Severe influenza A (H1N1)v in patients without any known risk factor

A proportion of pandemic flu cases requires critical care. Several risk factors are associated with progressive illness. The World Health Organization recommends prompt antiviral treatment when risk factors are present [1]. Nevertheless, in Rello and colleagues' work, 15 out of 32 critical pandemic flu patients did not have any risk factor [2]. In our hospital, 25 pandemic flu cases have been diagnosed by RT-PCR thus far. Three of these cases required critical care. Noteworthy, those patients had been visited in emergency services 2 to 3 days before. The clinical picture did not prompt the physician to prescribe any antiviral, and oseltamivir treatment was delayed 5 days or more. In contrast, in the group of patients who did not require critical care (22 patients), only three patients had a prior emergency visit (Fisher's exact test P = 0.009) and 18 patients received antiviral treatment in the first 48 hours of symptoms (Fisher's exact test P = 0.009). In Rello and colleagues' study, the median number of days from illness onset to initiation of antiviral treatment was 4 days. Patients with risk factors were probably treated immediately, however, and patients without any risk factors were probably treated later. Some evidence suggests that early antiviral treatment is associated with a good prognosis [3]. Rello and colleagues may provide the mean of treatment delay days in patients without any risk factor and any putative differences with the rest of patients. Early antiviral treatment with active antiviral drugs may prevent severe cases in patients without any risk factor. The authors may also inform about any other difference in this group of patients.