Appendix 1.

Search terms

ID	Search
#1	((exp Respiratory Tract Diseases/) OR (exp Respiratory Tract Infections/) OR ((respiratory adj3 (infection* or disease* or symptom*)).tw.) OR (exp Sick Building Syndrome/) OR (exp Otitis Media/) OR (exp Common Cold/) OR (exp Influenza, Human/) OR (exp Asthma/) OR (exp Rhinitis/) OR (exp Sinusitis/) OR (exp Cough/) OR (exp pharyngitis/) OR (exp laryngitis/) OR ((laryngotracheobronchit*). ti,ab.) OR (exp tonsillitis/) OR (exp peritonsillar abscess/) OR (exp croup/) OR (exp epiglottitis/) OR ((supraglottit*).ti,ab.) OR ((rhinosinusit*).ti,ab.) OR (exp otitis media/))
#2	((C reactive protein).ti,ab.)
#3	((exp anti-infective agents/) OR (exp anti-bacterial agents/) OR ((anti-biotic* or antibiotic* or anti-infect* antiinfect* or antibacteria* or anti-bacteria*).ab,ti.) OR ((microbicide* or anti-microbi* or antimicrobi* or microbi*).ab,ti.) OR ((beta-lactam* or betalactam* or B-lactam* or aminoglycoside* or vancomycin).ab,ti.))
#4	(#1 AND #2 AND #3)

No restriction was placed on the publication language. References were also screened from retrieved articles and reviews to identify additional articles that met the eligibility criteria.