Clinical features of the initial cases of 2009 pandemic influenza A (H1N1) virus infection in an university hospital of Morocco

Int Arch Med. 2010 Oct 27;3:26. doi: 10.1186/1755-7682-3-26.


Background: The first case of 2009 pandemic influenza A (H1N1) virus infection in our center was documented on June 15. Subsequently, persons with suspected cases of infection and contacts of those with suspected infection were tested. Persons in whom infection was confirmed were hospitalized and quarantined, and some of them were closely observed for the purpose of investigating the nature and duration of the disease. The aim of the present study was to describe baseline characteristics, treatment, outcomes, hospital length of stay and mortality of the first 186 cases of influenza A (H1N1) virus infection, with special interest in those developing severe respiratory failure with intensive care unit (ICU) care requirement.

Methods: observational study of 186 consecutive cases of influenza A (H1N1) virus infection admitted in 3 departments that were reference centers for the care of patients with influenza A and 4 ICU in Ibn Sina university hospital (Rabat, Morocco) between June and December 2009. Real time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) testing was used to confirm infection. Demographic data, symptoms, comorbid conditions, illness progression, laboratory and chest radiologic findings, treatments, clinical outcomes and ICU care requirement were closely monitored.

Results: The mean age of the 186 patients was 17.6 ± 14.8 years, 47.8% had less than 14 years and 57% were male. The median duration of symptoms before hospital admission was 3 days (interquartile range (IQR): 2-5). The most common symptoms were fever (in 91.5% of the patients), cough in 92.5%, and nasal congestion in 62.4%. Twenty four percent of patients had comorbid respiratory disorders and 7.5% were pregnant. Abnormalities in chest radiography were detected in 26.3% of 186 patients on admission or after hospitalization. Twenty patients have required ICU care and 10 have required mechanical ventilation. The hospital length of stay was 5 days (IQR: 4-5). The following were risk factors of ICU admission: older age (p = 0.03), long duration of symptoms (p = 0.07), asthma (p = 0.01), obesity (P < 0.001), abnormalities of chest radiography (P < 0.001), leukocytosis (p = 0.005), and higher C-reactive protein (CRP) (P < 0.001). The ICU length of stay was 4 days (IQR: 3-6.7). The mortality rate was 3.5% among all patients and 30% among ICU patients.

Conclusions: Close observation of patients infected with the 2009 pandemic influenza A (H1N1) virus infection provided us with several information. The influenza A (H1N1) virus infection affected young people particularly, with comorbid respiratory disorders. Risk factors of ICU admission were older age, long duration of symptoms, asthma, obesity, abnormalities of chest radiography, leukocytosis and higher CRP. Clinicians should be aware of complications of influenza A (H1N1) virus infection, particulary in patients with risk factors.