Common Respiratory Virus Infections: Update and New Treatments

Common Viruses, Pronounced Impact

On a year-to-year basis, viral infections such as Middle East respiratory syndrome, severe acute respiratory syndrome, pandemic H1N1 "swine flu," and H7N9 "avian influenza" garner considerable attention from the general public and infection control specialists.

However, most people are at much greater risk of developing illnesses, which can be severe, from less exotic respiratory viruses, such as influenza, parainfluenza virus (PIV), and respiratory syncytial virus (RSV). When time lost from work or school, direct healthcare costs, and unnecessary use of antibiotics are considered, the societal and healthcare burdens of these more mundane viral infections become even more pronounced.

Although management of lower respiratory tract viral infections, especially in immunocompromised patients, can prove challenging, such advances as rapid multiplex polymerase chain reaction (PCR) panels that test for multiple viral and bacterial pathogens and the development of new antiviral approaches are changing the field.

Antimicrobial Stewardship

Antibacterial treatment of respiratory viral infections is common and contributes to increased cost (Table 1).^{[1,2,3,4,5,6]}

Table 1. Snapshot of Consequences of Inappropriate Antibiotic Use in Treating Respiratory Viral Infections

Increased costs^[2] Antibiotic expenditures in 2009 totaled $10.7 billion. When the estimated proportion of inappropriate or unnecessary antibiotics is accounted for, over $3 billion is spent yearly in excess costs^[1] The majority (61.5%) of expenditures occurred in the outpatient setting Quinolones accounted for the greatest expenditure by class Increased adverse events Clostridium difficile infection is generally associated with antibiotic use and caused approximately 1.5 million infections and 29,000 deaths in 2011^[3] There are an estimated 142,000 annual visits to the emergency department for adverse events related to antibiotics^[4] Increased community and personal antimicrobial resistance Longer durations of antibiotic use and multiple courses are associated with higher rates of resistance^[5] Patients prescribed antibiotics in the primary care setting for respiratory or urinary infection develop bacterial resistance, lasting from 1 to 12 months^[2] Regions with high antibiotic prescribing rates also have higher rates of nonsusceptibility among invasive pneumococcal disease isolates^[6]

Increased costs^[2]
- Antibiotic expenditures in 2009 totaled $10.7 billion. When the estimated proportion of inappropriate or unnecessary antibiotics is accounted for, over $3 billion is spent yearly in excess costs^[1]
  - The majority (61.5%) of expenditures occurred in the outpatient setting
  - Quinolones accounted for the greatest expenditure by class
Increased adverse events
- Clostridium difficile infection is generally associated with antibiotic use and caused approximately 1.5 million infections and 29,000 deaths in 2011^[3]
- There are an estimated 142,000 annual visits to the emergency department for adverse events related to antibiotics^[4]
Increased community and personal antimicrobial resistance
- Longer durations of antibiotic use and multiple courses are associated with higher rates of resistance^[5]
- Patients prescribed antibiotics in the primary care setting for respiratory or urinary infection develop bacterial resistance, lasting from 1 to 12 months^[2]
- Regions with high antibiotic prescribing rates also have higher rates of nonsusceptibility among invasive pneumococcal disease isolates^[6]

An estimated 25%-50% of antibiotic use may be inappropriate.^[7,8] Antibiotics are prescribed in over 100 million ambulatory visits annually, with respiratory conditions being the most common (41%) prescribing indication.^[8] Older age and emergency department settings are associated with greater use of broad-spectrum antibiotics.^[8]

Diagnostic uncertainty is a major driver of antimicrobial overuse. The widespread use of rapid respiratory virus detection has improved diagnostic accuracy, but has not yet been unequivocally linked to more focused use of antimicrobials. However, with increased urgency to control antibiotic use, this situation may improve.

Earlier this year, the American College of Physicians (ACP) and the Centers for Disease Control and Prevention (CDC) released best practices for appropriate use of antibiotics in respiratory tract infection in adults. These practices comprise four high-value care points (Table 2).^[1]

Table 2. ACP and CDC's Advice on Appropriate Antibiotic Use for Acute Respiratory Tract Infection in Adults^[1]

Clinicians should not perform testing or initiate antibiotic therapy in patients with bronchitis unless pneumonia is suspected. Clinicians should test patients with symptoms suggestive of group A streptococcal pharyngitis (for example, persistent fevers, anterior cervical adenitis, and tonsillopharyngeal exudates or other appropriate combination of symptoms) by rapid antigen detection test and/or culture for group A Streptococcus. Clinicians should treat patients with antibiotics only if they have confirmed streptococcal pharyngitis. Clinicians should reserve antibiotic treatment for acute rhinosinusitis for patients with persistent symptoms for more than 10 days, onset of severe symptoms or signs of high fever (> 39°C) and purulent nasal discharge or facial pain lasting for at least 3 consecutive days, or onset of worsening symptoms following a typical viral illness that lasted 5 days that was initially improving (double sickening). Clinicians should not prescribe antibiotics for patients with the common cold.

Clinicians should not perform testing or initiate antibiotic therapy in patients with bronchitis unless pneumonia is suspected.
Clinicians should test patients with symptoms suggestive of group A streptococcal pharyngitis (for example, persistent fevers, anterior cervical adenitis, and tonsillopharyngeal exudates or other appropriate combination of symptoms) by rapid antigen detection test and/or culture for group A Streptococcus. Clinicians should treat patients with antibiotics only if they have confirmed streptococcal pharyngitis.
Clinicians should reserve antibiotic treatment for acute rhinosinusitis for patients with persistent symptoms for more than 10 days, onset of severe symptoms or signs of high fever (> 39°C) and purulent nasal discharge or facial pain lasting for at least 3 consecutive days, or onset of worsening symptoms following a typical viral illness that lasted 5 days that was initially improving (double sickening).
Clinicians should not prescribe antibiotics for patients with the common cold.

One cannot be dogmatic about equating the presence of a respiratory viral infection with the absolute absence of another process. Respiratory viral infections can also be associated with bacterial coinfections and superinfections. In addition, in highly immunocompromised patients, resolution of viral infections can sometimes be followed by development of invasive filamentous fungal infection (eg, aspergillosis).

Comments

Commenting is limited to medical professionals. To comment please Log-in.

Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.