Coverage and predictors of vaccination against 2009 pandemic H1N1 influenza in Madrid, Spain
Introduction
With the emergence of the new pandemic influenza strain (H1N1) at the end of April 2009, an international public health emergency was declared. This was recently considered to have finished [1]. From the emergence of the virus until June 27, 2010, at least 18 449 people have died from the disease in 214 countries [2]. In Spain, 271 deaths from H1N1 influenza were registered in 2009, i.e., 0.21 deaths per 1000 people affected [3].
Vaccination against influenza is clearly an effective measure [4]. Consequently, when the World Health Organization (WHO) declared phase 6 of the pandemic in early June 2009, it encouraged the health authorities to define a strategy with a vaccination created specifically for the circulating strain, as the virus was new and the population was not immune to it [5]. This vaccination campaign was launched along with the yearly seasonal flu campaign, and its main objectives were to directly mitigate transmission by recommending the vaccination for high-risk groups, ensure the general capacity to respond to the pandemic, and to protect the integrity of critical infrastructures [6].
The H1N1 influenza vaccination campaign began on November 16, 2009 in all Spanish Autonomous Communities. Following the indications of the Interterritorial Council of the National Health System at its meeting on October 22, 2009, vaccination was recommended for the following population groups: social and health workers, people working in essential services, pregnant women, and anyone aged over 6 months whose health status placed them at high risk of complications arising from infection by H1N1 influenza. The recommendations for people with chronic conditions were the same as for seasonal influenza, except for the inclusion of morbid obesity and chronic anemia [7].
In Spain, three vaccines—Focetria®, Pandemrix®, and Panenza®—have been approved for strain A/California/7/2009 (H1N1). The vaccines come in different presentations and are intended for different population groups; Focetria® for children (6 months to 17 years) and elderly (>60 years), Pandemrix® for adults (18–60 years), and Panenza® for pregnant women [7]. The Ministry of Health and Social Policy purchased approximately 13 million doses. The vaccine was distributed free to public and private vaccination centers, although it was administered mainly at primary care centers of the National Health System. The initially estimated target population in the Autonomous Community of Madrid comprised 1,225,443 people [7].
Coverage data for those population groups for whom vaccination was indicated due to chronic conditions have not yet been published in Spain. Although some studies show theoretical vaccination uptake based on telephone surveys or self-administered surveys [8], [9], [10], [11], very few studies have calculated coverage by analyzing individual vaccination registers [12], [13].
Completion of nominal registers by the health care professionals who administered the vaccine means that data on vaccination can be linked with the clinical information recorded in the primary care clinical history, thus making it possible to know vaccination coverage in specific risk groups in the Autonomous Community of Madrid and to analyze factors associated with vaccination (predictors).
To ascertain the coverage in the Autonomous Community of Madrid of vaccination against pandemic influenza in individuals aged over 6 months for whom vaccination is indicated due to a chronic health condition. To analyze factors associated with uptake of the influenza vaccine.
Section snippets
Materials and methods
Ours was a population-based cross-sectional study. The study sample included all people aged over 6 months of age for whom vaccination against H1N1 influenza was indicated due to chronic health conditions during the 2009/2010 campaign [7]. The population was registered in the public health system of the Autonomous Community of Madrid and, consequently, in the medical card database. On June 30, 2009, the population aged over 6 months stood at 6,366,490 people.
The information sources were as
Study population
The total number of people selected with indication for vaccination due to chronic conditions was 1,114,632 (men, 49.3%; women, 50.7%); mean age 54.2 years (SD 24.9 years). Immigrants accounted for 8.2% (90,868 people) of the population (Table 2). Of the indications for vaccination, the most common was asthma (30.3%) followed by diabetes (26.9%). The third most common indication varied with sex: for men it was other cardiovascular diseases and for women it was neuromuscular diseases (Table 2).
Discussion
In the present study, vaccination coverage was calculated taking as the data source nominal vaccination registers in public and private centers and diagnoses registered in the electronic clinical histories in primary health care facilities of the Autonomous Community of Madrid. The latter source enabled us to calculate coverage for each indication due to chronic conditions.
The rate of 14.6% reached for those people with an indication due to a risk condition suggests that coverage was very low,
Acknowledgment
This manuscript was translated to English using funds from the research project FIS PS09/01609 (Fondo de Investigaciones Sanitarias-Health Research Fund) from the Carlos III Institute of Public Health.
Contributors: C.R.R.—Conception and design of the study, analysis and interpretation of data, and drafting the article or revising it critically for important intellectual content. M.D.E.—Acquisition of data, analysis and interpretation of data AND revising it critically for important intellectual
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