Back to Top Skip to main content

Amid COVID-19, seasonal influenza still a threat to force readiness

Hospital Corpsman administers a flu shot to a navy officer. The flu shot helps DoD members maintain both mission readiness and wellness. (U.S. Navy photo by Mass Communication Specialist 2nd Class Marc Cuenca/Released)

Recommended Content:

Coronavirus | Influenza Summary and Reports | Immunization Healthcare | Vaccine-Preventable Diseases | Influenza, Southern Hemisphere

The COVID-19 pandemic has emerged as the most significant public health emergency in this century. As individuals around the globe race for treatment options and take preventive measures against COVID-19, those living in the Southern Hemisphere are also preparing for another virus – seasonal influenza. The flu typically takes hold from April through September in the Southern Hemisphere and impacts service members and their beneficiaries on military orders in places south of the equator, such as New Zealand, Australia, southern parts of Africa and South America as well as Indonesia.

Before 2020, a Federal Drug Administration-approved Southern Hemisphere influenza vaccine was not available for military personnel or beneficiaries. Service members received the Northern Hemisphere flu vaccine during the Northern Hemisphere season, which runs October to March.

Once the FDA approved a Southern Hemisphere influenza vaccine, the combatant commands quickly engaged with the Office of Assistant Secretary of Defense for Health Affairs’ Health Readiness Policy and Oversight and Defense Health Agency to get access for their personnel.

Through joint efforts by the CCMDs, Defense Logistics Agency, U.S. Army Medical Materiel Agency, and DHA’s Immunization Healthcare Division, service members and their beneficiaries in the Southern Hemisphere can access the FDA-approved, U.S.-labeled Southern Hemisphere vaccine Fluzone®.

“The vaccination will be made available at designated medical treatment facilities in May 2020,” according to Tara Reavey, chief of policy and program management for DHA's Immunization Healthcare Division.

Access to both Northern and Southern hemisphere influenza vaccines supports troop readiness since different flu strains circulate in each hemisphere. “Symptoms of the Northern Hemisphere and Southern Hemisphere seasonal influenzas are similar,” said Dr. Jay Montgomery, medical director of the Immunization Healthcare Division’s North Atlantic Region Vaccine Safety Hub. “Typical flu symptoms include fever, cough, sore throat, runny nose, and muscle aches, but in severe cases may result in hospitalization or death.”

However, Montgomery added, “the common strains identified in the Northern and Southern Hemisphere differ about 60% of the time.” He said the challenge to support force readiness became apparent as DoD members experienced flu-like symptoms when traveling to the Southern Hemisphere flu zone after receiving the Northern Hemisphere vaccine.

“Obviously if we don't have the right virus strains in the vaccine, people are not going to get protection against those strains,” said Montgomery. “Over the years, a substantial number of influenza-like illnesses have occurred among service members and other DoD personnel participating in multinational exercises, such as in Australia, every year,” he said, adding that a vaccine targeting Southern Hemisphere influenza should result in a decrease of influenza-like illnesses there.

The DHA-Interim Procedures Memorandum 20-002 for Southern Hemisphere influenza was published March 20 and “aligns with Centers for Diseases Control and Prevention recommendations to use the appropriate influenza vaccine,” said Reavey. Specifically, Southern Hemisphere influenza vaccination is required for all active duty, reserve component, National Guard members (and recommended for all other beneficiaries), permanently or temporarily assigned for at least 14 contiguous days between April 1 and Sept. 30 to an area designated as a Southern Hemisphere influenza zone by the World Health Organization.

U.S. government civilian employees and family members of personnel who are living in or conducting a permanent change of station to the Southern Hemisphere are authorized to receive the Southern Hemisphere vaccine. In order to develop adequate immunity, personnel traveling to the Southern Hemisphere between April and September should be vaccinated at least two weeks before they go to the region, if possible.

DoD personnel traveling to or residing in the Northern Hemisphere for at least 14 days between October and March and who have not received the current seasonal Northern Hemisphere influenza vaccine are required to receive a Northern Hemisphere vaccine in accordance with the most current DHA-IPM for the Northern Hemisphere seasonal influenza vaccination program.

