Week ending 20 January 2018 (week 3)

Flu continues to rise in week 3, and it is still too early to determine if this season has peaked. There was an increase of 35% in positive influenza B specimens and a 10% in-crease in influenza A specimens since week 2. This pattern of gaining influenza B cases is typically seen in the latter part of flu seasons, though according to the World Health Organi-zation (WHO), several Northern Hemisphere countries have reported early, brisk influenza B activity. Since last week, the number of influenza-associated hospitalizations has increased 30% with a total of 18 reports. Recommendations are still in place to wash hands frequent-ly, get vaccinated and vaccinate children, avoid close contact with sick people, and seek treatment within 48 hours of symptom onset.

Additional Resources: Army Influenza Reports; ARD Reports; AFHSC Influenza Reports; NHRC FRI Reports;

DoD Global Influenza Surveillance Program; DoD Pandemic Influenza Watchboard; CDC

Key: ILI-Influenza-Like Illness; DRSi- Disease Reporting System Internet; NHRC- Naval Health Research Center;

ADV-Adenovirus; RSV-Respiratory Syncytial Virus; DED- Disease Epidemiology Division; SM-Service Member

Questions? Email APHC DEP 410-436-7605

*Data Source: MEDPROS, ASIMS, MRRS

INFLUENZA-ASSOCIATED HOSPITALIZATIONS

DEMOGRAPHICS

Influenza Vaccination

Coverage* As of 25 January 2018

N/A DoD

95% Army Active Duty

87% Army Guard

79% Army Reserve

SUMMARY

AD: In week 3, there was a total of 281 positive respiratory

illness specimens from Active Duty (AD) Service Members;

50% (140) from individuals in the 18-29 age group, followed

by 33% (92) in the 30-39 age group, 13% (39) in the 40-49

age group, 3% (9) in the 50-59 age group, and one 60+.

Non-AD: A total of 1477 positive respiratory illness speci-

mens were among non-AD beneficiaries, with the majority of

specimens from individuals under the age of 18 (60%, 880).

In week 3, widespread influenza activity was reported to the

CDC by Puerto Rico and 49 states. Regional activity was re-

ported by Guam, local activity was reported by the District of

Columbia and Hawaii, and the US Virgin Islands reported

sporadic activity.

In the military population, ten (56%) hospitalizations were

reported from RHC-C, five (28%) from RHC-P, and three

(16%) from RHC-A.

In week 3, 18 influenza-associated hospitalizations were re-

ported in DRSi; 15 non-AD individuals and 3 AD. The ages of

the hospitalized individuals ranged from <1 to 63 years old*.

Ten cases (56%) were not vaccinated, and four (22%) were

vaccinated. In the same week last year, three cases were

reported in DRSi. This season there has been a total of 64

hospitalizations; 54 non-AD and 10 AD. By this time last sea-

son, twenty hospitalizations were reported in DRSi.

*DRSi does not capture cases older than 65 years old for influenza-associated hospitalizations.

Click to enlarge image GEOGRAPHIC SPREAD

Week ending 20 January 2018 (week 3) Army Influenza Activity Report U.S. Army Public Health Center

LABORATORY RESPIRATORY SPECIMEN TESTING

ILI ACTIVITY - ARMY ILI ACTIVITY - UNITED STATES

In week 3, 38% (1758) of specimens tested posi-

tive for a respiratory pathogen. Influenza A and B

accounted for 78% and 18% of the positive spec-

imens, respectively. RSV accounted for 3% of

positive specimens. The majority of positive re-

sults for influenza A were from rapid antigen

tests (RAT), with 80% of all positive influenza A

tests being RAT tests. Ft Hood performed the

most RAT tests, followed by Ft Benning and Ft

Bliss. Ft Belvoir performed 9 cultures, 8 PCRs,

and 75 RAT tests for influenza A.

Nationwide, 84.2% of positive specimens were from influenza A/H3N2, and 15.8% were from influenza B in week 3. In

the Army population, 1374 of 4005 (34.3%) specimens tested positive for influenza A, a decrease of 0.2% from week 2. 1136 (83%) of the positive influenza A specimens were from non-active duty individuals. RHC-C and RHC-A reported the

majority of positive influenza-A specimens, with 745 (54%) and 541 (39%) of the total influenza-A positive specimens.

Nationwide in week 3, incident ILI activity was 6.6%, above the national baseline of 2.2%. Regionally, the percentage of

ILI outpatient visits reported to the CDC ranged from 2.9% to 11.7%. In the Army population, incident ILI activity was 7% lower than the same time last year. The majority of ILI encounters (72%) were from non-AD patients.

Locations providing week 3 laboratory data as of 23 January 2018: Korea, Ft Belvoir (NCR), Ft Benning, Ft Bliss, Ft Bragg, Ft Campbell, Ft

Carson, Ft Drum, Ft Gordon, Ft Hood, Ft Huachuca, Ft Irwin, Ft Jackson, Ft Knox, Ft Leavenworth, Ft Lee, Ft Leonard Wood, Ft Meade, Ft Polk, Ft

Riley, Ft Sam Houston, Ft Sill, Ft Stewart, Ft Wainwright, Landstuhl, Redstone Arsenal, Tripler, West Point, and Walter Reed.

*NOTE: Madigan AMC data was not received due to the switch from AHLTA/CHCS to MHS Genesis

Week ending 20 January 2018 (week 3) Army Influenza Activity Report U.S. Army Public Health Center

Regional Health Command - Atlantic (RHC-A)

Regional Health Command - Central (RHC-C)

Regional Health Command - Europe (RHC-E)

Regional Health Command - Pacific (RHC-P)

Proportion of Influenza A Positive Specimens by Week and Region, Army Medical Laboratories, 2017-2018 as Compared to 2014-2017

Note: Reportable influenza cases are defined as only cases that have been hospitalized and are under the age of 65. See Armed Forces Reportable Medical Events Guidelines and Case Definitions for more information Data as of 25 January 2018.

Clinic visits for ILI are obtained from ESSENCE. Data as of 25 January 2018.