In this comprehensive article, we delve into the latest information regarding the state of COVID-19, influenza (flu), and Respiratory Syncytial Virus (RSV) in the healthcare system.
This analysis is based on data from week 35 of the year 2023, offering valuable insights into the ongoing situation in Atención Primaria (primary care) and hospitals. Additionally, we explore the prevalence of specific variants and provide recommendations for enhanced monitoring.
Acute Respiratory Infection in Primary Care (ARIs) – Primary Care
The data from week 35/2023 reveals that the global rate of Acute Respiratory Infections (IRAs) in primary care stands at 338.2 cases per 100,000 inhabitants.
Of particular concern is the positivity rate for SARS-CoV-2, which currently stands at 40.6%, indicating a substantial presence of the virus. In contrast, the positivity rate for influenza (flu) remains relatively low at 0.6%.
Infección Respiratoria Aguda Grave en Hospitales (IRAG) – Hospitals
In the hospital setting, the rate of Severe Acute Respiratory Infections (IRAG) for week 35/2023 is 8.6 cases per 100,000 inhabitants. This rate has been on the rise since week 28/2023 when it was 7.5 cases per 100,000 inhabitants. The positivity rate for SARS-CoV-2 in hospitals is 35%, indicating a considerable presence of COVID-19 patients. Meanwhile, the positivity rate for the flu is 0.9%, suggesting a lower impact of influenza in hospitals.
In primary care, the flu rate for week 35/2023 is 3 cases per 100,000 inhabitants, maintaining baseline levels since week 20/2023. A similar pattern is observed in hospital admissions since week 22/2023. During the current flu season, the influenza type A virus has been identified in the majority of cases (84.3%), with subtype A(H3) accounting for 63% and A(H1)pdm09 for 37% of the subtyped cases.
COVID-19 continues to pose a significant challenge in primary care, with a rate of 137.3 cases per 100,000 inhabitants in week 35/2023. This rate has steadily increased since week 26/2023 when it was 30 cases per 100,000 inhabitants.
Notably, the highest rates are observed in children under the age of 4, reaching 253.62 cases per 100,000 inhabitants.
In recent weeks, the predominant COVID-19 variants have been XBB.1.5 (25%) and XBB.1.5-like+F456L (25%).
Throughout the 2022-23 season, the most prevalent variants have been XBB.1.5 (33.1%), BQ.1 (31.5%), and BA.5 (8.3%).
The hospitalization rate for COVID-19 is 3 cases per 100,000 inhabitants, with a steady increase since week 26/2023 when it was 0.52 cases per 100,000 inhabitants. Among hospitalized patients, the highest rates are observed in individuals over the age of 79. In recent weeks, the dominant variants among hospitalized cases have been XBB.1.5 (29%), BA.2.75 (14%), and XBB.1.5-like+F456L (14%). Throughout the season, the prevalent variants have been XBB.1.5 (32%) and BQ.1 (29%).
Respiratory Syncytial Virus (VRS)
In contrast to the dynamic trends seen in COVID-19 and influenza, Respiratory Syncytial Virus (VRS) infection rates have remained at baseline levels for several weeks in both primary care and hospitals. The highest incidence rates were observed in children under the age of 5 during weeks 47/2022 (161 cases/100,000 inhabitants) and 48/2022 (9.2 cases/100,000 inhabitants) in primary care and hospitals, respectively.
Influenza Positivity Rates
One key highlight is that the positivity rate for influenza remains consistently at baseline levels throughout this period. Since the commencement of the influenza season, a total of 33,882 samples for Acute Respiratory Infections (IRAs) have been analyzed for influenza diagnosis. Among these samples, 5,911 detections of influenza viruses were recorded.
Breaking down these detections, 3,571 cases (60.8%) were attributed to influenza type A, with further subtyping revealing 2,054 cases as A(H3) and 983 cases as A(H1)pdm09, accounting for 68% and 32% of the subtyped cases, respectively. Additionally, 534 cases of influenza type A were not subtyped, constituting 9% of the detections. Alongside type A, 2,303 cases (39.2%) of influenza type B were identified, reaffirming the coexistence of both influenza types during the season.
It is noteworthy that the positivity rate for Respiratory Syncytial Virus (RSV) has remained at baseline levels, indicating a relatively stable situation regarding RSV in primary care.
Progressive Increase in COVID-19 Positivity
In stark contrast to the stable influenza and RSV trends, the positivity rate for SARS-CoV-2, the virus responsible for COVID-19, exhibited a distinct pattern. Initially, in week 10/2023, the positivity rate stood at 5%. However, from this point, it showed a progressive increase, reaching 24% by week 18/2023. Subsequently, there were fluctuations in the positivity rate until week 26/2023.
From week 26/2023 onwards, the positivity rate for SARS-CoV-2 began to rise once more, with fluctuations in the data.
By week 35/2023, it had reached a rate of 40%. This increase in COVID-19 positivity rates emphasizes the evolving nature of the pandemic and underscores the need for continued vigilance and public health measures.
In light of these findings, it is advisable to increase the sequencing of sentinel cases of Acute Respiratory Infections (IRAs) and Severe Acute Respiratory Infections (IRAG) that test positive for SARS-CoV-2. Enhanced sequencing efforts can improve the sensitivity in identifying circulating variants of the virus, aiding in the development of targeted strategies for containment and mitigation.
The data presented in this article highlights the persistent challenges posed by COVID-19 in primary care, with signs of stabilization in hospital settings. The presence of specific variants, such as XBB.1.5 and XBB.1.5-like+F456L, underscores the need for ongoing surveillance and public health measures. Additionally, the maintenance of baseline levels for influenza and RSV offers a glimpse of hope amid the continued pandemic response. Vigilance, data-driven decision-making, and the promotion of vaccination remain key components in our collective effort to combat respiratory infections and protect public health.
reference link : https://www.isciii.es/QueHacemos/Servicios/VigilanciaSaludPublicaRENAVE/EnfermedadesTransmisibles/Documents/GRIPE/Informes%20semanales/Temporada_2022-23/Informe%20semanal_SiVIRA_352023.pdf