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2018/19 Influenza Season Data

The Pennsylvania Department of Health monitors influenza activity throughout the year but ramps up surveillance activities in the fall and winter. The official influenza surveillance season starts with the 40th week of the year (typically around the beginning of October) and ends on the 20th week of the following year (in May). For the 2018-2019 season, the influenza surveillance season began on Oct. 1, 2018, and will run through May 19, 2019. Updated influenza activity data will be posted on this web page every Tuesday throughout the influenza surveillance season. These updates will provide a summary on:

  1. When and where influenza activity is occurring;
  2. Current trends in influenza as compared to previous seasons; and
  3. What types and subtypes of influenza viruses are currently circulating. 

It is important to note that the influenza case counts presented on this page are restricted to only those cases that have had a positive laboratory test for flu (by rapid test, DFA, PCR or culture) reported to the PADOH. These case counts represent only a fraction of the actual burden of illness due to influenza occurring in the commonwealth at any given time. This is because most persons with influenza do not go to the doctor or are not tested or reported. Influenza spread and severity varies widely from season to season. It is estimated that five to 20 percent (600,000 to 2,400,000) of Pennsylvanians get the flu each year, and 120 to 2,000 die from complications of influenza.

Flu Activity Code: WIDESPREAD (week 6 ending 2/9/2019)

*The flu activity code is a characterization of the geographic spread of influenza in Pennsylvania. It does not indicate how severe the influenza season is. Rather, it indicates how much of Pennsylvania is experiencing influenza activity. The level of activity is classified based on CDC definitions below, which are used by all 50 states to characterize influenza activity.

No Activity No laboratory-confirmed cases of influenza and no reported increase in the number of cases of ILI.
SPORADIC Small numbers of laboratory-confirmed influenza cases or a single laboratory-confirmed influenza outbreak has been reported, but there is no increase in cases of ILI
LOCAL Outbreaks of influenza or increases in ILI cases and recent laboratory-confirmed influenza in a single region of the state
REGIONAL Outbreaks of influenza or increases in ILI and recent laboratory confirmed influenza in at least two but less than half the regions of the state, with recent laboratory evidence of influenza in those regions
WIDESPREAD Outbreaks of influenza or increases in ILI cases and recent laboratory-confirmed influenza in at least half the regions of the state, with recent laboratory evidence of influenza in the state

Influenza surveillance data presented below reflect influenza activity during the time period referred to above. Data may change from week to week as numbers are adjusted for late reporting, misclassification of cases, and errors in classifying county or state of residence.

Pennsylvania Weekly Influenza Report
Summary:

Flu activity has increased during the past week in all state regions. The activity is higher than epidemic threshold. Highest activity was reported in the Southeast and Northwest regions.

The code for the geographic spread is 'Widespread' for week 6 that ended on 2/9/2019.

A total of 30,592 laboratory-confirmed influenza cases have been reported season to date. Confirmed reports were received from 67 Counties out of the 67 Counties.

Percent of outpatient visits associated with Influenza-Like Illness (ILI) has been high and is still higher than the epidemic threshold for the State regions.

There are 36 adult flu associated deaths reported season-to-date.

There are no influenza-associated pediatric deaths reported this week. There has been one influenza-associated pediatric death reported this season.


Confirmed Influenza Laboratory Tests Received by PA DOH Surveillance

Table 1. Influenza Cases (positive by rapid test, PCR, or culture) Reported in Pennsylvania, 9/30/2018 to 2/9/2019 (n=30,592) - Cases by County and Influenza Type*   
 
