County of San Diego INFLUENZA WATCH · 65+ 342 87 68 97 65 70 14 25 58 14 4 9 8. Page 1 of 3 Epidemiology and Immunization Services Branch (619) 692-8499 [email protected]

Table 1. Influenza Surveillance Indicators.

Surveillance Indicator

2017-18

Season

2016-17

Season

Prior 3-

Season

Average*

Influenza detections reported (all types)* 20,833 6,827 6,834

Number of influenza-related ICU cases 320 107 128

Number of influenza-related deaths reported 342 87 84

Number of influenza-related outbreaks reported 117 35 43Season= July 1-June 30

* Includes the 2014-15, 2015-16, and 2016-17 seasons.

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April 30, 2014 Week #17, ending 4/26/14

The purpose of the weekly Influenza Watch is to summarize current influenza surveillance in San Diego County. This summary report reflects the 2017-18 season data.

INFLUENZA WATCHCounty of San Diego

Highlights• Earlier season with record high volume of influenza detections reported. • Predominantly an Influenza A season. • Influenza A/H3 was the main influenza A subtype circulating. • High number of influenza-related deaths, including two pediatric deaths. • Majority of deaths were 65 years of age or older, with underlying conditions.

Epidemiology and Immunization Services Branch(619) 692-8499 [email protected]

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20,833 Total Cases

Seas

on

Su

mm

ary

20

17

-18

320ICU Cases

342Deaths†

Report ContentsPage 1: Overview & IndicatorsPage 2: Virus CharacteristicsPages 3-8: Trend graphsPage 8: Reporting Information

Virus Characteristics

PUBLIC HEALTH SERVICES

117Outbreaks*

August 31, 2018Volume 17, Issue 31

2017-18 Season SummaryJuly 1, 2017 – June 30, 2018

* At least one case of laboratory-confirmed influenza in a setting experiencing ≥2 cases of influenza like illness (ILI) within a 72-hour period.

63.0%

0.3%

2.8%

32.7%

0.2%0.1% 0.9%

Influenza A

Influenza A (H1N1)pdm09

Influenza A (H3) Seasonal

Influenza B

Influenza B/Yamagata

Influenza B/Victoria

Influenza A/B

† Including 44 deaths less than 65 years of age, reportable to CDPH.

mailto:[email protected]

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April 30, 2014 Week #17, ending 4/26/14


Page 2 of 10PUBLIC HEALTH SERVICES

Table 2. Influenza Detections Reported, 2017-18.

Positive Test Type/Subtype Count Percent

Influenza A 13,128 63.0%

Influenza A (H1N1)pdm09 62 0.3%

Influenza A (H3) Seasonal 593 2.8%

Influenza B 6,811 32.7%

Influenza B/Yamagata 42 0.2%

Influenza B/Victoria 19 0.1%

Influenza A/B 178 0.9%

Total 20,833 100%



0

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27 29 31 33 35 37 39 41 43 45 47 49 51 1 3 5 7 9 11 13 15 17 19 21 23 25

Nu

mb

er

of

Ca

se

s

Week Number

Figure 1. San Diego County Influenza Detections by Type and Week of Report, 2017-18 (N=20,833).

Influenza A Influenza A(H1N1)pdm09 Influenza A(H3) Influenza B Influenza B/Victoria Influenza B/Yamagata Influenza A/B



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Influenza Activity Indicator: The activity levels compare the number of reported influenza cases for the current week to the mean (and number of standard deviations above of the mean) of the reported influenza cases during non-influenza season weeks (CDC disease weeks 27-39). There are 10 activity levels, classified as: minimal (levels 1-3), low (levels 4-5), moderate (levels 6-7), and high (levels 8-10). An activity level of 1 corresponds to a week having a number of reported influenza cases that is below the mean; level 2 corresponds to the number of reported influenza cases as less than 1 standard deviation above the mean; level 3 corresponds to the number of reported influenza cases as more than 1 but less than 2 standard deviations above the mean, and so on, with an activity level of 10 corresponding to the number of reported influenza cases at 8 or more standard deviations above the mean.

The number of reported influenza cases was at a “High” level for 26 consecutive weeks (weeks 44-17) during the 2017-18 season in San Diego County.

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Flu

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Week Number

Figure 2. Influenza Activity Level: Number of Influenza Cases Reported.

|--

--M

inim

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---L

ow

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Mo

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rate

-|--

---H

igh

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Activity Level

Legend



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0

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25,000

27 29 31 33 35 37 39 41 43 45 47 49 51 1 3 5 7 9 11 13 15 17 19 21 23 25

Cum

ulat

ive

Num

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of R

epor

ts

Week Number

Figure 3. Cumulative Influenza Case Reports by Episode Week & Season.

2017-18 2016-17 2015-16 2014-15 2013-14

2012-13 2011-12 2010-11 2009-10 2008-09

0

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<1 1-9 yrs 10-19 yrs 20-39 yrs 40-59 yrs 60-79 yrs 80+

Perc

ent o

f Cas

es

Age Group

Figure 4. Percent of Reported Influenza Cases by Age Group and Season, 2013-14 to 2017-18.

