Centre de Recherche et de Veille sur les maladies émergentes dans l'Océan Indien, Sainte-Clotilde, La Réunion, France.
PLoS One. 2012;7(9):e44755. doi: 10.1371/journal.pone.0044755. Epub 2012 Sep 12.
The aim of the present study was to weigh up, at the community level, the respective roles played by pandemic Influenza (pH1N1) virus and co-circulating human Non-Influenza Respiratory Viruses (NIRVs) during the first wave of the 2009 pH1N1 pandemic.
A population-based prospective cohort study was conducted in Reunion Island during the austral winter 2009 (weeks 30-44) that allowed identification of 125 households with at least one member who developed symptoms of Influenza-like illness (ILI). Three consecutive nasal swabs were collected from each household member (443 individuals) on day 0, 3 and 8 post-ILI report and tested for pH1N1 and 15 NIRVs by RT-PCR.
Two successive waves of viral infections were identified: a first wave (W33-37) when pH1N1 was dominant and co-circulated with NIRVs, sharply interrupted by a second wave (W38-44), almost exclusively composed of NIRVs, mainly human Rhinoviruses (hRV) and Coronaviruses (hCoV). Data suggest that some interference may occur between NIRVs and pH1N1 when they co-circulate within the same household, where NIRVs were more likely to infect pH1N1 negative individuals than pH1N1 positive peers (relative risk: 3.13, 95% CI: 1.80-5.46, P<0.001). Viral shedding was significantly shorter (P = 0.035) in patients who were co-infected by pH1N1 and NIRV or by two different NIRVs compared to those who were infected with only one virus, whatever this virus was (pH1N1 or NIRVs). Although intense co-circulation of NIRVs (especially hRV) likely brought pH1N1 under the detection threshold, it did not prevent spread of the pandemic Influenza virus within the susceptible population nor induction of an extensive herd immunity to it.
Our results suggest that NIRV co-infections during Influenza epidemics may act as cofactors that contribute to shape an outbreak and modulate the attack rate. They further warrant broad spectrum studies to fully understand viral epidemics.
本研究旨在从社区层面上衡量大流行性流感（pH1N1）病毒和同时流行的人类非流感呼吸道病毒（NIRV）在 2009 年 pH1N1 大流行的第一波期间各自所起的作用。
在 2009 年澳大利亚冬季（第 30-44 周）期间，在留尼汪岛进行了一项基于人群的前瞻性队列研究，该研究鉴定了 125 个至少有一名成员出现流感样疾病（ILI）症状的家庭。从每个家庭的成员（443 人）连续采集 3 次鼻拭子，分别在 ILI 报告后第 0、3 和 8 天进行 pH1N1 和 15 种 NIRV 的 RT-PCR 检测。
鉴定出了两波连续的病毒感染：第一波（W33-37）时 pH1N1 占主导地位且与 NIRV 同时流行，被第二波（W38-44）突然打断，第二波几乎完全由 NIRV 组成，主要为人类鼻病毒（hRV）和冠状病毒（hCoV）。数据表明，当 NIRV 与 pH1N1 在同一家庭中共存时，它们之间可能存在相互干扰，NIRV 更有可能感染 pH1N1 阴性个体，而不是 pH1N1 阳性个体（相对风险：3.13，95%CI：1.80-5.46，P<0.001）。与仅感染一种病毒（pH1N1 或 NIRV）的患者相比，同时感染 pH1N1 和 NIRV 或两种不同 NIRV 的患者的病毒脱落时间明显更短（P=0.035）。尽管 NIRV 的强烈共同流行（尤其是 hRV）可能使 pH1N1 检测不到，但它并未阻止大流行性流感病毒在易感人群中的传播，也未诱导针对该病毒的广泛群体免疫力。
我们的研究结果表明，流感流行期间的 NIRV 合并感染可能作为影响暴发的协同因子，并调节发病率。它们进一步证明需要进行广泛的研究以充分了解病毒流行情况。
