Skip main navigation

Military Health System

Clear Your Browser Cache

This website has recently undergone changes. Users finding unexpected concerns may care to clear their browser's cache to ensure a seamless experience.

2023-2024 Mid-Season Influenza Vaccine Effectiveness Against Laboratory-Confirmed Influenza Hospitalizations: U.S. Active Component Service Members

Image of 48088663. This report provides data supporting use of influenza vaccines among typically healthy service members to prevent influenza hospitalization.

This Surveillance Snapshot provides an overview of the 2023-2024 mid-season analysis of influenza VE against influenza hospitalizations among ACSMs. Data from the DMSS and standardized laboratory data provided by DCPH–Portsmouth were utilized for this analysis.1 A cohort study design was implemented among the population of ACSMs in service at any time between September 1, 2023 and February 14, 2024. 

The outcome was defined as a laboratory-confirmed influenza-positive result (rapid antigen, RT-PCR, or culture influenza assay) with an indication that the individual was hospitalized, or a hospitalization record with the first or second diagnostic International Classification of Diseases, 10th revision code for influenza (J09-J11). Person-time started at the beginning of the surveillance period or entry into active component service (whichever came last) and was censored at either the occurrence of the outcome, end of the surveillance period, or leaving active component or military service (whichever came first). Person-time and outcomes were stratified by vaccination status. Person-time and outcomes occurring prior to vaccination and up to 13 days post-vaccination were defined as unvaccinated. Person-time and outcomes occurring at least 14 days after vaccination were defined as vaccinated. Analyses were conducted for laboratory-confirmed influenza hospitalizations alone and then combined with hospitalization records for influenza. Incidence rates per 100,000 person-years (p-yrs) were calculated and a Poisson regression model was used to calculate adjusted incidence rate ratios (adjusted for sex, age category, prior vaccination [any influenza vaccine within previous five years], and month of diagnosis) and 95% CIs. VE was defined as (1 - OR) x 100. 

There were 47 laboratory-confirmed influenza hospitalizations among ACSMs during the study period. An additional 17 influenza hospitalization records were identified using the encounter data. For both outcomes, the incidence rate of influenza hospitalization among unvaccinated ACSMs was twice the rate of vaccinated ACSMs (lab-confirmed only: 1.0 vs. 0.5 per 100,000 p-yrs; lab-confirmed and hospitalization records: 1.4 vs. 0.7 per 100,000 p-yrs) (Table). Likewise, the adjusted analysis resulted in VE estimates of 46% (95% CI: 2, 70) and 54% (95% CI: 12, 72) for the laboratory-confirmed only and laboratory-confirmed with hospitalization records, respectively. 

Click on the table to access a 508-compliant PDF version

The results of this analysis show moderate protection against hospitalization for influenza among ACSMs from the 2023-2024 seasonal influenza vaccines. Although the number of outcomes are small, the analysis still reached statistical significance and provides data supporting the use of influenza vaccines among typically healthy ACSMs to prevent influenza hospitalizations. 

Reference

  1. Rubertone MV, Brundage JF. The Defense Medical Surveillance System and the Department of Defense serum repository: glimpses of the future of public health surveillance. Am J Public Health. 2002;92(12):1900-1904. doi:10.2105/ajph.92.12.1900

You also may be interested in...

Article
Jun 1, 2022

Medical Evacuations out of the U.S. Central and U.S. Africa Commands, Active and Reserve Components, U.S. Armed Forces, 2021

The proportions of evacuations out of USCENTCOM that were due to battle injuries declined substantially in 2021. For USCENTCOM, evacuations for mental health disorders were the most common, followed by non-battle injury and poisoning, and signs, symptoms, and ill-defined conditions. For USAFRICOM, evacuations for non-battle injury and poisoning were ...

Article
Jun 1, 2022

Ambulatory Visits, Active Component, U.S. Armed Forces, 2021

In 2021, the overall numbers and rates of active component service member ambulatory care visits were the highest of any of the last 10 years. Most categories of illness and injury showed modest increases in numbers and rates. The proportions of ambulatory care visits that were accomplished via telehealth encounters fell to under 15% in 2021, compared ...

