Summary

1. Epidemiological Context

• RSV and Influenza Trends:
  Iceland is experiencing a notable surge in RSV infections, with rates exceeding those seen last winter. Most countries reporting to ECDC have observed sharp increases in both influenza and RSV activity, with co-circulation of influenza A(H1N1)pdm09, A(H3N2), and B viruses.

• Healthcare Impact:
  The concurrent circulation of influenza and RSV, against a backdrop of low SARS-CoV-2 transmission, poses significant risks to healthcare systems. Hospitalizations are affecting all age groups, with young children (due to RSV) and older adults being particularly vulnerable. Iceland's Landspítali Hospital has already experienced a notable burden due to RSV.

• Seasonal Risks:
  The festive season, with increased social gatherings, travel, and shopping, is likely to exacerbate respiratory virus transmission.

2. Recommendations

• Preparedness:
  We should anticipate further increases in influenza and RSV activity in the coming weeks and strengthen infection prevention and control measures in healthcare and long-term care facilities.

• Vaccination:
  Immunization remains the most effective method for preventing severe respiratory illness.

  • Updated COVID-19 booster vaccines for winter 2024/2025 offer enhanced protection against severe outcomes from circulating SARS-CoV-2 variants.

  • Individuals eligible for influenza or COVID-19 vaccination are encouraged to receive their vaccines promptly to have the best chance of being protected.

  • While RSV immunoprophylaxis for infants and vaccinations for adults are not yet part of Iceland's general immunization program, they are under consideration.

• Antiviral Treatments:
  Early administration of antivirals for influenza and COVID-19, as well as monoclonal antibodies for SARS-CoV-2, can help prevent severe disease in high-risk groups.

• Surveillance of Unusual Events:
  Clusters of respiratory infections, such as adenovirus or Mycoplasma pneumoniae, not routinely monitored, may add pressure on healthcare systems.

Epidemiological Trends in the EU/EEA

a. Respiratory Virus Activity
Weekly updates on respiratory virus trends are available on Iceland's Directorate of Health website and from ECDC.

• Recent data indicate a rapid increase in community transmission of influenza and RSV across most reporting countries in Europe.

• Seasonal patterns for influenza and RSV in Europe appear to be returning to pre-COVID-19 norms.

• In Iceland, influenza trends are similar to last year, though RSV rates are rising more sharply (Graph).

• SARS-CoV-2 activity remains stable at low levels, but its seasonal behavior remains unpredictable.

Graph. RSV infections in Iceland, winter 2023-2024 and 2024-2025 (as of week 50).

b. Severe Disease

• In Europe hospitalizations for influenza and RSV are rising, with older adults and young children most affected.

• RSV-related hospital admissions are predominantly seen in children aged 0–4 years, particularly infants, who account for the majority of severe cases. At Landspitali 30 individuals were admitted with RSV in week 50, 2024, thereof 11 infants.

• COVID-19 hospitalizations continue to predominantly affect individuals aged 65 and older.

c. Influenza

• Influenza subtypes A(H1N1)pdm09, A(H3N2), and B are co-circulating in Europe.

• It is too early to predict the dominant strains for the latter part of the season.

d. RSV

• RSV is not regularly typed in the laboratories but available data in Europe suggest equal circulation of RSV-A and RSV-B.

• Immunization products, including vaccines for older adults and monoclonal antibodies for infants, have demonstrated safety and efficacy in reducing RSV-related hospitalizations. While RSV immunoprophylaxis are not yet part of Iceland's general immunization program, they are under consideration.

e. COVID-19/SARS-CoV-2

• Variant Classification: KP.3 was dominant at the most recent peak of SARS-CoV-2 activity in summer 2024. XEC, a recombinant variant, has now emerged as the dominant strain in the EU/EEA. However, no evidence suggests it causes more severe disease.

• Updated COVID-19 vaccines are expected to offer improved protection for high-risk groups this winter, including against the most recent variants.

Immunization and Antiviral Use

a. Influenza and SARS-CoV-2

• Vaccination campaigns against influenza and COVID-19 are ongoing across the EU/EEA.

• Vaccination remains the single most effective measure for preventing infection and the development of severe disease among the elderly and persons with underlying medical conditions.

• People eligible for vaccination against COVID-19 or influenza, who are at higher risk of severe disease and who have not yet been vaccinated are strongly encouraged to do so.

• Healthcare workers are also encouraged to get vaccinated against influenza and COVID-19 to protect themselves and to reduce the risk of infecting vulnerable groups.

• Clinicians are reminded that, when indicated, the early use of antivirals against influenza and COVID-19 may prevent progression to severe disease in vulnerable groups.

b. RSV

• Certain high-risk infants in Iceland can access monthly palivizumab injections at hospital during the RSV season. Broader immunization measures for RSV for all infants and vaccination for adults are under consideration as part of the general immunization schedule.

Infection Prevention and Control

• The festive season amplifies the risk of respiratory virus transmission. Healthcare systems should prepare for potential surges with increasing strain on ICU and emergency department capacity.

• Infection prevention measures, including staff vaccination and adherence to hygiene protocols, are essential to mitigate outbreaks in healthcare and long-term care settings.

• In addition to influenza, RSV and COVID-19, unusual events or clusters of respiratory infections, not monitored by routine surveillance, can place additional strain on healthcare systems.

• Those that are ill are reminded of respiratory etiquette and good hand hygiene and to stay at home while they have symptoms.

• Vaccinations are being offered to vulnerable groups. People with high risk for severe disease should also consider using a face mask when in crowded public spaces.

The Chief Epidemiologist