Ships and stations should monitor influenza trends in their supported populations and be prepared to implement control measures early in the event of an outbreak. Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE) is a valuable and powerful tool to supplement surveillance activities and can be used to monitor and identify outbreaks on multiple platforms within an area of responsibility. A pre-built Respiratory Disease Dashboard in ESSENCE can be obtained from the nearest NEPMU. For more information on ESSENCE, visit NMCFHPC’s Medical Surveillance and Reporting page.

Various commands in the Defense Health Agency produce reports for specific populations that may inform local Navy and Marine Corps medical surveillance activities. These include:
 

• DOW Global, Laboratory-based, Respiratory Surveillance Program: https://www.health.mil/Military-Health-Topics/Health-Readiness/AFHSD/Reports-and-Publications/Respiratory-Summary-and-Reports
• Armed Forces Health Surveillance Division: https://www.health.mil/Military-Health-Topics/Health-Readiness/AFHSD/Integrated-Biosurveillance/Alert-and-Response-Operations

Active molecular surveillance through the WHO’s  Global Influenza Surveillance and Response System looks for new strains of influenza. It is conducted in many countries throughout the world to guide the development of each year’s vaccine components. Within DoW, influenza strain distribution is monitored through Global Emerging Infections Surveillance (GEIS), which funds a network of global research laboratories. A description of DoW-GEIS respiratory surveillance activities was recently published in MSMR:  Beyond the Clinic: The Importance of DoD Viral Respiratory Panel Testing for Public Health Surveillance. The primary influenza sequencing laboratory is the DoW Global Respiratory Pathogen Surveillance Program (*CAC Required*)

Managing an Outbreak

Despite near-complete immunization of active-duty forces, outbreaks of influenza are not uncommon in high-risk settings (e.g., ships, training environments). Widespread travel can introduce out-of-season outbreaks, and occasionally the circulating strain differs enough from the vaccine strain to decrease effectiveness. 

Recommended actions to respond to an influenza outbreak include:
 

• Initiate enhanced surveillance for febrile respiratory illness; a line list should be prepared and populated with confirmed and suspected cases.
• Ensure appropriate clinical testing is being conducted; lab should be advised to send several specimens for full virus characterization.
  •  DoD Global Respiratory Pathogen Surveillance Program (*CAC Required)
  •  Influenza Specimen Collection
• Consider initiating influenza vaccination if the population is unvaccinated (e.g., newly arrived accessions); acceleration of routine vaccinations may be indicated in training environments.
• Institute non-pharmacologic interventions to reduce spread, including enhanced hygiene measures and isolation of ill personnel. Specific resources:
  • USW (P&R) Force Health Protection Guidance-Coronavirus Disease 2019 and Other Infections Respiratory Diseases
  • Fleet Respiratory Guide  (*CAC Required*)
  • Army TG-314 Non-vaccine Recommendations to Prevent Acute Infectious Respiratory Disease (*CAC Required*)
• Report outbreaks through DRSi (see Reporting).
• In high-risk training settings or ships, consider initiating Tamiflu (Oseltamivir) for chemoprophylaxis. Note that the chemoprophylaxis dose (75 mg once per day) is half the treatment dose (75 mg twice per day) and should be sustained for 7 days after the onset of the last case in the affected cohort. 
• Contact local Preventive Medicine (if available) for support.  The cognizant  Navy Environmental and Preventive Medicine Unit (NEPMU) can advise or assist with  outbreak investigations in operational or training settings.

Epidemiology and Selected Publications

Aquino, T. L., Brice, G. T., Hayes, S., Myers, C. A., McDowell, J., White, B., ... & Johnston, D. (2014). Influenza outbreak in a vaccinated population—USS Ardent, February 2014. Morbidity and Mortality Weekly Report, 63(42), 947.

Mazumder, Abir; Ray, Sougat1; Bhaskar, Vijay2; Anand, Kavita B3,; Kumar, B Vijay4. Postexposure Prophylaxis with Oseltamivir in Outbreak Control of pH1N1 Influenza Onboard a Naval Warship: An Observational Study. Journal of Marine Medical Society 22(2):p 123-127, Jul–Dec 2020. | DOI: 10.4103/jmms.jmms_19_20

Pollett S, Hone E, Richard SA, Schmidt K, Simons MP, Wayman M, Tant R, Rothenberg J, Hogan V, O’Connell R, Burgess T, Fries AC, Tilley D, Colombo RE. P-724. The epidemiology, phenotype, and phylogeny of an influenza A/H3N2 virus outbreak among vaccinated U.S. Navy midshipmen. Open Forum Infect Dis. 2025 Jan 29;12(Suppl 1):ofae631.920. doi: 10.1093/ofid/ofae631.920. PMCID: PMC11776750.

Sanchez JLCooper MJ, Myers CA, Cummings JF, Vest KG, Russell KL, Sanchez JL, Hiser MJ, Gaydos CA.2015.Respiratory Infections in the U.S. Military: Recent Experience and Control. Clin Microbiol Rev 28:.https://doi.org/10.1128/cmr.00039-14