Article
May 1, 2022

The Association Between Two Bogus Items, Demographics, and Military Characteristics in a 2019 Cross-sectional Survey of U.S. Army Soldiers

NIANTIC, CT, UNITED STATES 06.16.2022 U.S. Army Staff Sgt. John Young, an information technology specialist assigned to Joint Forces Headquarters, Connecticut Army National Guard, works on a computer at Camp Nett, Niantic, Connecticut, June 16, 2022. Young provided threat intelligence to cyber analysts that were part of his "Blue Team" during Cyber Yankee, a cyber training exercise meant to simulate a real world environment to train mission essential tasks for cyber professionals. (U.S. Army photo by Sgt. Matthew Lucibello)

Data from surveys may be used to make public health decisions at both the installation and the Department of the Army level. This study demonstrates that a vast majority of soldiers were likely sufficiently engaged and answered both bogus items correctly. Future surveys should continue to investigate careless responding to ensure data quality in ...

Article
May 1, 2022

Update: Sexually Transmitted Infections, Active Component, U.S. Armed Forces, 2013–2021

This illustration depicts a 3D computer-generated image of a number of drug-resistant Neisseria gonorrhoeae bacteria. CDC/James Archer

This report summarizes incidence rates of the 5 most common sexually transmitted infections (STIs) among active component service members of the U.S. Armed Forces during 2013–2021. In general, compared to their respective counterparts, younger service members, non-Hispanic Black service members, those who were single and other/unknown marital status, ...

Article
Mar 1, 2022

Brief report: Using syndromic surveillance to monitor MIS-C associated with COVID-19 in Military Health System beneficiaries

Air Force 1st Lt. Anthony Albina, a critical care nurse assigned to Joint Base Andrews, Md., checks a patient’s breathing and heart rate during an intubation procedure while supporting COVID-19 response operations in Cleveland, Jan. 20, 2022.

SARS CoV-2 and the illness it causes, COVID-19, have exacted a heavy toll on the global community. Most of the identified disease has been in the elderly and adults. The goal of this analysis was to ascertain if user-built ESSENCE queries applied to records of outpatient MHS health care encounters are capable of detecting MIS-C cases that have not ...

Article
Mar 1, 2022

Surveillance Snapshot: Medical Separation from Service Among Incident Cases of Osteoarthritis and Spondylosis, Active Component, U.S. Armed Forces, 2016–2020

Marines hike to the next training location during Exercise Baccarat in Aveyron, Occitanie, France, Oct.16, 2021. Exercise Baccarat is a three-week joint exercise with Marines and the French Foreign Legion that challenges forces with physical and tactical training. Photo By: Marine Corps Lance Cpl. Jennifer Reyes

Osteoarthritis (OA) is the most common adult joint disease and predominantly involves the weight-bearing joints. This condition, including spondylosis (OA of the spine), results in significant disability and resource utilization and is a leading cause of medical separation from military service.

Article
Mar 1, 2022

Obesity prevalence among active component service members prior to and during the COVID-19 pandemic, January 2018–July 2021

Maintaining a healthy weight is important for military members to stay fit to fight. The body mass index is a tool that can be used to determine if an individual is at an appropriate weight for their height. A person’s index is determined by their weight in kilograms divided by the square of height in meters. (U.S. Air Force photo illustration by Airman 1st Class Destinee Sweeney)

This study examined monthly prevalence of obesity and exercise in active component U.S. military members prior to and during the COVID-19 pandemic. These results suggest that the COVID-19 pandemic had a small effect on the trend of obesity in the active component U.S. military and that obesity prevalence continues to increase.

Article
Mar 1, 2022

Brief Report: Refractive Surgery Trends at Tri-Service Refractive Surgery Centers and the Impact of the COVID-19 Pandemic, Fiscal Years 2000–2020

Cadet Saverio Macrina, U.S. Military Academy West Point, receives corneal cross-linking procedure at Fort Belvoir Community Hospital, Va., Nov. 21, 2016. (DoD photo by Reese Brown)

Since the official introduction of laser refractive surgery into clinical practice throughout the Military Health System (MHS) in fiscal year 2000, these techniques have been heavily implemented in the tri-service community to better equip and improve the readiness of the U.S. military force.

Skip subpage navigation
Refine your search
Last Updated: May 07, 2024
Follow us on Instagram Follow us on LinkedIn Follow us on Facebook Follow us on X Follow us on YouTube Sign up on GovDelivery