Risk factors associated with severe manifestations of 2009 pandemic influenza A (H1N1) infection in China: a case–control study

Abstract

BackgroundNo studies on the risk factors of 2009 pandemic influenza A (H1N1) in China have been reported. We aimed to investigate the risk factors for severe manifestations of 2009 pandemic H1N1 influenza in ChinaMethodsA case–control study with 343 severe hospitalized patients and 343 randomly selected mild controls was conducted. The diagnosis was established by assessment of clinical symptoms and confirmed by the real-time reverse-transcriptase-polymerase chain reaction assay. Severe or mild patients were classified by uniform criteria issued by the Ministry of Health in China.ResultsThe multivariable logistic regression analysis showed that the overweight or obese subjects admitted to hospital with H1N1 influenza were more likely to experience severe manifestations. The ORs were 3.70 (95% CI: 2.04-6.72) and 35.61 (95% CI: 7.96-159.21) respectively. Subjects at age less than 5 years or older than 60 years had an increased risk of severe manifestations (OR = 21.14, 95% CI: 7.79-57.33). We also observed increased risk among subjects with longer time interval from symptom onset to hospital admission (OR = 3.26, 95% CI: 2.08-5.11) or peasants (OR = 9.79, 95% CI: 5.11-18.78). Those with chronic disorders had increased risk of severe manifestations of H1N1 influenza.ConclusionWe provide evidence on the risk factors associated with severe manifestations of 2009 pandemic H1N1 influenza in a study of hospitalized subjects in China.

Predictors for fatal human infections with avian H7N9 influenza, evidence from four epidemic waves in Jiangsu Province, Eastern China, 2013‐2016

“…According to the surveillance data of Jiangsu Provincial CDC, the overall obesity rate has increased from 9.5% to 14.6% from 2007 to 2013. It was reported that overweight could impair immunity against the influenza virus and was associated with an increased risk of severe infection . The increasing trend of overweight observed in the study has reminded public health experts of the importance of strengthening health education and of promoting precaution implementation in this high‐risk population.…”

Obesity Increases Mortality and Modulates the Lung Metabolome during Pandemic H1N1 Influenza Virus Infection in Mice

“…Epidemiological evidence demonstrates that obesity increases the likelihood of severe influenza infection complications in humans (17, 37–40), and several mouse models have also confirmed this outcome (10–15, 36). Obesity exacerbates lung inflammation and pathology, alters lung immune cell populations, impairs lung healing and in some cases increases viral titers during influenza infection in mice (10–15, 36).…”

“…Following the emergence of the 2009 pH1N1 strain, obesity was reported to be an independent risk factor for greater pH1N1 (17, 37–40) and seasonal (46–48) influenza infection severity. In this study, we provide an in-depth analysis of the immunologic and metabolic complications associated with obesity during infection with the 2009 pH1N1 influenza.…”

Dose‐response relationship between weight status and clinical outcomes in pediatric influenza‐related respiratory infections

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