Weekly updates, Influenza Epidemiological Week 23 (16 June 2023)

North America: Influenza activity has remained at low levels. During the last 4 epidemiological weeks (EW), the predominant influenza viruses have been B/Victoria, with a lesser circulation of influenza A (mostly A(H1N1)pdm09). Respiratory syncytial virus (RSV) activity has remained low. The activity of SARS-CoV-2 has decreased, although it continues to circulate at moderate levels. Cases of influenza-like illness (ILI) and severe acute respiratory infection (SARI) have shown a decreasing trend, with the majority of these cases associated with SARS-CoV-2 and to a lesser extent influenza.

Caribbean: Influenza activity has shown a decreasing trend. During the last 4 epidemiological weeks, the predominant influenza viruses have been B/Victoria, with lesser circulation of influenza A (mainly A(H1N1)pdm09). RSV activity has remained low. SARSCoV-2 activity has increased in the last 4 weeks and is currently at intermediate levels of circulation. Cases of ILI have shown a slight increase due to positive SARS-CoV-2 cases. SARI cases remain low.

Central America: Influenza activity has shown a pronounced increase in the last 4 weeks with high levels of circulation. During the last 4 epidemiological weeks, the predominant influenza viruses have been influenza A, mainly A(H1N1)pdm09, with concurrent circulation of influenza A(H3N2) and influenza B/Victoria to a lesser extent. RSV activity has remained low. SARS-CoV-2 activity has remained low and has decreased in recent weeks. SARI and ILI activity have remained low, with the majority of cases associated with influenza.

Andean region: Influenza activity remains stable at low levels. During the last 4 weeks, the predominant influenza viruses have been influenza A, mostly A(H1N1)pdm09, with lesser circulation of influenza B/Victoria. RSV activity has shown a slight increase, remaining at moderate levels of circulation. SARS-CoV-2 has shown an increase, circulating at moderate levels. SARI activity is declining, with the majority of cases associated with influenza and RSV. ILI activity has shown a decreasing trend, with the majority of cases associated with influenza.

Brazil and Southern Cone: Influenza activity has decreased to moderate levels of circulation. During the last 4 EWs, the predominant influenza viruses have been mainly A(H1N1)pdm09, with simultaneous circulation of influenza B/Victoria virus. RSV activity has decreased in the last two EWs, reaching medium-low levels. SARS-CoV-2 activity has remained low. After reaching a peak, both SARI and ILI activity have decreased in the last 4 EWs, with the majority of cases testing positive for RSV and influenza. In Chile, extraordinary levels of ILI activity have been observed, with the majority of cases related to RSV and influenza, which has decreased in the last week. Moderate levels of SARI activity have also been detected in Chile, with RSV being the most common cause among positive cases, and this activity has also decreased in the last week. In Paraguay, a high level of SARI activity has been observed, with RSV being the main cause among positive cases, followed by influenza and to a lesser extent SARS-CoV-2. In Uruguay, an increase in SARI activity has been detected, reaching low-to-moderate levels, with the majority of cases associated with RSV, followed by influenza.