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Updated: Aug 7, 2026
Rapid Molecular Detection and Differentiation of Influenza Viruses A and B
Published on: January 30, 2017
Prospective comparative study of characteristics associated with influenza A and B in adults
A Chagvardieff1, N Persico1, C Marmillot1
1Service d'accueil des urgences adultes, CHU Nord, chemin des Bourrely, 13915 Marseille cedex 20, France.
Objectives:
To describe and compare the epidemiological characteristics associated with influenza type A and B as well as the characteristics associated with influenza pneumonia. The secondary objective was to evaluate the performance of influenza rapid diagnostic tests (RDT) in the emergency department.
Patients And Methods:
Prospective study, including 251 adult patients admitted to the emergency department during the 2013-2014 influenza outbreaks for flu-like illness confirmed by RT-PCR.
Results:
A total of 106 patients were infected with influenza type B (42%) and 145 with influenza type A (58%). Mean age was 56 and the sex-ratio was 0.9. In a multivariate analysis, the only factor independently related with the type of influenza strain was the patient's age. Overall, 17% of influenza-infected patients were vaccinated and 38% presented with pneumonia, with no significant difference between strains. In a univariate analysis, the risk factors associated with the occurrence of pneumonia were age, vaccination, and chronic obstructive pulmonary disease. Only 22% of samples positive by RT-PCR for influenza B and 40% for influenza A were positive by RDT.
Conclusion:
Influenza type A and type B had similar clinical and biological signs, including severity. Influenza type B should not be neglected. Any emergency department may use the RDT for its ease-of-use and rapidity. However, its low sensitivity should be taken into consideration when interpreting results.
