Table 2.

Detection of respiratory viruses in lower airway secretions during acute exacerbations of COPD

Respiratory virus	Characteristics	Reported prevalence in acute exacerbations
Human rhinovirus	Single-stranded positive sense RNA virus that does not cause extensive cytotoxicity. There are three major species, A, B, and C, that altogether encompass approx. 150 serotypes	13.7–19.7 % [31]; 14.8 % [13.2–16.5 %] [32]
Respiratory syncytial virus	Single-stranded negative sense RNA virus that can cause extensive cytotoxicity	9.4–14.8 % [31]; 9.0 % [7.8–10.4 %] [32]
Influenza	Single-stranded negative sense RNA virus that can cause extensive cytotoxicity. There are three major species, A, B, and C. The influenza virus A comprises several serotypes, including endemic ones	7.1–12.6 % [31]; 8.2 % [7.0–9.5 %] [32]
Parainfluenza virus	Single-stranded negative sense RNA. There are four serotypes	3.1–6.7 % [31]
Human metapneumovirus	Single-stranded negative sense RNA	<2 % [32]
Coronavirus	Single-stranded positive sense RNA virus. There are six serotypes that can infect humans	0.4–2.7 % [31]
Adenovirus	Double-stranded DNA virus. The species B and C that predominantly cause COPD exacerbations altogether comprise 15 serotypes	2.6–5.8 % [31]; <2 % [32]

Numbers represent mean [96 % confidence interval]