2012 June - Pneumococcal vaccine and influenza vaccine in COPD patients
Dr. Chun-Wai TONG; Department of Medicine, Pamela Youde Nethersole Eastern Hospital
Background:
COPD is a common disease in the world and causing significant mortalities and morbidities. As recommended by various international authorities, vaccination to both seasonal influenza and pneumococcal should be integral part of COPD management. The literature and international guidelines on the use of seasonal influenza and pneumococcal vaccines were reviewed in this dissertation. In Hong Kong, Centre of Health Protection is recommending that patients with chronic medical illness, such as COPD, should receive seasonal influenza and pneumococcal vaccines. However local data on the efficacies of the vaccines and the effectiveness of the vaccinations program are lacking.
Aims:
1. To investigate the effectiveness of the vaccination program in a local center and provide data on the efficacy of seasonal influenza vaccine and pneumococcal vaccine in reducing exacerbation-related hospitalization rate in patients with COPD (the COPD-Vaccination Study).
2. Subsequent to analyzing the results of the COPD-Vaccination Study, to survey the views and practice of medical staff in the Department of Medicine, PYNEH with regard to seasonal influenza vaccine and pneumococcal vaccine.
Methodology:
1. COPD-Vaccination Study: Design: Retrospective, single centre cohort study. List of COPD patients, who attended either outpatients clinics of Hong Kong East Cluster or admission to PYNEH during the period of 1 April 2009 to 31 March 2010, were retrieved with Clinical Data Analysis and Reporting System (CDARS) with the following ICD-CM9 codes: 491.20, 491.21, 492.0, 492.8, 493.20, 493.21 and 496. Patients who received pneumococcal vaccines, seasonal influenza vaccines or both during the same period were followed-up for 1 year post-vaccination to record clinical events which were then compared with a cohort of age and sex matched COPD patients who did not receive any vaccines in the same period.
2. The Survey: A survey on the views and practice with regard to seasonal influenza vaccine and pneumococcal vaccine of medical staff in the Department of Medicine, PYNEH was conducted in April 2012 using a questionnaire attached in the Appendix (the Survey). A convenience sample of medical staff of the Department of Medicine, PYNEH was surveyed over a 3-day period in April 2012. The questionnaires were filled by the staff themselves and collected within the same day.
Outcomes measurements:
1. The COPD-Vaccination study: Primary outcomes: Number of COPD exacerbation-related admissions. Secondary outcomes: 1) COPD-related outcomes: Number of COPD exacerbations in 1 year; number of severe COPD exacerbations as defined by requirement of ICU admission or institution of invasive/noninvasive ventilatory support; time from day of vaccination to first COPD exacerbation; 2) Infection-related and other medical illness-related outcomes: number of admission from any cause; number of documented febrile illness episodes; documented influenza infection; time to death.
2. The Survey: An 11-question questionnaire was distributed among medical staff which included questions regarding questions concerning the compositions of the seasonal influenza and pneumococcal vaccines used in our department. Their view and practice in advising eligible patients to receive the vaccines were also assessed.
Results:
1. The COPD-Vaccination study: 141 of 1122 eligible COPD patients (12.6%) received both seasonal influenza vaccine and pneumococcal, while 34 received seasonal influenza vaccine alone and 36 received pneumococcal vaccine alone in the study period. Compared with the control group, dual vaccination was associated with non-significant reduction in number of COPD exacerbation-related hospitalization (-0.06 admission/year, p=0.76). There were also similar reduction in the numbers of exacerbation (-0.13 exacerbation/year, p0.55), admission due to medical illness (-0.12 admission/year, p=0.64), and hospital length-of-stay (-2.92 day/years, p=0.4) in the year following vaccination in the dual vaccine group. In those who died or developed COPD exacerbation during the study period, Kaplan-Meier analysis demonstrated non-significant delay in time-to-patients’ death, but not in the time-to-first exacerbation.
2. The Survey: A total of 39 out of 45 questionnaires distributed amongst medical staff of the department were returned for analysis. The majority (87.2%) of responders did not receive seasonal influenza vaccine in the current year (2011/12 vaccination period). A significant portion of the medical staff surveyed was not aware of the composition of the seasonal influenza vaccine (51.3%) and pneumococcal vaccine (76.9%) currently in use. Although most of them believed that seasonal influenza vaccine (69.2%) and pneumococcal vaccine (79.5%) are “Very effective” or “Quite effective” in preventing morbidities and mortality associated with influenza and pneumococcal infection, they did not regularly recommended vaccinations to eligible patients.
Conclusion
In the cohort of COPD patients studied, no statistical significant benefits of seasonal influenza vaccine, pneumococcal vaccine and dual vaccines on reducing COPD exacerbation-related hospitalization were found. The vaccination program was also found to be not effective and with overall very low vaccination rates in the eligible patients. This could have been related to the finding that medical staff had knowledge gaps with regard to seasonal influenza and pneumococcal vaccines, and most of them did not actively recommend vaccinations to eligible patients.
