PAHO: Strengthened Vaccination & Surveillance Needed for H3N2 in Americas

PAHO Alerts South American Countries to Emerging Influenza Strain and Reinforces Preparedness for 2025-2026 Season

The Pan American health Organization (PAHO) has issued an alert to its member States regarding the increasing prevalence of an influenza subclade, K, in south America, based on data reported to the global Initiative on Sharing All Influenza Data (GISAID). While this genetic evolution is considered a natural part of seasonal influenza virus variation, PAHO is urging countries to strengthen surveillance, vaccination efforts, and preparedness for potential increased activity in the upcoming 2025-2026 influenza season. Preliminary data from Europe suggests current influenza vaccines continue to offer comparable protection against severe illness, including hospitalization, as in previous years.

Emerging Influenza Subclade K in South America

Recent genomic surveillance reveals a growing presence of influenza subclade K in South America. PAHO emphasizes that this is a natural evolutionary process for influenza viruses,meaning the virus is adapting and changing as it circulates within populations.https://www.paho.org/en

Vaccine effectiveness and Current Data

Although comprehensive data on vaccine effectiveness for the current season is still being collected, initial findings from Europe are encouraging. These findings indicate that existing influenza vaccines continue to provide a level of protection against severe disease, including hospitalization, similar to that observed in previous years.This underscores the continued importance of vaccination, notably for vulnerable populations.

PAHO Recommendations for Member States

PAHO has issued a series of recommendations to help Member States proactively address the evolving influenza situation:

* Strengthen Surveillance: Maintain and enhance epidemiological, virological, and genomic surveillance systems to track the spread and evolution of influenza viruses, as well as other respiratory pathogens like RSV and SARS-CoV-2.
* Increase Vaccination Coverage: Prioritize and expand influenza vaccination coverage,especially among high-risk groups.
* Timely Treatment: Ensure prompt access to antiviral treatments for individuals at higher risk of complications.
* Health Service Preparedness: Reinforce the capacity of health services to manage a potential early or more intense influenza season during the 2025-2026 season in the Northern Hemisphere.
* Data Reporting & Sequencing: Continue regular reporting of epidemiological data and submit samples for genomic sequencing to identify emerging variants.
* Investigate Unusual Events: Immediately investigate and report any unusual respiratory events, adhering to the guidelines of the International Health Regulations.
* Promote Preventative Measures: Reinforce public health messaging on personal preventative measures like handwashing, covering coughs and sneezes, and staying home when sick.

High-Risk Groups and Vaccination

PAHO specifically recommends prioritizing influenza vaccination for the following groups:

* Older Adults: Individuals aged 65 years and older are at increased risk of severe complications from influenza.
* Individuals with Chronic Conditions: People with underlying medical conditions, such as asthma, diabetes, heart disease, and lung disease, are more vulnerable to severe illness.
* Pregnant women: Influenza infection during pregnancy can pose risks to both the mother and the developing fetus.
* Other High-Risk Groups: Healthcare workers, young children (especially those under 5 years old), and individuals with weakened immune systems should also be prioritized for vaccination.Vaccinating these populations helps reduce the burden on healthcare systems.

Ongoing Alert and Continued Vigilance

The recommendations outlined in PAHO’s December 4 Epidemiological Alert remain in effect. This alert emphasizes the importance of integrated surveillance for influenza, respiratory syncytial virus (RSV), and SARS-CoV-2, alongside continuous data reporting and genomic sequencing. https://www.paho.org/en/news/pan-american-health-organization-paho-issues-alert-increase-respiratory-diseases

Key Takeaways:

* An emerging influenza subclade (K) is circulating in South America.
* Current vaccines appear to remain effective against severe illness.
* PAHO urges strengthened surveillance, vaccination, and preparedness.
* High-risk groups should be prioritized for vaccination.
* Personal preventative measures are crucial for limiting transmission.

PAHO will continue to monitor the situation closely and provide updated guidance to Member States as new information becomes available. Proactive measures and continued vigilance are essential to mitigate the impact of influenza and protect public health in the Americas.