The European 2025/26 influenza season is dominated by the influenza A(H3N2) virus, with most sequenced viruses belonging to subclade K, genetically drifted from the vaccine virus, raising concerns around vaccine effectiveness (VE). Despite this, VE estimates from nine European studies (19 countries) indicate all-age influenza A VE of 25-45% for outpatient and hospital settings combined, similar to other seasons, with highest estimates among children (47-72%). Vaccination should be encouraged and complemented by other infection prevention and control measures.

BACKGROUND:Uptake of the measles-mumps-rubella vaccine in Wales is high. However, sporadic measles cases still occur and there are large mumps outbreaks every few years. In this study, the long-term vaccine effectiveness (VE) of vaccines containing measles and mumps is assessed. METHODS:A retrospective cohort of 822 116 individuals aged 1-30 years were followed up between 1 January 2007 and 31 December 2020. Welsh Demographic Service data were linked to vaccination status from the national vaccination register and primary care records. Outcomes were identified by linking to laboratory confirmations (measles and mumps) and notifications (mumps) data. Complications were sourced from hospital admissions and primary care data. Extended Cox regression was used to calculate hazard ratios. RESULTS:The adjusted VE (aVE) against confirmed measles after two doses remained high after 15 years 99.7% [95% confidence interval (CI) 99.2-99.9]. The aVE for confirmed mumps was lower, with decline over time: 93.6% (95% CI 90.2-95.8) in the first 5 years after vaccination with dose two and 49.9% (95% CI 34.4-61.8) after ≥15 years. A third dose of mumps vaccine temporarily increases protection (87.6%, 95% CI 71.7-94.6). The aVE estimates for mumps were lower when based on clinical suspicion. The VE was high against complications for both infections. CONCLUSION:The high, sustained VE for measles strengthens evidence that elimination remains possible and the high VE against mumps complications is encouraging. Evidence for the waning of mumps immunity may be important when deciding to implement a third dose in outbreak settings. With the increased use of data linkage, studies should be conducted to corroborate these findings.

Background:Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in older adults. In 2023, the RSVpreF vaccine was licenced and recommended for adults through the UK's national immunisation programmes. Real-world evidence on vaccine effectiveness (VE) across different populations and healthcare settings is limited. Methods:We conducted a retrospective, multi-nation, test-negative design analysis to evaluate RSVpreF VE against hospitalisation in adults aged 74-79 years across England, Wales, Scotland, and Northern Ireland during the 2024-25 RSV season. Laboratory testing, admission, and vaccination data were linked at the individual patient level. Eligible cases were hospitalised individuals with laboratory-confirmed RSV, and controls were RSV-negative hospitalised patients; SARS-CoV-2- and influenza-positive controls were excluded in the primary analysis. Nation-specific VE estimates were derived using multivariable logistic regression, adjusted for epidemiological week of specimen collection, and combined using fixed-effects meta-analysis with inverse-variance weighting. Sensitivity analyses included redefinition of controls and leave-one-nation-out analyses. Findings:A total of 11,117 adults were included (6528 in England, 942 in NI, 1462 in Scotland, 2185 in Wales). Overall, 3896 (35.0%) had received RSVpreF. Across nations, 826 RSV-positive cases were identified, of whom 726 (87.9%) were unvaccinated. Adjusted VE against RSV-related hospitalisation was 74% (95% confidence interval [CI] 68-80) in England, 77% (30-95) in NI, 81% (60-91) in Scotland, and 82% (43-94) in Wales. Pooled fixed-effects VE was 75% (69-80; I 2 = 0%). VE estimates from sensitivity analyses were robust to the inclusion of vaccine-preventable respiratory infection controls and adjustment for vaccination status. Leave-one-nation-out sensitivity analysis showed that excluding England increased pooled VE to 81% (66-89), whereas exclusion of NI, Scotland, or Wales had minimal impact (75%, 68-80 to 69-80). Interpretation:RSVpreF vaccination provides high real-world protection against RSV-related hospitalisation in adults across the UK. Funding:This study received no specific funding.

Microbiology reference laboratories perform a crucial role within public health systems. This role was especially evident during the COVID-19 pandemic. In this Viewpoint, we emphasise the importance of microbiology reference laboratories and highlight the types of digital data and expertise they provide, which benefit national and international public health. We also highlight the value of surveillance initiatives among collaborative international partners, who work together to share, analyse, and interpret data, and then disseminate their findings in a timely manner. Microbiology reference laboratories have substantial impact at regional, national, and international levels, and sustained support for these laboratories is essential for public health in both pandemic and non-pandemic times.

