Viral pneumonia is a common complication of influenza-like illnesses and is a complication of SARS-COV-2. Viral pneumonia may clear up on its own; however, when severe, it can be life-threatening. Viruses are generally not as common a cause of CAP as some bacteria. However, as well as being a primary pathogen, viruses can be a co-pathogen with bacteria, particularly in those with severe illness requiring admission to ICU and in ventilator-associated pneumonia.
Viral pneumonia is predominant among very young children (< 5 years) and adults aging > 50 years. The most common isolates in adults are adenoviruses, coronaviruses, human metapneumovirus, human rhinoviruses, influenza viruses, parainfluenza viruses and respiratory syncytial virus, but an exact picture of epidemiologic findings is difficult to establish due to not optimal surveillance systems in all countries, a high rate of coinfections, and the lack of a precise definition of viral pneumonia.
Viral infections are the leading cause of community-acquired pneumonia (CAP) and are an important source of morbidity and mortality. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly discovered virus causing coronavirus disease 2019 (COVID-19)...
More than 20 viruses have been linked to CAP. Clinical presentation, laboratory findings, biomarkers, and radiographic patterns are not characteristic to specific viral etiology. Currently, laboratory confirmation is most commonly done by detection of viral nucleic acid by reverse transcription-PCR of respiratory secretions. Among viral pathogens, influenza remains the clinically most significant viral cause of CAP in adults; other common viral pathogens include RSV, parainfluenza viruses (PIV), and adenovirus.
We need better tests to identify the small proportion of children with pneumonia who have bacterial infection so that antibiotics can be appropriately prescribed for these children and avoided in children with viral infection for whom antibiotic therapy is unnecessary.
Primary influenza pneumonia has a high mortality rate during pandemics, not only in immunocompromised individuals and patients with underlying comorbid conditions, but also in young healthy adults.
Low-dose therapies appear to be effective. Evidence from a randomized control study found dexamethasone is effective in decreasing mortality in severe COVID-19 cases.
Since the last century, a number of devastating
pandemics and outbreaks related to respiratory viruses have occurred. Recently, there has been a
growing interest in the development of new antiviral medications for respiratory infection. In this
article, we provide an overview of pneumonia
caused by influenza and other respiratory viruses
from the practicing clinician perspective and with
a focus on the adult population.
More than 60% of pediatric pneumonia cases diagnosed worldwide are caused by viruses, according to a new study in The Lancet based on surveillance in seven countries.
Viral infection is present in a high proportion of patients with CAP. The true proportion of viral infection is probably underestimated because of negative test results from nasopharyngeal or oropharyngeal swab PCR. There is increased mortality in patients with dual bacterial and viral infection.
About 200 million cases of viral community-acquired pneumonia occur every year—100 million in children and 100 million in adults. Molecular diagnostic tests have greatly increased our understanding of the role of viruses in pneumonia, and findings indicate that the incidence of viral pneumonia has been underestimated. In children, respiratory syncytial virus, rhinovirus, human metapneumovirus, human bocavirus, and parainfluenza viruses are the agents identified most frequently in both developed and developing countries.
Viral pneumonia, which is typically associated with disease in childhood, is increasingly recognized as causing problems in adults. Certain viruses, such as influenza virus, can attack fully immunocompetent adults, but many viruses take advantage of more-vulnerable patients.
Distinguishing viral pneumonia from bacterial pneumonia is difficult. There are important cues in history and the examination that can help differentiate the two.
The traditional role of viral pneumonia was as a disease found predominantly in the very young, the elderly, and those exposed to influenza. In the past, the diagnosis of viral pneumonia was predicated on it being somewhat a diagnosis of exclusion.