Eurosurveillance - Volume 29, Issue 39, 26 September 2024

Influenza viruses can cause large seasonal epidemics with high healthcare impact and severity as they continually change their virological properties such as genetic makeup over time.

We aimed to monitor the characteristics of circulating influenza viruses over the 2022/23 influenza season in the EU/EEA countries. In addition, we wanted to compare how closely the circulating viruses resemble the viral components selected for seasonal influenza vaccines, and whether the circulating viruses had acquired resistance to commonly used antiviral drugs.

We performed a descriptive analysis of the influenza virus detections and characterisations reported by National Influenza Centres (NIC) from the 30 EU/EEA countries from week 40/2022 to week 39/2023 to The European Surveillance System (TESSy) as part of the Global Influenza Surveillance and Response System (GISRS).

In the EU/EEA countries, the 2022/23 influenza season was characterised by co-circulation of A(H1N1)pdm09, A(H3N2) and B/Victoria-lineage viruses. The genetic evolution of these viruses continued and clade 6B.1A.5a.2a of A(H1N1)pdm09, 3C.2a1b.2a.2b of A(H3N2) and V1A.3a.2 of B/Victoria viruses dominated. Influenza B/Yamagata-lineage viruses were not reported.

The World Health Organization (WHO) vaccine composition recommendation for the northern hemisphere 2023/24 season reflects the European virus evolution, with a change of the A(H1N1)pdm09 component, while keeping the A(H3N2) and B/Victoria-lineage components unchanged.

Carriage of multidrug-resistant organisms (MDROs) in humans constitutes an important public health concern. Cross-transmission of bacteria between animals and humans has been demonstrated before.

Our aim was to quantify the risk factor ‘pet ownership’ for MDRO colonisation in hospital patients.

We performed a matched case–control study from 2019 to 2022 in Berlin, Germany and compared MDRO-positive and MDRO-negative patients in terms of contact with pets and other risk factors for MDRO acquisition. Patients completed a questionnaire-based interview and provided nasal and rectal swabs. Pet owners provided swab samples from the throat and stool of their pets (dogs and cats). Phenotypically matching samples of owners and pets were analysed via whole genome sequencing.

The analyses included 2,891 patients. Reported pet ownership was 17.7% in MDRO-positives (154/871) and 23.4% in MDRO-negatives (472/2,020). Among 397 owner–pet pairs, we identified one pair sharing genotypically indistinguishable pathogens (0.3%). A risk factor analysis of pet ownership was performed for carriers of meticillin-resistant Staphylococcus aureus (MRSA) (OR = 0.662; 95% CI: 0.343–1.277), vancomycin-resistant enterococci (VRE) (OR = 0.764; 95% CI: 0.522–1.118) and multidrug-resistant Gram-negative bacteria (MDR-GNB) (OR = 0.819; 95% CI: 0.620–1.082). Colonisation with MDRO was rare in pets, and dogs were more often colonised than cats (MRSA: 0% vs 0%, VRE: 1.5% vs 1.0%, MDR-GNB: 17.2% vs 3.6%).

Transmission of MDROs between humans and pets is possible though rare. In an urban living space, neither cat nor dog ownership appears as a relevant risk factor for MDRO carriage in hospital patients.

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infections and hospitalisations in infants (age < 1 year) and young children. Little is known on RSV epidemiology and related inpatient healthcare resource use (HCRU) in Switzerland.

To explore RSV-related hospitalisations, inpatient HCRU and medical costs in all age groups, and risk factors for infant hospitalisations in Switzerland.

We used national hospital registry data from 2003 to 2021 identifying RSV cases with ICD-10-GM codes, and described demographic characteristics, HCRU and associated medical costs of RSV inpatients. The effect of risk factors on infant hospitalisation was estimated with logistic regression.

We observed a general increase and biannual pattern in RSV hospitalisations between 2003/04 and 2018/19, with 3,575 hospitalisations in 2018/19 and 2,487 in 2019/20 before numbers declined in 2020/21 (n = 902). Around two thirds of all hospitalisations occurred in infants. Mean (median) age was 118 (85) days in hospitalised infants and 74 (77) years in hospitalised adult patients (> 18 years); 7.2% of cases required intensive care unit stay. Mean inpatient medical costs were estimated at EUR 8,046. Most (90.8%) hospitalised infants with RSV were born after 35 weeks of gestation without bronchopulmonary dysplasia or congenital heart disease. Low birth weight, gestational age and congenital disorders were associated with a higher risk for hospitalisation.

RSV leads to a substantial number of hospitalisations and peaks in hospital capacity utilisation. Measures to protect all infants from an RSV hospitalisation are essential in addressing this public health challenge.

Since February 2022, the start of the full-scale war in Ukraine, millions of women and children have fled the country. Vaccination of refugee children is important to protect this vulnerable population from disease.

We investigate the determinants of vaccination intention in refugee mothers from Ukraine residing in Poland and test the effect of three message frames.

Participants were randomised into either a control group or one of three intervention groups encouraging vaccination using a specific frame: (i) trust in the Polish health system, (ii) ease of access to vaccination or (iii) risk aversion. Primary outcomes were intention to vaccinate a child in Poland and clicking on a vaccination scheduling link.

The study was completed by 1,910 Ukrainian refugee mothers. Compared with the control group, the risk aversion message significantly increased vaccination intention (adjusted odds ratio (AOR): 2.35, 95% confidence interval (CI): 1.25–4.42) and clicking on the vaccine scheduling link (AOR: 1.53, 95% CI: 1.12–2.09). Messages around trust and ease of access did not have an effect. Important determinants of vaccination intention were perceived importance of vaccination (AOR: 1.12 95% CI: 1.01–1.25) and trusting vaccination information official health institutes (AOR: 1.40 95% CI: 1.06–1.83) and social media (AOR: 2.09 95% CI: 1.33–3.27).

Using a risk aversion frame highlighting the vulnerability to infection that refugees face resulted in increased vaccination intention and clicks on a vaccination scheduler. Health workers who interact with Ukrainian refugees could use this frame in their vaccination communication.