2013-14

2014-15

2015-16

2016-17

2017-18



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024

68101214

27 34 41 48 3 10 17 24 31 38 45 52 7 14 21 28 35 42 49 3 10 17 24 31 38 45 52 7 14 21 28 35 42 49 4 11 18 25 32 39 46 1 8 15 22Percent of Emergency Department Visits

Figure 5. Percent of San Diego County Emergency Department Visits for Influenza-like Illness by Week and FY Compared to 5-Year Baseline & Upper 95% Threshold Values (Serfling Method)

ILI% Baseline Upper 95% Threshold2012-13 2013-14 2014-15 2015-16 2016-17 2017-18




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27344148 3 10172431384552 7 142128354249 3 10172431384552 7 142128354249 4 111825323946 1 8 1522

Perc

ent o

f Em

erge

ncy

Dep

artm

ent

Visi

ts

Figure 5. Percent of San Diego County Emergency Department Visits for Influenza-like Illness by Week and Season Compared to 5-Year Baseline

& Upper 95% Threshold Values (Serfling Method).

ILI% Baseline Upper 95% Threshold

2012-13 2013-14 2014-15 2015-16 2016-17 2017-18

0

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27 41 3 17 31 45 7 21 35 49 10 24 38 52 14 28 42 4 18 32 46 8 22

Perc

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f Dea

ths

Figure 6. Percent of San Diego County Deaths Registered with Pneumonia and/or Influenza by Week and Season Compared to Prior 5-

Year Baseline & Upper 95% Threshold Values (Serfling Method).

%P&I Deaths Baseline Upper 95% Threshold

2012-13 2013-14 2014-15 2015-16 2016-17 2017-18


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ber

of D

eath

s

Season

Figure 7. Influenza Deaths by Type and Season

Both Influenza A and Influenza B

Influenza A/B, Type Unknown

Influenza B

Pandemic H1N1

Influenza A/H3

Influenza A, No Subtype

68

97

7065

1425

342

58

9 8

87

414

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-18

Num

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of D

eath

s

Season

Figure 8. Influenza Deaths by Age and Season

<1 yr

1-17

18-34

35-64

65+

342

8768

97

7065

1425

58

89414


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80

27 29 31 33 35 37 39 41 43 45 47 49 51 1 3 5 7 9 11 13 15 17 19 21 23 25

Num

ber

of IC

U C

ases

Episode Week

Figure 10. Number of Influenza Cases Requiring ICU Care by Episode Week and Type of Influenza, 2017-18 (N=320).

Influenza A/B Influenza A Influenza A(H1N1)pdm09 Influenza A(H3) Influenza B Influenza B/Victoria Influenza B/Yamagata

Note: Episode week is the week of symptom onset, or earliest available date in which the case is identified.


50%

19%

35% 33%

100%

88%

98% 96%

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100

< 18 years 18-64 years 65+ years Total

Perc

ent o

f Dea

ths

Figure 9. Percent of Influenza Deaths Fully Vaccinated* and With Underlying Conditions by Age Group, 2017-18.

Vaccinated Underlying Condition* known vaccinated

N=2 N=42 N=298 N=342


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27 29 31 33 35 37 39 41 43 45 47 49 51 1 3 5 7 9 11 13 15 17 19 21 23 25

Perc

enta

ge o

f ED

vis

its

Week Number

Figure 12. Percent Emergency Department ILI Visits by Age Group, 2017-18

0-19 Yrs 20-29 Yrs 30-39 Yrs 40-49 Yrs 50-59Yrs 60+ Yrs


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isits

Week Number

Figure 11. Percent of Emergency Department Visits for ILI Chief Complaint by Week, 2016-17 & 2017-18.

2017-18 2016-17


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* Influenza vaccinations administered and entered into the San Diego Immunization Registry (SDIR)

0

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ulat

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of In

fluen

za V

acci

nes

Week Number

Figure 14. Cumulative Number of Influenza Vaccinations Administered* by Week and Season.

2017-18 2016-17

2016 -17 Total: 601,139

2017-18 Total: 770,069

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of In

fluen

za V

acci

nes

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Figure 13. Number of Influenza Vaccinations Administered* by Week and Season.

2017-18 2016-17





https://www.sandiegoimmunizationregistry.org/sdir_home.htm

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Influenza Surveillance in San Diego County

San Diego County Public Health Services’ Epidemiology Program conducts year round influenza surveillance. Please contact us with questions at (619) 692-8499 or by email to: [email protected]. Local providers are encouraged to report laboratory positive influenza detections to the County Epidemiology Program by FAX (858) 715-6458. Please fax a Case Report Form and/or a printed laboratory result, and indicate if the patient was admitted to ICU or died, and/or is a resident of a congregate living facility.

For questions regarding sending specimens to Public Health Laboratory (PHL), call (619) 692-8500. Click here for the updated PHL PCR Test Request Form.

Click here to subscribe to the weekly Influenza Watch emails (sent during the season only). Visit the County of San Diego Immunization Program website for vaccination updates and resources: www.sdiz.org.




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ith

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mpl

aint

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Figure 15. Percent of Emergency Department Visit Chief Complaints for Cough, Cold, Fever, or Respiratory Symptoms by Week, 2017-18.

Cough Cold Symptoms Fever Respiratory Symptoms



http://www.sdcounty.ca.gov/hhsa/programs/phs/documents/FluCaseReportForm.pdf

https://www.sandiegocounty.gov/content/dam/sdc/hhsa/programs/phs/documents/SD_County_Test_Req.pdf

https://public.govdelivery.com/accounts/CASAND/subscriber/new?topic_id=CASAND_328

http://www.sdiz.org/

Documents

County of San Diego INFLUENZA WATCH · 65+ 342 87 68 97 65 70 14 25 58 14 4 9 8. Page 1 of 3 Epidemiology and Immunization Services Branch (619) 692-8499 [email protected]