Online Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5415833/

Systematic review

Background

Influenza is a frequent cause of exacerbations of chronic obstructive pulmonary disease (COPD). Exacerbations are associated with worsening of the airflow obstruction, hospitalization, reduced quality of life, disease progression, death, and ultimately, substantial healthcare-related costs. Despite longstanding recommendations to vaccinate vulnerable high-risk groups against seasonal influenza, including patients with COPD, vaccination rates remain sub-optimal in this population.

Methods

We conducted a systematic review to summarize current evidence from randomized controlled trials (RCTs) and observational studies on the immunogenicity, safety, efficacy, and effectiveness of seasonal influenza vaccination in patients with COPD. The selection of relevant articles was based on a three-step selection procedure according to predefined inclusion and exclusion criteria. The search yielded 650 unique hits of which 48 eligible articles were screened in full-text.

Results

Seventeen articles describing 13 different studies were found to be pertinent to this review. Results of four RCTs and one observational study demonstrate that seasonal influenza vaccination is immunogenic in patients with COPD. Two studies assessed the occurrence of COPD exacerbations 14 days after influenza vaccination and found no evidence of an increased risk of exacerbation. Three RCTs showed no significant difference in the occurrence of systemic effects between groups receiving influenza vaccine or placebo. Six out of seven studies on vaccine efficacy or effectiveness indicated long-term benefits of seasonal influenza vaccination, such as reduced number of exacerbations, reduced hospitalizations and outpatient visits, and decreased all-cause and respiratory mortality.

Conclusions

Additional large and well-designed observational studies would contribute to understanding the impact of disease severity and patient characteristics on the response to influenza vaccination. Overall, the evidence supports a positive benefit-risk ratio for seasonal influenza vaccination in patients with COPD and supports current vaccination recommendations in this population.

–          This article was published in 2017 and its focus was to find out the effectiveness of seasonal influenza vaccination in patients with COPD.

–          This systemic review included 4 RCTs, 2 prospective cohort studies, 5 retrospective cohort studies and 2-self controlled case studies with a total population size of 174,145 patients.

–          These studies were performed across different influenza seasons in Australia, Taiwan, India, Spain, UK and US.

–          In this systemic review, they excluded studies that included patients with a mix of pulmonary diseases and if results were not presented for separately for COPD.

–          Also excluded studies without a control group receiving placebo.

Results:

–          No evidence of an increased risk of exacerbation up to 14 days post- vaccination was shown in those pts who received the vaccine.

–          Spirometry did not show significant changes after vaccination when compared to the non-vaccinated group.

–          Two of the 4 RTC’s reported local symptoms occurring where the vaccine was given. Those symptoms were pain at the site of injection, itching and swelling. All of the reported cases were non-life threatening.

–          When it came to constitutional symptoms, there was no significant difference between the group that received the vaccine vs the placebo group.

–          One prospective study reported that after one year of follow-up, vaccinated patients experienced significantly less episodes of influenza-related acute respiratory than unvaccinated patients, (1/63 patients in those who got the vaccine vs 46/ 63 patients in those who didn’t).

–          Vaccinated patients also had significantly fewer outpatient visits (2/63 in those who did receive the vaccine vs 12/63 in those who didn’t receive the vaccine.)

–          In the study that was conducted in Spain, they found no significant difference between those who received the vaccine and those who didn’t in mortality rate.

–          Retrospective study in Taiwan which had more than 25,000 pts, concluded that seasonal influenza vaccination in elderly pts with COPD, significantly reduced exacerbation than those who didn’t receive the vaccine.

Conclusion: This systemic review presented overwhelming evidence on the effectiveness of seasonal influenza vaccination in patients with COPD. Although receiving the seasonal influenze vaccine can lead to some additional side effects such as, itching, pain and swelling in the site of the injection, the benefits here outweigh the risks and its also recommended by most international and national health organizations to receive such vaccination in those who suffer from COPD.

–          I chose this article because it has the highest level of evidence being a systematic review. It’s also very recent, it was published in 2017, which makes it a more reliable source. It also has a big population size of more than 174,145 pts from different countries.