influenza. Global Influenza Program (http://www..who.int/influenza/en/)
- Dati CNESPS – Istituto Superiore di Sanità.
- Paolo Bonanni, Mauro Ruggeri, Alessandro Rossi. Vaccinazione antinfluenzale: come incrementare le coperture vaccinali. Razionale, strategie e strumenti. Società Italiana di Medicina Generale. N° 4, Agosto 2012.
- Gasparini et al. Effectiveness of adjuvanted seasonal influenza vaccines (Inflexal V® and Fluad®) in preventing hospitalization for influenza and pneumonia in the elderly. Human Vaccines & Immunotherapeutics 2013; 9:1:150-158
- Peretti-Watel P, Raude J, Sagaon-Teyssier L, Constant A, Verger P, Beck F. Attitudes toward vaccination and the H1N1 vaccine: poor people’s unfounded fears or legitimate concerns of the elite? Social Science and Medicine, 2014; 109:10-18.
- Damiani G, Federico B, Visca M, Agostini F, Ricciardi W. The impact of socioeconomic level on influenza vaccination among Italian adults and elderly: A cross-sectional study. Preventive Medicine, 2007;45:373-379.
- Indice di Deprivazione Multipla della Sardegna (IDMS) 2013 – sardegnaprogrammazione – (http://www.sardegnaprogrammazione.it/documenti/35_84_20140213123944.pdf)