Elsevier

Vaccine

Volume 29, Issue 37, 26 August 2011, Pages 6366-6368
Vaccine

Coverage and side effects of influenza A(H1N1) 2009 monovalent vaccine among primary health care workers

https://doi.org/10.1016/j.vaccine.2011.04.117Get rights and content

Abstract

In June 2009, WHO declared the maximum phase alert against H1N1 pandemic flu. Health care workers (HCWs) are considered a strategic target for prevention of the occurrence of H1N1 influenza since they had the greatest risk of acquiring infection. The objectives of our study were (1) identifying the uptake of influenza A(H1N1) 2009 monovalent vaccine by primary health care workers in the southern part of Cordoba, and (2) reporting of the adverse events occurred after vaccination. We followed 240 HCWs in 12 primary health care centres at southern part of Cordoba for vaccine uptake and the occurrence of adverse events. The coverage rate with H1N1 vaccine was 20.5% which was lower compared to seasonal influenza vaccination rate 44.2% in 2009. Males had higher H1N1 vaccination rate compared to females with no significant difference. Senior HCWs complied more with seasonal influenza vaccine while this finding was not consistent with H1N1 vaccination. Multivariate analysis showed that the only independent variable that affected H1N1 vaccine was the compliance to the seasonal flu vaccine in the past three years with OR 5.1 and 95% CI (2.4–10.8). Adverse events occurred among 26.5% of those who complied with H1N1 vaccination. Those were local pain, irritation and induration at site of injection (38.5%), fever (15.4%), fever cough and rhinorrhea (15.4%) generalized pain and lumber pains (23.1%). The low vaccination rate in this study is consistent with previous studies done in many parts of the world and in Spain. Further studies should be done to explore the factors that hindered the uptake and resistance of HCWs to vaccination to H1N1 vaccine.

Introduction

In late April 2009, the World Health Organization (WHO) announced the emergence of a novel influenza A virus. This particular H1N1 strain has not been circulated previously in humans and required WHO to raise the pandemic alert to phase 5 less than 1 week after declaring phase 3. On 11 June 2009, WHO declared a phase 6 influenza pandemic alert, which is the maximum alert level [1].

Health care workers (HCWs) are a strategic target for pandemic influenza A(H1N1) prevention such as vaccination and frequent hand-washing, since they are at higher risk themselves of contracting influenza, can place their patients at risk and are critical for a functioning health care system [2]. In the United States, influenza A(H1N1) vaccine was made mandatory for hospital employees [3]. Recent survey on Italian HCWs showed that a high percentage of them did not realise that vaccination against influenza A(H1N1) virus is a fundamental means of prevention [4].

The overall vaccination coverage by seasonal flu vaccination in a survey in Spanish university hospital varied between 16 and 40% along three consecutive campaigns [5]. The vaccination of HCWs plays an important part in prevention programs aimed at reducing influenza-related morbidity and mortality among high-risk patients [6].

The Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices [6], [7] (ACIP) has recommended influenza A(H1N1) vaccine for health care workers and considered HCWs among initial target groups for vaccination.

The objectives of our study were identifying the uptake of influenza A(H1N1) 2009 monovalent vaccine by primary health care workers in the southern part of Cordoba and exploring the correlation between H1N1 vaccine uptake and seasonal flu vaccination. Also this study aimed at reporting of the adverse events occurred after vaccination by those who complied to the vaccine uptake.

Section snippets

Methodology

All HCWs of 12 primary health care (PHC) centres in South Cordoba Health District were invited to participate in the study. South Cordoba Health District offers PHC to the population residing in the Southern Area of the Province of Cordoba (Andalusia, Spain). This PHC District has 45 villages and could serve over 300,000 persons.

Of 327 HCWs of the 12 PHC centres, 240 accepted to participate in the study, with participation rate of 73.4%. The data were collected from HCWs 3 weeks after starting

Statistical methods

First, the following descriptive analysis was done: frequency, percent, mean, standard deviation. The statistical tests used in this paper were chi-square and chi-square for trend, odds ratios and confidence intervals were also calculated. A logistic regression model was done to investigate the independent factors relating to the uptake of the H1N1 vaccine. Level of significance was set at P < 0.05. All data variables were encoded and computerized. Data entry and statistical analysis were

Results

This study included 240 HCWs working in 12 primary health care centres at Southern Cordoba Health District. The mean age of the studied health care workers was 46.8 ± 7.8 years (range 25–65 years). Females constituted 56.7% of the studied sample. The coverage by seasonal flu vaccine was 43.3%, 43.8% and 44.2% in the years 2007, 2008 and 2009 respectively. These coverage rates were higher compared to the coverage by H1N1 vaccine in response to the pandemic alert which was 49 cases only (20.5%).

The

Compliance and adverse events

The total number of subjects who complied with three doses of seasonal flu vaccine and H1N1 vaccine was 34 HCWs (14.1%). Among those complaint subjects 13 subjects (38.2%) reported the occurrence of adverse events. The reporting of adverse events among compliant subjects to three doses of seasonal flu vaccine was higher in males compared to females and the difference is significant statistically.

A logistic regression model to see the effect of age, gender (male gender) and vaccination with

Discussion

Health care workers are at the frontline for caring of patients with pandemic influenza. Among the recommendations of WHO in good practice and preparedness of HCW to pandemic flu is the adherence of health care workers to vaccination [8]. However several studies have reported resistance of intake of H1N1 vaccine in health care workers.

In a university hospital in Madrid, Spain (12 de Octubre) the coverage rate for seasonal flu vaccine in health care workers was 49.7% which is comparable to our

References (12)

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