Today the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota and NEJM Evidence launched their new Public Health Alerts initiative with reports on potential local transmission of clade 1b mpox virus (MPXV) in California and on influenza viruses circulating during the 2024-25 flu season.
Public Health Alerts is designed to deliver information and early warnings about emerging health threats, enabling swift, informed responses across the United States and globally.
Local clade 1b mpox in California
The first report, written by scientists with the California Department of Public Health and their local and national collaborators, details three men whose symptoms began in mid to late September 2025 and whose infections were confirmed as caused by clade 1b MPXV in October. One man was “severely immunocompromised,” but all survived.
None of the three reported sexual contact within the 21-day maximum incubation period for mpox, but each reported other intimate or skin-to-skin contact. None of the men had recently traveled outside the country.
Contract tracing revealed no further transmission, and interviews with public health officials found no epidemiologic links among the three men.
The authors conclude, “This report represents evidence of community transmission of clade Ib MPXV in the Americas and suggests the virus may be circulating undetected among gay, bisexual, and other men who have sex with men and their social networks.”
H3N2 strain was predominant last flu season
The second report describes surveillance findings from the Department of Defense network, which includes more than 115 sentinel and lab partners.
Investigators analyzed 1,341 viruses from August 2024 to February 2025. They found that 55% were the H3N2 strain of influenza A, 40% were influenza A H1N1, 6.2% were influenza B (Victoria lineage), and 2.7% were undefined. They said the findings were consistent with data presented this year at the World Health Organization’s Northern Hemisphere (NH) vaccine selection meeting.
The authors conclude, “The DoD data on circulating influenza virus characteristics and [vaccine effectiveness] support the World Health Organization NH 2025–2026 influenza vaccine strain selections, which were to continue the 2024–2025 component of A(H1N1) pdm09 and B/Victoria while updating the A(H3N2) strain components.”
Filling a gap
The new collaboration between NEJM Evidence and CIDRAPfills a gap in reliable data, offering expert-reviewed reports that translate frontline observations into actionable public health evidence. An NEJM Evidence editorial today explains the initiative further.
“Access to emerging public health data saves lives,” said infectious disease doctor Eric J. Rubin, MD, Editor-in-Chief of the New England Journal of Medicine and NEJM Group, publisher of NEJM Evidence, in a news release. “By providing this new, rigorous pathway for public health information, NEJM Group is delivering on its commitment to equip physicians with reliable information to support evidence-based care.”
“Rapid, credible communication has always been essential to an effective public health response,” added CIDRAP Director Michael Osterholm, PhD, MPH. “With this new collaboration, we hope to restore and strengthen that early-warning function, providing timely, evidence-based alerts that can help local and state health leaders act quickly to protect the health of people in their communities.”
