Eurosurveillance - Volume 28, Issue 8, 23 February 2023

Sequencing of SARS-CoV-2 PCR-positive samples was introduced in Slovenia in January 2021. Our surveillance programme comprised three complementary schemes: (A) non-targeted sequencing of at least 10% of samples, (B) sequencing of samples positive after PCR screening for variants of concern (VOC) and (C) sequencing as per epidemiological indication.

We present the analysis of cumulative data of the non-targeted surveillance of SARS-CoV-2 and variant-dependent growth kinetics for the five most common variants in Slovenia for the first 9 months of 2021.

SARS-CoV-2 PCR-positive samples, from January to September 2021, were selected for sequencing according to the national surveillance plan. Growth kinetics studies were done on Vero E6 cells.

Altogether 15,175 genomes were sequenced and 64 variants were detected, of which three successively prevailed. Variant B.1.258.17 was detected in ca 80% of samples in January and was replaced, within 9 weeks, by the Alpha variant. The number of cases decreased substantially during the summer of 2021. However, the introduction of the Delta variant caused a fourth wave and completely outcompeted other variants. Other VOC were only detected in small numbers. Infection of Vero E6 cells showed higher replication rates for the variants Alpha and Delta, compared with B.1.258.17, B.1.258, and B.1.1.70, which dominated in Slovenia before the introduction of the Alpha and Delta variants.

Information on SARS-CoV-2 variant diversity provided context to the epidemiological data of PCR-positive cases, contributed to control of the initial spread of known VOC and influenced epidemiological measures.

Herpes zoster (HZ) affects 1 in 3 persons in their lifetime, and the risk of HZ increases with increasing age and the presence of immunocompromising conditions. In Spain, vaccination guidelines were recently updated to include the recommendation of the new recombinant zoster vaccine (RZV) for certain risk groups.

To describe the epidemiology of HZ-related hospitalisations in Spain in order to prioritise vaccination recommendations and define a baseline to monitor the effectiveness of vaccination policies.

Retrospective study using the National Health System’s Hospital Discharge Records Database, including all HZ-related hospitalisations from 1998 to 2018.

The 65,401 HZ-related hospitalisations, corresponded to an annual mean hospitalisation rate of 6.75 per 100,000 population. There was an increasing trend of HZ hospitalisations over the study period. This rate was higher in males and older age groups, particularly over 65 years. Comorbidities with higher risk of readmission were leukaemia/lymphoma (RR 2.4; 95% CI: 2.3–2.6) and solid malignant neoplasm (RR 2.2; 95% CI: 2.1–2.4). Comorbidities associated with higher risk of mortality were leukaemia/lymphoma (RR 2.9; 95% CI: 2.7–3.2), solid malignant neoplasm (RR 2.9; 95% CI: 2.7–3.1) and HIV infection (RR 2.2; 95% CI: 1.8–2.7).

Of all patients hospitalised with HZ, those with greater risk of mortality or readmission belonged to the groups prioritised by the current vaccination recommendations of the Spanish Ministry of Health. Our study provided relevant information on clinical aspects of HZ and established the base for future assessments of vaccination policies.