Publications

Background:
Persistent cough following an acute respiratory tract infection (RTI) is common in children. From 2001-5 we prospectively recruited 179 children aged 5-16 years with a cough lasting at least 14 days. Of these, 37% had serologically confirmed pertussis. In this study, we retrospectively analysed the blood samples, nasopharyngeal aspirates (NPAs), and clinical cough data from these children. Our aims were to estimate the prevalence of Mycoplasma pneumoniae (Mp) and respiratory viruses and compare cough duration between children with different infections.
Method:
We detected Mp by Polymerase Chain Reaction (PCR) of NPAs and IgM serology. We detected rhinoviruses, influenza viruses, respiratory syncytial viruses and human metapneumovirus by PCR of NPAs. We used Kaplan-Meier analyses to calculate median cough duration with 95% confidence intervals (CIs) and compared cough durations using the log rank statistic.
Results:
We detected Mp in 22/170 children with sufficient NPA and/or blood samples (12.9%). We detected viruses in 32/155 children with sufficient NPAs (20.6%).
Based on PCR, children with Mp had a shorter duration of cough (median 39 days, 95% CI 22.4-55.6) than pertussis-negative children with single virus or no detectable infections (median 70 days, 95% CI 61.2-78.8, p<0.001). Cough duration in children with positive Mp serology (median 39 days, 95% CI 24.4-53.6) was significantly shorter than in children with pertussis (median 118 days, 95% CI 82.3-153.7, p<0.001).
Conclusion:
Although Mp and viruses usually cause acute RTIs, they are also found in children with persistent cough. Identifying these infections will help clinicians provide more accurate prognostic information on likely cough duration.