Chest: Flu Vaccine Reduces Severe Outcomes Among Hospitalized Patients With COPD

Photo Credit - CDC PHIL



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Despite a history of less-than-perfect performance (see Eurosurveillance: Low 2016/17 Vaccine Effectiveness (VE) Among Elderly Hospitalized H3N2 Cases) - receipt of the flu vaccine has been shown (repeatedly) to reduce the morbidity and mortality associated with our annual influenza season. 

For most healthy adults, that might only mean a reduced risk of infection, or fewer`sick days' when the vaccine fails to protect completely. But for those at higher risk of complications, it could be lifesaving.

Increasingly influenza and other respiratory infections have been linked to the exacerbation of certain chronic health conditions, including coronary artery disease. 

NFID: Chronic Health Problems & The Flu

Eur. Resp.J.: Influenza & Pneumonia Infections Increase Risk Of Heart Attack and Stroke

NEJM: Acute Myocardial Infarction After Laboratory-Confirmed Influenza Infection

Int. Med. J.: Triggering Of Acute M.I. By Respiratory Infection

It stands to reason, that if you can reduce the incidence (or at least the severity) of influenza infection in the general population using the flu vaccine, you ought to be able to reduce the number of deaths among high risk individuals.

And over the past few years, we've seen evidence that the flu shot does reduce the risk of bad outcomes in high risk patients. A few recent examples include: 

• Last month, a study appearing  the American Heart Association's journal Circulation, found a substantial reduction in deaths among heart failure patients who received a yearly flu shot (see AHA: Study Shows Flu Shots Reduce Deaths From Heart Failure).
• A year ago, in CMAJ Research: Repeated Flu Vaccinations Reduce Severity of Illness In Elderly, a study found that repeated yearly flu vaccinations reduce the severity of illness in the elderly - usually the hardest hit segment of the population - even when it fails to prevent infection. 
• In 2017 we saw a study published in the CID Journal: Flu Vaccine Reduces Severe Outcomes in Hospitalized Patients, that cited being vaccinated was associated with less severe illness, lower mortality, and shorter hospitalization stays.

Today we've another study - this time on the effects of vaccination on hospitalized patients with COPD (Chronic Obstructive Pulmonary Disease) - that finds a substantial benefit from the flu vaccine. 

Researchers found a lower mortality rate, less critical illness, and a 38% reduction in influenza-related hospitalizations in vaccinated vs unvaccinated individuals.

Despite long-standing recommendations by the medical community, and a growing weight of evidence, only 50% to 60% of patients with COPD are vaccinated each year against seasonal influenza.

Effectiveness of Influenza Vaccination on Hospitalizations and Risk Factors for Severe Outcomes in Hospitalized Patients With COPD

Sunita Mulpuru, MD; Li Li, MSc; Lingyun Ye, MSc; Todd Hatchette, MD; Melissa K. Andrew, MD, PhD; Ardith Ambrose, RN; Guy Boivin, MD; William Bowie, MD; Ayman Chit, MBiotech; Gael Dos Santos, PhD; May ElSherif, MD; Karen Green, MSc; Francois Haguinet, MSc; Scott A. Halperin, MD; Barbara Ibarguchi, MSc; Jennie Johnstone, MD; Kevin Katz, MD; Joanne M. Langley, MD; Jason LeBlanc, PhD; Mark Loeb, MD; Donna MacKinnon-Cameron, MMath; Anne McCarthy, MD; Janet E. McElhaney, MD; Allison McGeer, MD; Jeff Powis, MD; David Richardson, MD; Makeda Semret, MD; Vivek Shinde, MD, MPH; Daniel Smyth, MD; Sylvie Trottier, MD; Louis Valiquette, MD; Duncan Webster, MD; Shelly A. McNeil, MD, FIDSA; on behalf of the Serious Outcomes Surveillance
(SOS) Network of the Canadian Immunization Research Network (CIRN) *

Chest
Volume 155, Issue 1, January 2019, Pages 69-78

Background

The effectiveness of influenza vaccination in reducing influenza-related hospitalizations among patients with COPD is not well described, and influenza vaccination uptake remains suboptimal.

Methods

Data were analyzed from a national, prospective, multicenter cohort study including patients with COPD, hospitalized with any acute respiratory illness or exacerbation between 2011 and 2015. All patients underwent nasopharyngeal swab screening with polymerase chain reaction (PCR) testing for influenza. The primary outcome was an influenza-related hospitalization. We identified influenza-positive cases and negative control subjects and used multivariable logistic regression with a standard test-negative design to estimate the vaccine effectiveness for preventing influenza-related hospitalizations.

Results

Among 4,755 hospitalized patients with COPD, 4,198 (88.3%) patients with known vaccination status were analyzed. The adjusted analysis showed a 38% reduction in influenza-related hospitalizations in vaccinated vs unvaccinated individuals. Influenza-positive patients (n = 1,833 [38.5%]) experienced higher crude mortality (9.7% vs 7.9%; P = .047) and critical illness (17.2% vs 12.1%; P < .001) compared with influenza-negative patients. Risk factors for mortality in influenza-positive patients included age > 75 years (OR, 3.7 [95% CI, 0.4-30.3]), cardiac comorbidity (OR, 2.0 [95% CI, 1.3-3.2]), residence in long-term care (OR, 2.6 [95% CI, 1.5-4.5]), and home oxygen use (OR, 2.9 [95% CI, 1.6-5.1]).

Conclusions

Influenza vaccination significantly reduced influenza-related hospitalization among patients with COPD. Initiatives to increase vaccination uptake and early use of antiviral agents among patients with COPD could reduce influenza-related hospitalization and critical illness and improve health-care costs in this vulnerable population.

Trial Registry

ClinicalTrials.govNo.:NCT01517191; URL www.clinicaltrials.gov

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Although the flu vaccine is far from perfect - it does provide an extra layer of protection - very much like wearing a seat belt in your automobile.  It won't guarantee that you'll walk away from a bad wreck, but it certainly increases your chances. 

But even if you do get the flu shot -  given its moderate effectiveness, and the number of non-influenza viruses out there - it is also important to consistently practicing good flu hygiene (covering coughs, washing hands, staying home if you are sick, etc.).

And should you find yourself falling ill - particularly if you are in a high risk group - contact your doctor early for antivirals, which can help reduce the duration and severity of symptoms.