Authors:
Howard PF, McCaw JM, Richmond PC, Nissen M, Sloots T, Lambert SB, et al.
Authors notes:
Influenza and other Respiratory Viruses. 2012;7(3):330-339
Keywords:
Epidemiology, Human, Influenza, Influenza vaccines, Picornavirus infection, Respiratory tract infection
Abstract
Viral respiratory infections are associated with significant morbidity and mortality.
We looked for respiratory viruses in a population-based sample of healthy adults with influenza-like illness (ILI).
We investigated host and spatio-temporal associations with virus isolation and host, spatio-temporal and virus associations with self-reported symptoms.
Of 643 samples analysed, a virus was identified in 44%.
Half were picornaviruses, with influenza and coronaviruses the next most common. Individuals with influenza were significantly less likely to have been immunised than the reference (virus negative) population (OR=0·52 (0·31, 0·87) P=0·01).
The mean symptom score (95% CI) reported by individuals with influenza was significantly higher than in all other episodes [Influenza: 10·2 (9·4, 10·9); Other: 7·4 (7·2, 7·7); Difference (95% CI): 2·5 (1·5, 3·5); P<0·001].
In an analysis restricted to influenza-positive cases, the symptom score was not attenuated by vaccination.
Our findings indicate that a greater number of symptoms are displayed by individuals presenting with influenza confirmed ILI compared with other agents that cause ILI.
While influenza vaccination reduced the probability of influenza virus detection, symptom score for influenza-positive ILI was not attenuated