5CountyInfluenza TypeTOTAL

ABU**
 
61
6
0
67
ADAMS177
70
184
ALLEGHENY1364
50
1101524
ARMSTRONG
1782
0
180
BEAVER
410520435
BEDFORD118110
189
BERKS1584191
1604
BLAIR
25811
0
269
BRADFORD2580
0
258
BUCKS942370
979
BUTLER214320
246
CAMBRIA373211395
CAMERON2750
32
CARBON
2741
0
275
CENTRE
486550
541
CHESTER
916171
934
CLARION1063
0
109
CLEARFIELD
4996
0
505
CLINTON
91
2
0
93
COLUMBIA28050
285
CRAWFORD4053
0
408
CUMBERLAND524210
545
DAUPHIN
509200
529
DELAWARE
153334
51572
ELK
1540
0
154
ERIE311100
321
FAYETTE
2214
0
225
FOREST40
0
4
FRANKLIN
1940
0
194
FULTON
971
0
98
GREENE
1602
0
162
HUNTINGDON
2061
0
207
INDIANA19460
200
JEFFERSON303
100
313
JUNIATA
220
0
22
LACKAWANNA855110
866
LANCASTER
750171768
LAWRENCE1432
0
145
LEBANON
5160
0
516
LEHIGH
15023641
1579
LUZERNE
1617120
1629
LYCOMING
5233
0
526
MCKEAN
1272
0
129
MERCER
1112
0
113
MIFFLIN13540
139
MONROE
5781
0
579
MONTGOMERY233390182441
MONTOUR441
0
45
NORTHAMPTON1581561
1638
NORTHUMBERLAND37410
375
PERRY
653
0
68
PHILADELPHIA
1668241
1693
PIKE
860
0
86
POTTER82150
97
SCHUYLKILL40371
411
SNYDER14980
157
SOMERSET1098
2
119
SULLIVAN2
0
0
2
SUSQUEHANNA1080
1
109
TIOGA
820
0
82
UNION
9050
95
VENANGO
420
0
42
WARREN
700
0
70
WASHINGTON441252
468
WAYNE294320
326
WESTMORELAND494250
519
WYOMING
830
0
83
YORK669100
679
All2957980720630592

  * Influenza counts are provisional and may change as more information is received.

**Test results may identify influenza Type A, influenza Type B, or influenza without specifying Type A or B. Some tests only give a positive or negative result and can-not identify influenza type.

Figure 1. Number of Pa. Influenza Cases by Week of First Report 

Figure 1. Number of Pa. Influenza Cases by Week of First Report  

Figure 2: Comparison of PA-NEDSS Influenza Cases (All Types) in Current Season to the Eight Previous Seasons

Figure 2: Comparison of PA-NEDSS Influenza Cases (All Types) in Current Season to the Eight Previous Seasons 
                                        

Figure 3: Season-to-date Influenza Sub-Typing Results From State Public Health Lab (n=18) 

Figure 3: Season-to-date Influenza Sub-Typing Results From State Public Health Lab 

 
Table 2: Season-To-Date Influenza-Associated Deaths by Age

Age Influenza-associated Death
0-18 1
19-49 3
50-64 9
65 + 24
All 37

 

Syndromic Surveillance

The Pennsylvania Department of Health's syndromic surveillance system receives data on visits to emergency departments (EDs) from most hospitals in the state.  The system looks at the reason for visiting the ED and determines if ED visits were likely due to influenza-like illness (ILI). The graph displays ED visits due to ILI as a percentage of total ED visits. This provides yet another way for the Department of Health to monitor influenza and ILI in the state. 

Figure 4: season-to-date Influenza-Like Illness (ILI) Emergency Visits

Figure 4: season-to-date Influenza-Like Illness (ILI) Emergency Visits


Figure 5: season-to-date Influenza-Like Illness (ILI) Emergency Visits by community health districts  
Figure 5: season-to-date Influenza-Like Illness (ILI) Emergency Visits by community health districts

Figure 6: season-to-date Influenza-Like Illness (ILI) Emergency Visits by age groups

Figure 6: season-to-date Influenza-Like Illness (ILI) Emergency Visits by age groups

World Health Organization (WHO) and National Respiratory & Enteric Virus Surveillance System (NREVSS) Collaborating Laboratories

Thirteen clinical virology laboratories in Pa. are WHO and/or NREVSS collaborating laboratories for influenza surveillance.

These labs report weekly the number of respiratory specimens tested and the number positive for influenza types A and B to CDC. Some labs also report the influenza A subtype (H1 or H3) and influenza B lineage (Victoria or Yamagata). Because denominator data is provided, the weekly percentage of specimens testing positive for influenza is calculated.

Figure 7: Influenza Test Results Reported to the National Respiratory and Enteric Virus Surveillance System (NREVSS) Select Pennsylvania Laboratories, Season to date

Figure 7: Influenza Test Results Reported to the National Respiratory and Enteric Virus Surveillance System (NREVSS) Select Penn