Other adjunctive methods have not been found to have significant impact [16].
Prevention of Pneumonia
Prevention of pneumococcal pneumonia is twofold: prevention of infection caused by S. pneumoniae and prevention of influenza infection. As influenza infection is a risk factor for bacterial infection, specifically with S. pneumoniae, influenza vaccination can prevent bacterial pneumonia [60]. In their most recent recommendations, the CDC continues to recommend routine influenza vaccination for all persons aged greater than 6 months, unless otherwise contraindicated [61].
There are 2 vaccines for prevention of pneumococcal disease: the pneumococcal polysaccharide vaccine (PPSV23) and a conjugate vaccine (PCV13). Following vaccination with PPSV23, 80% of adults develop antibodies against at least 18 of the 23 serotypes [62]. Despite this response, PPSV23 is reported to be protective against invasive pneumococcal infection; yet there is no consensus regarding PPSV23 leading to decreased rates of pneumonia [63]. On the other hand, PCV13 vaccination was associated with prevention of both invasive disease and community-acquired pneumonia in adults 65 years or older [64]. The CDC recommends that all children aged 2 or under receive PCV13, whereas those aged 65 or older should receive PCV13 followed by a dose of PPSV23 [65]. The dose of PPSV23 should be given ≥1 year following the dose of PCV13 [66].Persons < 65 years of age with immunocompromising and certain other conditions should also receive vaccination [67] (Table 7). Full details, many scenarios, and timing of vaccinations can be found at www.cdc.gov/vaccines/schedules/downloads/adult/adult-schedule.pdf.
Cigarette smoking increases the risk of respiratory infections as evidenced by smokers accounting for almost half of all patients with invasive pneumococcal disease [11]. As this is a modifiable risk factor it should be a goal of a comprehensive approach towards prevention of pneumonia.
Summary
CAP remains a leading cause of hospitalization and death in the 21st century. Traditionally, pneumococcus has been considered the major pathogen causing CAP; however, the 2015 EPIC study found that in only 5% of patients diagnosed with CAP was S. pneumoniae detected. Despite the new findings, it is still recommended that empiric treatment for CAP target common typical bacteria (pneumococcus, H. influenzae, Moraxella catarrhalis) and atypical bacteria (M. pneumonia, C. pneumoniae, L. pneumophila).
Because diagnosing pneumonia through history and clinical examination is less than 50% sensitive, a chest imaging study (a plain chest radiograph or a chest CT scan) is usually required to make the diagnosis. Laboratory tests, such as sputum Gram stain/culture, blood culture, urinary antigen tests, PCR test, procalcitonin, and CRP are important adjunctive diagnostic modalities to assist in the diagnosis and management of CAP. However, no single test is sensitive and specific enough to be a stand-alone test. They should be used in conjunction with history, physical examination, and imaging studies. Because vaccination (PPSV23, PCV13, and influenza vaccine) remains the most effective tool in preventing the development of CAP, clinicians, should strive for 100% vaccination rates in appropriate persons.
Corresponding author: Tze Shein Lo, MD, University of North Dakota, 1919 Elm Street, Fargo, ND 58102, tzeshein.lo@med.und.edu.
Financial disclosures: None.
Author contributions: drafting of article, PM, TSL; critical revision of the article, PM, TSL.