title: Incidence of respiratory viral infections detected by PCR and real-time PCR in adult patients with community-acquired pneumonia: a meta-analysis.
abstract: BACKGROUND
  With the development of more rapid and sensitive detection methods based on PCR techniques, the contributions of respiratory viral infections to community-acquired pneumonia (CAP) in adult patients are being more and more recognized. Yet, up to now, there has been a lack of synthetic data that clearly demonstrates the incidence of respiratory viral infections in adult patients with CAP.
  
  
  OBJECTIVE
  We intended to demonstrate the incidence of respiratory viral infections detected by PCR and real-time PCR in adult patients with CAP.
  
  
  METHODS
  We searched PubMed and Embase for studies providing the incidence of respiratory viral infections in adult patients with CAP. We investigated potential sources of heterogeneity by a univariant metaregression analysis and calculated the combined incidence of viral infections, viral infections mixed with other pathogens and individual respiratory virus species.
  
  
  RESULTS
  We eventually identified 23 eligible reports with a total number of 6,404 patients. Incidences ranged from 8.6 to 56.2% for overall respiratory viral infections. We noted significant heterogeneity in incidence estimates for the incidence of viral infections (Cochran's χ(2) = 269.9, p < 0.0001, I(2) = 91.8%). The combined incidence of viral infections was 22.4% (95% CI = 19.0-25.7). Incidences of viral coinfections with other pathogens ranged from 3 to 28%. A high level of heterogeneity was identified as well during the estimates for incidences of coinfections (χ(2) = 200.9, p < 0.0001, I(2) = 91.5%). The combined incidence of viral coinfections with other pathogens was 12.4% (95% CI = 9.7-15.0). Our heterogeneity analyses suggested that a lower respiratory tract sample was associated with higher overall viral incidence. Moreover, the influenza virus, rhinovirus and coronavirus were the 3 most frequently detected viral pathogens in adult patients with CAP according to our study.
  
  
  CONCLUSIONS
  Respiratory viruses are probably crucial pathogens of adult patients with CAP, with the influenza virus being the most frequent viral pathogen identified. More than half of the viral infections are characterized as mixed infections with other pathogens.
authors: Department of Respiratory and Critical Care Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors: Xiaodong
authors: X
authors: Wu
authors: Qin
authors: Q
authors: Wang
authors: Min
authors: M
authors: Wang
authors: Xin
authors: X
authors: Su
authors: Zheng
authors: Z
authors: Xing
authors: Weiyun
authors: W
authors: Zhang
authors: Yi
authors: Y
authors: Shi
mesh_terms: D017714:Community-Acquired Infections / Q000453:epidemiology / Q000821:virology; D006801:Humans; D011024:Pneumonia, Viral / Q000453:epidemiology* / Q000821:virology*