The DHA-IPM states that individuals may receive vaccines for both the Northern Hemisphere flu and the Southern Hemisphere flu in a year span, but the immunizations will need to be given at least 28 days apart. Service members will not need to receive a flu vaccine for either hemisphere when traveling to the area during an offseason and if in the region for less than 14 days.

For more information on the Southern Hemisphere influenza vaccine, please visit the Military Health System Influenza webpage.

You also may be interested in...

Is It Your Time to Get the COVID-19 Vaccine?

This graphic informs TRICARE beneficiaries which tier they fall into as their local military treatment facility or clinic offers the vaccine.

This Infographic informs TRICARE beneficiaries which tier they fall into as their local military treatment facility or clinic offers the vaccine.

Recommended Content:

Coronavirus | COVID-19 Vaccine Efforts

Genetic sequence data for SARS-CoV-2

Infographic describing how DoD was able to conduct genome sequencing on the COVID-19 virus

Genetic sequence data for SARS-CoV-2, the virus that causes #COVID19, plays a vital role in force health protection efforts within the DoD. To jumpstart sequencing efforts, the Armed Forces Health Surveillance Branch's Global Emerging Infections Surveillance and Response applied a collaborative approach to sequencing capabilities. Resulting sequence data will provide critical information about transmission patterns, track diagnostic effectiveness, and guide the development and evaluation of medical countermeasures.

Recommended Content:

Armed Forces Health Surveillance Branch | Coronavirus | Global Emerging Infections Surveillance

DoD Flu VE

DoD Flu VE

Each season, several entities within the(DoD) perform surveillance for influenza among beneficiaries and utilize these data to perform VE analyses to estimate how well the seasonal vaccine protects against medically-attended influenza.

Recommended Content:

Health Readiness | Armed Forces Health Surveillance Branch | Epidemiology and Analysis | Medical Surveillance Monthly Report | Public Health | Influenza Summary and Reports

Department of Defense Global, Laboratory-based Influenza Surveillance Program’s Influenza vaccine effectiveness estimates and surveillance trends, 2016 – 2017 Influenza Season

Each year, the Department of Defense (DoD) Global, Laboratory-based Influenza Surveillance Program performs surveillance for influenza among service members of the DoD and their dependent family members. In addition to routine surveillance, vaccine effectiveness (VE) studies are performed and results are shared with the Food and Drug Administration, Centers for Disease Control and Prevention, and the World Health Organization for vaccine evaluation. This report documents the annual surveillance trends for the 2016 – 2017 influenza season and the end-of-season VE results. The analysis was performed by the U.S. Air Force School of Aerospace Medicine Epidemiology Laboratory, and the DoD Influenza Surveillance Program staff at Wright-Patterson Air Force Base, OH. FINDINGS: A total of 5,555 specimens were tested from 84 locations: •	2,486 (44.7%) negative •	1,382 (24.9%) influenza A •	1,093 (19.7%) other respiratory pathogens •	443 (8.0%) influenza B •	151 (2.7%) co-infections The predominant influenza strain was A (H3N2), representing 73.8% of all circulating influenza. Pie chart displays this information. Graph showing the numbers and percentages of respiratory specimens positive for influenza viruses, and numbers of influenza viruses identified, by type, by surveillance week, Department of Defense healthcare beneficiaries, 2016 – 2017 influenza season displays. The vaccine effectiveness (VE) for this season was slightly lower than for the 2015 – 2016 season, which had a 63% (95% confidence interval: 53% - 71%) adjusted VE. The adjusted VE for the 2016 – 2017 season was 48% protective against all types of influenza.  Access the full report in the January 2018 MSMR (Vol. 25, No. 1). Go to:

This infographic documents the annual surveillance trends for the 2016 – 2017 influenza season and the end-of-season vaccine effectiveness.

