What are the causes and symptoms of viral respiratory infection (VRI)?

From the Guidelines

Viral respiratory infections (VRI) are primarily caused by respiratory syncytial virus (RSV), influenza, parainfluenza virus, adenovirus, rhinovirus, and metapneumovirus, and their symptoms include cough, shortness of breath, and fever, which can be managed with rest, hydration, and over-the-counter medications, but may require antiviral treatment in severe cases, especially in immunocompromised patients 1. The causes of VRI can be identified using rapid PCR panels, which can detect various respiratory viruses, including RSV, influenza, and parainfluenza virus 1. Some key points to consider in the management of VRI include:

• Rest and adequate hydration to help manage symptoms
• Over-the-counter medications like acetaminophen or ibuprofen to manage fever and pain
• Nasal congestion can be relieved with saline nasal sprays or decongestants
• Cough suppressants containing dextromethorphan may help with persistent cough
• Antiviral medications like oseltamivir may be beneficial in certain cases, such as influenza, if started within 48 hours of symptom onset 1
• Prevention strategies include frequent handwashing, avoiding close contact with sick individuals, and annual influenza vaccination
• If symptoms worsen significantly, persist beyond 10-14 days, or include difficulty breathing, high fever, or severe chest pain, medical attention should be sought as these may indicate complications or bacterial superinfection requiring different treatment approaches. It is essential to note that certain viruses, like RSV, can cause severe infection in immunocompromised patients, with mortality rates up to 80% in HCT recipients, and require hospitalization for treatment 1. In addition, the diagnosis and management of bronchiolitis, a common lower respiratory infection in infants, should be based on evidence-based guidelines, which recommend supportive care, including oxygen therapy, hydration, and monitoring, as the mainstay of treatment, with no clear benefit from bronchodilators, corticosteroids, or antibacterial medications 1.

From the FDA Drug Label

Of the 452 influenza-infected subjects, 67% were infected with influenza A and 33% with influenza B Efficacy in this trial was determined by the time to alleviation or resolution of influenza signs and symptoms, measured by a composite endpoint that required the following four individual conditions be met: i) alleviation of cough, ii) alleviation of coryza, iii) resolution of fever, iv) parental opinion of a return to normal health and activity The efficacy endpoint for all of these trials was the incidence of laboratory-confirmed clinical influenza defined as meeting all the following criteria (all signs and symptoms must have been recorded within 24 hours): oral temperature greater than or equal to 99.0ºF (37. 2ºC), at least one respiratory symptom (cough, sore throat, nasal congestion), at least one constitutional symptom (aches and pain, fatigue, headache, chills/sweats), and either a positive virus isolation or a four-fold increase in virus antibody titers from baseline Laboratory-confirmed clinical influenza was defined as meeting all of the following criteria: oral temperature at least 100°F (37. 8°C), cough and/or coryza recorded within 48 hours, and either a positive virus isolation or a four-fold or greater increase in virus antibody titers from baseline or at illness visits

The causes of viral respiratory infection (VRI) are not explicitly stated in the provided text, but it can be inferred that the causes are related to influenza A and B viruses. The symptoms of VRI include:

• Respiratory symptoms: cough, sore throat, nasal congestion, coryza
• Constitutional symptoms: fever, aches and pain, fatigue, headache, chills/sweats 2

From the Research

Causes of Viral Respiratory Infection (VRI)

• Viruses are the primary cause of acute respiratory tract infections (ARIs), with influenza, respiratory syncytial virus, parainfluenza, and adenovirus being the most commonly encountered viruses 3
• The majority of ARIs are transmitted through large droplets, but transmission through contact and infectious respiratory aerosols may also occur 3

Symptoms of Viral Respiratory Infection (VRI)

• Lower respiratory tract infections, such as pneumonia, can be a complication of influenza, especially in children under 2 years old and those with severe chronic underlying disease 4
• Acute respiratory distress syndrome (ARDS) can occur in patients with H1N1 influenza A virus-associated acute lung injury 5
• Symptoms of VRI can include fever, cough, and shortness of breath, and can range from mild to severe 6, 7

Treatment and Management of VRI

• Oseltamivir is an antiviral medication that can be used to treat influenza, and has been shown to reduce the risk of clinical failure in hospitalized patients with influenza-associated lower respiratory tract infection 7
• Corticosteroids may be used in combination with oseltamivir to treat patients with severe respiratory distress, but should be administered with caution and only after initiating antiviral therapy 6, 5
• Infection prevention and control measures, such as hand hygiene and respiratory precautions, are important for preventing the transmission of VRI in healthcare settings 3