Occurrence of a case of influenza A(H1N1)pdm09 and B co-infection during the epidemic season 2012–2013

Abstract

a b s t r a c tWe report the detection of one case of co-infection with influenza A(H 1 N 1 )pdm09 and B, occurred during the 2012-2013 influenza season in Sicily. The dual infection was identified in a 18-year-old boy, who was not covered by specific vaccination and who had no other pre-existing risk factors. He presented classical symptoms of influenza-like illness developing no respiratory complications. A(H 1 N 1 )pdm09 viral concentration was initially about 10-fold higher than B virus, whereas its clearance was more rapidly achieved than in the case of B virus infection. Although influenza co-infection appears to be a rare event, a continued influenza surveillance activity is recommended, in order to evaluate diversity and evolution, but also to support public health prevention measures.

Diagnosis of Influenza: Only a Problem of Coding?

“…Secondly, more than 25% of all influenza-associated hospitalizations in our study occurred from May to October, thus in periods during which, both in Europe and in Italy, there is no active circulation of influenza viruses [ 23 , 24 ]. Moreover, in our database, the low number of specified and unspecified viral pneumonia codes found in the records during the influenza season could suggest a misclassification of the different viral diseases, supporting the low specificity of influenza codes observed by other authors who reported values ranging from 43% for the ICD-9 CM code 487.8 to 75% for the ICD-9 CM code 487.0 [ 25 ].…”

Clinical implications of dual-positive rapid influenza diagnostic tests during influenza season: Co-colonization, coinfection, or false positive test?

“…Because coinfection with influenza A and B in adults is so unusual, coinfection should not be assumed without additional PCR testing. [3][4][5][6][7][8][9] During the 2013-2014 influenza season, an adult patient in our hospital presented with an influenza-like illness with a dual positive QuickVue Influenza A þ B Test (Quidel Corp, San Diego, Calif) result that warranted further investigation.…”

A six‐plex droplet digital RT‐PCR assay for seasonal influenza virus typing, subtyping, and lineage determination

“…Viruses of the four subtypes/lineages circulate widely in humans and 0.5%‐3.0% of influenza patients are dually infected 2,3 . Such dual infection cases are reported, but not necessarily confined to, children, young adults, pregnant women, and immunocompromised patients 2,4‐6 …”

“…2,3 Such dual infection cases are reported, but not necessarily confined to, children, young adults, pregnant women, and immunocompromised patients. 2,[4][5][6] Quantitative RT-PCR (qRT-PCR) is a sensitive and specific nucleic acid test for detecting influenza virus. 7 Viral loads determined by qRT-PCR assays are suggested to be useful markers for assessing disease severity and for predicting clinical outcomes.…”