Key Points or Updates:

• Seasonal influenza activity remains elevated nationally and in New Jersey.

• The percentage of specimens testing positive, outpatient and emergency department visits, and admissions due to influenza are all higher than previous weeks and those reported last season.

• The most frequently reported influenza viruses so far this season have been Influenza A and among those subtyped Influenza A(H3N2) is the most common.

• A new influenza A(H3N2) virus subclade J.2.4.1, renamed “H3N2 subclade K,” was identified by CDC in August 2025. Although this has been characterized as an antigenic drift in comparison to the A(H3N2) component of the 2025-26 seasonal influenza vaccine, it is too early to predict vaccine effectiveness for the season. 

• Influenza vaccination continues to be recommended for the 2025-26 influenza season.

• At this time there is also no indication that these subclade K influenza viruses are resistant to available influenza antiviral medications.  

• In New Jersey, influenza activity continues to be systematically captured as part of ongoing respiratory pathogen surveillance and is reported weekly through the Respiratory Report and Respiratory Illness Dashboard.

Action Items:

• Healthcare providers should continue to recommend seasonal influenza vaccination for all eligible persons 6 months and older and initiate prompt treatment with antivirals for those hospitalized with suspected or confirmed influenza or those at a higher risk for influenza-associated complications.

• Healthcare facilities should continue to review and implement measures and stay up to date with public health recommendations to limit transmission within the healthcare setting. 

• Schools and Early Care and Education programs should encourage students, parents, and staff to get vaccinated and take everyday preventive actions to prevent illness. 

For additional information and recommendations, see the attachment. Please contact the Communicable Disease Service, Influenza Surveillance Unit at cdsfluteam@doh.nj.gov with any questions regarding this message.