Background: In 2011-2012 a large pertussis outbreak occurred in England. This provided an opportunity to estimate the disease burden in those aged 5 years and over. As pertussis is likely to be under reported both laboratory-confirmed and non-confirmed cases were included.
Methods: Laboratory-confirmed cases of pertussis, as well as their coughing but non-confirmed household members, were sent a questionnaire that collected information on clinical features and quality of life for the most severe day of disease and the day the patient filled in the questionnaire. The EuroQol-5 dimension questionnaire (EQ-5D) was used to evaluate quality of life. The duration of symptoms was obtained by contacting the patient every two weeks until symptoms stopped.
Results: Data for 535 (out of 1262) laboratory confirmed pertussis patients and 44 (out of 140) coughing household contacts was available for analysis. On the most severe day, 56% of laboratory-confirmed cases reported they had 20+ more paroxysms, 58% reported they had a severe cough and 46% reported disruption of sleep for more than 4 hours. For non-confirmed coughing household contacts there were a similar number of coughing spells per day at the height, though the cough was reported to be less severe and to cause less sleep disruption. The main clinical symptoms on the worst day for both were shortness of breath, tiredness, sore ribs and vomiting. The duration of symptoms for both patient groups was around 160 days (162 and 168 days). Under base case assumptions the overall loss of quality of life was 0.097 QALY (0.089-0.106) for confirmed pertussis cases and 0.0365 QALY (0.023-0.054) for coughing household contacts.
Conclusion: Pertussis is a serious disease in those aged 5 years and over, causing disruption of sleep and daily activities over long period of time. The burden of illness due to undiagnosed pertussis is also considerable.