June 30 2009 : Novel H1N1 Influenza Clinical Update #4

Memo: Novel H1N1 Influenza

To: Health Care Providers, Hospital ERs, ICPs, CHCs, Wabano
From: Isra Levy, Medical Officer of Health
Vera Etches and Nadine Sicard, Associate Medical Officers of Health
Date: June 30, 2009

Thank you for your ongoing collaboration in Ottawa’s response to the challenges presented by the novel H1N1 influenza virus pandemic. Further to previous memoranda on this subject, and as a supplement to the information sent to you this week as part of OPH’s Physicians’ Update, please see information of clinical relevance and interest below.

Epidemiology of novel H1N1 influenza in Ottawa

The following epidemiological profile provides information on our local situation. From the end of April until June 30, 2009:

• There have been 335 laboratory-confirmed cases of the virus, with a median age group of 15 to 19 years (ranging from <1 year to 80-84 years). In contrast, the median age for cases with seasonal influenza is 33 years.
• Of the reported cases, 38 were admitted to hospital. The median age of hospitalized cases is 17 years and the maximum age is 75 years.
• Symptom data are available for over 50 cases, and most people report fever and cough as the predominant symptoms. The only apparent difference between hospitalized and non-hospitalized cases is the severity of symptoms. One death in a person with H1N1 influenza has occurred.

Summer surveillance

The number of new cases reported by OPH weekly, and the rate of increase in the number of cases, is expected to decrease as testing is now recommended only for severely ill (usually hospitalized) patients or patients with a high probability of developing complications. OPH is now following up with individual cases only if they may be at risk of more severe outcomes, e.g., pregnant women. OPH continues investigations of outbreaks. Summer surveillance activities will include monitoring high rates of absenteeism with influenza-like illnesses (ILI) in camp and summer school programs.

Ongoing collaboration between OPH and local hospitals is yielding surveillance information about the impact of novel H1N1 influenza on acute care services. CHEO, in particular, has reported days where there has been an increase of up to 25 per cent in the number of visits to the emergency department; the majority of these visits were due to non-severe ILI.

Reducing the burden on emergency departments

OPH’s public messaging encourages patients with mild illness that cannot be handled in the home to be assessed by healthcare providers in an outpatient setting. Your assessment of patients in your offices is greatly appreciated. In general patients should be referred to emergency departments only when they present severe symptoms such as respiratory difficulty. Treatment with antivirals, according to current recommendations, is only indicated in patients with fever and acute ILI, pneumonia requiring hospitalization, or in patients with ILI and who are at risk for complicated disease.