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.

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

Image of 48088663. This report provides an overview of the 2023-2024 mid-season analysis of influenza vaccine effectiveness against medically-attended ambulatory influenza infections.

This Surveillance Snapshot provides an overview of the 2023-2024 mid-season analysis of influenza VE against medically-attended ambulatory influenza infections among active component service members. Data from the Defense Medical Surveillance System, the NHRC’s respiratory surveillance program, and standardized laboratory data provided by the Defense Centers for Public Health–Portsmouth were used for this analysis.1,2 A case test-negative study design was implemented among the population of ACSMs from all services who were tested for influenza between December 1, 2023 and February 23, 2024—the period of peak influenza activity for the season. 

Cases were defined as individuals with a positive influenza result from a rapid antigen, reverse transcription polymerase chain reaction or culture influenza assay. Test-negative controls were individuals with a negative influenza result from a RT-PCR or culture influenza assay. Crude odds ratios were calculated and multivariate logistic regression was used to calculate adjusted ORs (adjusted for sex, age category, prior vaccination [any influenza vaccine in previous 5 years], and month of diagnosis) and 95% confidence intervals. VE estimates were defined as (1 - OR) x 100. 

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

There were 3,540 cases—2,794 A (any subtype), 246 A(H3N2), 119 A(H1N1)pdm09, 751 B (any type)—and 16,411 TNCs. TNCs were more likely vaccinated (85.4%) than cases (82.5%). VE varied by influenza type (Table). Statistically significant VE was found against any influenza case with an adjusted VE of 21% (95% CI: 13, 29) and influenza A (any subtype) with an adjusted VE of 26% (95% CI: 18, 34). The VE point estimate against influenza A(H1N1)pdm09 and A(H3N2) showed effectiveness, but did not reach statistical significance (23% [95% CI: -23, 51] and 28% [95% CI: -1, 49], respectively). This mid-season assessment did not find the vaccine to be effective against influenza B ambulatory infections (-5% [95% CI: -30, 15]). 

The results of this analysis show low protection of the 2023-2024 seasonal influenza vaccines against medically-attended influenza A infections that resulted in ambulatory care visits among ACSMs. As these estimates were obtained during the middle of the influenza season, VE estimates and CIs may change when data from the full season are available and sample sizes increase. 

References

  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 
  2. https://www.med.navy.mil/Naval-Medical-Research-Command/R-D-Commands/Naval-Health-Research-Center/Core-Research/Operational-Infectious Diseases/respiratory-surveillance-2023-2024

You also may be interested in...

Article
Mar 1, 2024

Coverage of HIV Pre-Exposure Prophylaxis Within the Active Duty U.S. Military, 2023

This study provides the first estimate of HIV pre-exposure prophylaxis coverage in the U.S. military, defined as the proportion of the persons taking HIV PrEP out of the estimated number of persons who had indications for it, that is also comparable to U.S. civilian estimates. The population with indications for HIV PrEP was obtained from the ...

Article
Mar 1, 2024

Mid-Season Influenza Vaccine Effectiveness Estimates Among DOD Populations: A Composite of Data Presented at VRBPAC—the Vaccines and Related Biological Products Advisory Committee—2024 Meeting on Influenza Vaccine Strain Selection for the 2024-2025 Influenza Season

This is an introduction to a composite of three Surveillance Snapshots of Department of Defense data on mid-season influenza vaccine effectiveness that were presented at the 2024 VRBPAC meeting.

Article
Mar 1, 2024

Tobacco and Nicotine Use Among Active Component U.S. Military Service Members: A Comparison of 2018 Estimates from the Health Related Behaviors Survey and the Periodic Health Assessment

This study compared estimates of the prevalence of and risk factors for tobacco and nicotine use obtained from the 2018 Health Related Behaviors Survey and Periodic Health Assessment survey. The HRBS and the PHA are important Department of Defense sources of data on health behavior collected from U.S. military service members.

Report
Mar 1, 2024

MSMR Vol. 31 No. 3 - March 2024

.PDF | 1.34 MB

The March 2024 MSMR features a comparison of 2018 estimates from the HRBS and the PHA on tobacco and nicotine use among the U.S. military active component; followed by a report on coverage of HIV PrEP among active duty service members in 2023; supplemented by a Surveillance Snapshot of HIV PrEP prescriptions in 2023 in the active component; then a ...

Article
Jan 1, 2024

Ivermectin Prescription Fill Rates Among U.S. Military Members During the Coronavirus Disease 2019 (COVID-19) Pandemic

This report describes ivermectin prescription fill rates among U.S. active component service members over time during the early phases of the COVID-19 pandemic. Ivermectin prescription fill rates increased among active component service members early in the COVID-19 pandemic when misinformation about the effectiveness of ivermectin for prevention and ...

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