Media briefing: Vaccine and Virus Trends Ahead of Winter

The Johns Hopkins Bloomberg School of Public Health hosted a media briefing on Dec. 16, 2025, to examine the latest trends in seasonal respiratory viruses as the U.S. enters the winter season, as well as overall vaccine rates and the risk that the U.S. will lose its measles elimination status.

With influenza cases rising, respiratory syncytial virus (RSV) activity at low levels, and continued monitoring of COVID-19 variants, speakers broke down what these patterns mean for transmission risks, health systems, and prevention efforts.

Topics discussed:

Current U.S. influenza activity, including circulation of H1N1, IBV, and the emerging H3N2 clade K strain.

Why RSV cases are unusually low this season and what that means for vulnerable populations.

COVID-19 trends heading into winter and how they may overlap with flu season.

Vaccination uptake patterns.

Rising measles cases and the risk of the U.S. losing its measles elimination status.

Key takeaways from the December 2025 Advisory Committee on Immunization Practices (ACIP) meeting and potential impacts on vaccine confidence.

Insights from:

William Moss, MD, a professor in the departments of Epidemiology; International Health; and Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, and executive director at the Bloomberg School’s International Vaccine Access Center.

Andrew Pekosz, PhD, a professor and vice chair of the W. Harry Feinstone Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, and co-director of the Johns Hopkins Center of Excellence in Influenza Research and Response.

Resources:

2025–2026 Flu Season, CDC
https://www.cdc.gov/flu/season/2025-2...

How Cuts to mRNA Vaccine Development Will Set the U.S. Back, Johns Hopkins Bloomberg School of Public Health
https://publichealth.jhu.edu/2025/ris...

U.S. Measles Cases Hit Highest Level Since Declared Eliminated in 2000, Johns Hopkins Bloomberg School of Public Health
https://publichealth.jhu.edu/ivac/202...

U.S. Measles Tracker
https://publichealth.jhu.edu/ivac/res...

Across the U.S., Childhood Vaccination Rates Continue to Decline
https://publichealth.jhu.edu/ivac/202...

Vaccines, Johns Hopkins Bloomberg School of Public Health
https://publichealth.jhu.edu/topics/v...

Vaccines Do More Than Prevent Disease, Johns Hopkins Bloomberg School of Public Health
https://publichealth.jhu.edu/2025/the...

Why Experts Have Concluded That Vaccines Do Not Cause Autism, Johns Hopkins Bloomberg School of Public Health
https://publichealth.jhu.edu/2025/vac...

Timestamps:

0:00 Introduction
01:50 Current respiratory viruses
03:55 Status of measles in U.S.
08:18 Checking measles antibodies
10:00 Vaccine uptake trends
11:42 Flu strains this year
13:02 Measles elimination status
18:05 Changes in CDC reporting of measles
19:45 Is it too late for flu shot
21:40 Clade k flu strain severity
24:08 Are there concerns about HHS messaging
25:30 CDC not holding briefings on measles
27:50 Where is clade K strain most prevalent
28:50 ACIP statements
30:20 Staying safe with holiday travel and gatherings
31:40 Resurgence of vaccine-preventable diseases


https://publichealth.jhu.edu
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