PEI Influenza Summary 2016-2017 Season

Summary

  • Influenza A/H3 accounted for 95% of all lab-confirmed cases in PEI in 2016-17.
  • Our seasonal total was 208 lab-confirmed cases (2 A/pH1N1, 198 A/H3, 3 A/unsubtyped, 5 B).
  • The median age of cases was 63 years with 52% being female.
  • In total there were 88 hospitalizations including 11 ICU patients.

 

Epidemiological curve of laboratory data

Sporadic influenza activity in PEI started in late-October, but the sustained activity did not occur until early January. Influenza A/H3 predominated the season on PEI accounting for 95% of all lab-confirmed cases in PEI. Flu activity peaked in late February and overall the 2016-17 season saw greater than average flu activity. The median age of cases was 63 years and this ranged from <1 to 99 years. Overall, 52% of all lab-confirmed cases were diagnosed in females. Flu activity ended in May, but sporadic cases of influenza may occur at any time during the year.

Lab-confirmed Influenza cases in PEI for the 2016-17 Season

*Lab-confirmed influenza tests are just an indication of greater influenza activity as many individuals with influenza do not seek medical attention.

Positive influenza test results, cumulative 2016-17 season

Influenza A/H3 accounted for 95% of all lab-confirmed cases in PEI in 2016-17.  

Lab-confirmed cases

Cumulative 2016-17

Influenza A

203

A/pH1N1

2

A/H3

198

A/unsubtyped

3

Influenza B

5

Total Influenza

208

There were very few Influenza B lab-confirmed cases during the 2016-17 season in PEI.

 

Respiratory outbreaks, cumulative 2016-17 season

There were 17 respiratory outbreaks reported to the Chief Public Health Office.  Of the outbreaks, 13 were Influenza A/H3 and four were influenza-like illness.  The outbreaks occurred in January, February, and March.

Respiratory Outbreaks

Cumulative 2016-17

Influenza A

13

A/pH1N1

0

A/H3

13

A/unsubtyped

0

Influenza B

0

Influenza-like Illness

4

Other Respiratory

0

Total Outbreaks

17

Outbreaks are defined based on the Fluwatch definitions.

 

Severe outcome surveillance

Hospitalization data is gathered through infection prevention and control practitioners at each Island hospital. There were 88 hospitalizations which included 11 ICU cases during the 2016-17 influenza season. The median age of hospitalized patients was 74 years (mean: 69 years) and this ranged from 2 to 97 years. Hospitalized patients were more likely to be female (52%).

The average length of stay for hospitalized patients was 13 days (median 5 days) and this ranged from 1 to 84 days in hospital.

There was chronic disease information for 84 cases. Of these, 79% had at least one chronic condition. In total, 59% of individuals with chronic conditions had multi-morbidities or more than 1 chronic condition. The most common chronic condition listed was Chronic Obstructive Pulmonary Disease (38%), followed by Diabetes (32%) and Coronary Artery Disease (24%).

Severe Outcome

Cumulative 2016-17

Hospitalizations

88

ICU

11

Deaths

5

Deaths are only reported when there is a positive influenza laboratory test. However, influenza may not have been the major contributing cause of death.

 

Historical influenza seasons

The predominant strain of circulating influenza changes year-to-year. The strain of influenza can impact the severity of disease, the age group(s) affected, and the number of individuals presenting themselves to the health system for care. In addition, the request for influenza testing varies season-to-season.

Influenza Season

Predominant Strain

All Cases*

Hospitalized**

ICU

2011-12

B

53

11

0

2012-13

A/H3

124

54

6

2013-14

A/pH1N1

119

62

13

2014-15

A/H3 (B)

209

98

11

2015-16

A/pH1N1

71

39

2

2016-17

A/H3

208

88

1

*Laboratory confirmed cases. Note that clinical diagnosis of influenza takes place frequently in the community during peak season and is not confirmed with laboratory testing.

**Hospitalized counts include those admitted to ICU.

 

Published date: 
June 6, 2017
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