RT Journal Article SR Electronic T1 When is acute persistent cough in school-age children and adults whooping cough? JF British Journal of General Practice JO Br J Gen Pract FD British Journal of General Practice SP e573 OP e579 DO 10.3399/bjgp13X670705 VO 63 IS 613 A1 Kathryn Philipson A1 Felicity Goodyear-Smith A1 Cameron C Grant A1 Angela Chong A1 Nikki Turner A1 Joanna Stewart YR 2013 UL http://bjgp.org/content/63/613/e573.abstract AB Background Pertussis is a vaccine modified disease in most age groups and hence subtle in its presentation. Current diagnostic approaches require relatively invasive sampling.Aim To determine the incidence of B. pertussis infection among people aged 5–49 years identified in primary care with acute persistent cough using an oral fluid based diagnostic test.Design and setting Active surveillance of acute persistent cough of 2 weeks duration or greater was established in Auckland, New Zealand from May to October 2011. The 15 participating primary care practices provided care for a socioeconomically diverse population.Method Recent B. pertussis infection was determined by measurement of IgG antibodies to pertussis toxin (PT) in an oral fluid sample. An IgG antibody titre to PT of ≥70 arbitrary units defined recent infection. Participants reported symptoms at presentation and kept a cough diary.Results A total of 226 participants were enrolled: 70 (31%) were children (5–16 years) and 156 (69%) were adults (17–49 years). Oral fluid samples were obtained from 225 participants. Ten per cent (23/225) had recent B. pertussis infection including a larger proportion of children than adults (17% versus 7%, P = 0.003). Neither cough duration nor any individual symptom discriminated between those with and without recent B. pertussis infection.Conclusion Pertussis is a frequent cause of acute persistent cough presenting to primary care. Clinical differentiation of pertussis from other causes of acute persistent cough is difficult. An oral fluid based diagnostic test, which is less invasive than other diagnostic approaches, has high acceptability in primary care.