Recommended Content:

Health Readiness | Influenza Summary and Reports | Medical Surveillance Monthly Report | Vaccine-Preventable Diseases | Force Health Protection | Global Health Engagement

Outbreak of Influenza and Rhinovirus co-circulation among unvaccinated recruits, U.S. Coast Guard Training Center Cape May, NJ, 24 July – 21 August 2016

On 29 July 2016, the U.S. Coast Guard Training Center Cape May (TCCM), NJ, identified an increase in febrile respiratory illness (FRI) among recruits who were unvaccinated against seasonal influenza as a result of the annual vaccine’s expiration. This report characterizes the outbreak and containment measures implemented at TCCM during the outbreak period. In 2016, respiratory infections affected more than 250,000 U.S. service members and comprised approximately 22% of medical encounters among military recruit populations – who are highly susceptible to respiratory infections. Seasonal influenza and rhinovirus are two of the leading respiratory pathogens. During the Surveillance Period: 115 recruits reported respiratory infection symptoms. Pie chart 1 shows the following data: •	41 (35.7%) suspected cases •	74 (64.3%) confirmed cases Among confirmed cases, lab specimens tested positive for: •	Influenza A 34 (45.9%) •	Rhinovirus 28 (37.8%) •	Influenza A and rhinovirus co-infection 11 (14.9%) •	Rhinovirus and adenovirus co-infection 1 (1.4%) Data above depicted in pie chart 2. •	24 July – 6 August, Influenza predominated •	7 August – 20 August, Rhinovirus predominated Although the outbreak significantly affected operations at TCCM, a timely and comprehensive response resulted in containment of the outbreak within 5 weeks. Key Factor for Outbreak Control •	Rapid detection through FRI sentinel surveillance •	Quick decision-making •	Streamlined response by using a single chain of command •	Rapid implementation of both nonpharmaceutical and pharmaceutical interventions Access the full report in the January 2018 MSMR (Vol. 25, No. 1). Go to:

This report characterizes the outbreak and containment measures implemented at the U.S. Coast Guard Training Center Cape May (TCCM), New Jersey, during a July 24 – August 21, 2016 outbreak period.

Recommended Content:

Health Readiness | Medical Surveillance Monthly Report | Integrated Biosurveillance | Influenza Summary and Reports

Mid-season influenza vaccine effectiveness estimates for the 2016 – 2017 influenza season

The Department of Defense (DoD) conducts year-round influenza surveillance for military healthcare beneficiaries and select civilian populations. Data from routine respiratory surveillance are used to estimate mid-season influenza vaccine effectiveness (VE) and these findings are shared at the Food and Drug Administration’s advisory committee meeting on U.S. influenza vaccine strain selection. DoD VE estimates from the Defense Health Agency’s Armed Forces Health Surveillance Branch (AFHSB) and Naval Health Research Center (NHRC) are presented in this report. Findings •	For all influenza types: VE was 42% as found by AFHSB-Air Force Satellite Cell, similar to NHRC’s overall VE of 45% •	Influenza A (H3N2) VE was 42% by AFHSB-AF estimation and VE was 46% as estimated by NHRC •	VE for Influenza B was slightly higher at 53% as estimated by AFHSB-AF •	AFHSB analysis found that VE against influenza A was 3% and VE against influenza A (H3N2) was 33% Table showing the mid-season influenza effectiveness estimates, 2016 –2017 displays. The mid-season influenza VE estimates indicated that vaccination reduced the odds of medically attended influenza infection by approximately 45% among DoD dependents and civilians. Access the full report in MSMR Vol. 24 No. 8 August 2017 at  Three photos display on this infographic: 1.	An elderly woman receiving a flu show from a female service member 2.	Female service member receives a flu shot 3.	Male physician hold a flu shot

This infographic documents Department of Defense mid-season influenza vaccine effectiveness estimates from the Defense Health Agency’s Armed Forces Health Surveillance Branch and Naval Health Research Center for the 2016 – 2017 influenza season.

Recommended Content:

Armed Forces Health Surveillance Branch | Influenza Summary and Reports
Showing results 1 - 6 Page 1 of 1

DHA Address: 7700 Arlington Boulevard | Suite 5101 | Falls Church, VA | 22042-5101

Some documents are presented in Portable Document Format (PDF). A PDF reader is required for viewing. Download a PDF Reader or learn more about PDFs.