The 2024/25 influenza season in Europe is currently characterised by co-circulation of influenza A(H1N1)pdm09, A(H3N2) and B/Victoria viruses, with influenza A(H1N1)pdm09 predominating. Interim vaccine effectiveness (VE) estimates from eight European studies (17 countries) indicate an all-age influenza A VE of 32–53% in primary care and 33–56% in hospital settings, with some signals of lower VE by subtype and higher VE against influenza B (≥ 58% across settings). Where feasible, influenza vaccination should be encouraged and other prevention measures strengthened.

This study provides descriptive analysis of a COVID-19 outbreak of 323 cases in a Welsh hospital in early 2021, with a focus on respiratory failure (RF) as a severe outcome. Multivariate analysis demonstrated decreased odds of RF in healthcare acquired cases (aOR 0.40 (95%CI 0.24-0.65), p<0.001) and individuals with at least one dose of vaccine 14 days before first positive test (aOR 0.45 (95%CI 0.28-0.75), p=0.002). In healthcare acquired cases, vaccination significantly reduced the odds of RF (OR 0.47 (95%CI 0.22-0.00), p=0.037). This analysis highlights the importance of vaccination as a protective factor against severe respiratory outcomes.

Introduction:: Respiratory Syncytial Virus (RSV) is a single-stranded RNA virus and a major cause of hospitalisations in paediatric and geriatric populations. In the Northern Hemisphere, the RSV season is typically between October and March. Following the introduction of Non-pharmaceutical Interventions (NPIs), in response to the COVID-19 pandemic, disruptions in seasonality have been observed. Methods:: We used an age-structured, deterministic SE2I2R model with time-dependent contact rates to study RSV hospitalisations and seasonality in the context of specific NPIs in Wales. The transmission process was linked to a clinical events model, to allow comparison to paediatric admissions data from Public Health Wales. The model was calibrated using Welsh demographics, social contact surveys and a severity index of Welsh NPI impact. Results:: Admissions data revealed three out-of-season outbreaks (Autumn 2020, Autumn 2021 and Summer 2022). A surge of admissions in Winter 2022-23 and Winter 2023-24 were forecasted, with peak timings correctly predicted, despite a more protracted outbreak observed in the data. Approximately, 90% of RSV admissions in Wales from 2016-22 were in infants under 1 year old; with the greatest shift in admissions age-structure in 2-4 year olds (quintupling in 2021). The model predicted a rapid return to pre-pandemic patterns after disruptions. Discussion/Conclusions:: Out-of-season peaks chiefly coincided with NPI relaxation. The post-pandemic response of RSV, in terms of timings, magnitude and age-structure shift, were all broadly consistent with simple interruptions in population exposure during the pandemic and the build up of immune naïve cohorts. Our model forms the basis of medium-term projections for paediatric RSV admissions in Wales.

Comparisons of SARS-CoV-2 variants' severity in terms of outcomes such as hospitalisation are commonly reported. By contrast, despite the vital importance of understanding evolution of the SARS-CoV-2 symptom profile for public health surveillance, few comparative studies have investigated differences in variants' symptomatology. The aim of this comprehensive analysis was to investigate whether successive variants were indeed associated with distinct symptom patterns in a large Welsh sample covering a broad time period and multiple variant waves. Symptom and variant typing data were derived from contact tracing data and sequencing of positive SARS-CoV-2 PCR tests collected in Wales, respectively. Descriptive epidemiology and binary logistic regression modelling were then used to investigate differences in the symptom profile of N = 226 002 cases infected with Wild-Type, Alpha, Delta, or Omicron variants of SARS-CoV-2. The median number of symptoms and the proportion of cases reporting as symptomatic were lower for those infected with Omicron (BA.4) and Omicron (BA.5) compared to those infected with Wild-Type (B.1.612), Alpha (B.1.1.7), Delta (B.1.617.2 and descendent lineages, excluding AY.4.2), Delta (AY.4.2), Omicron (BA.1) and Omicron (BA.2). Indeed, the odds of being symptomatic when infected with the Omicron (BA.4) or Omicron (BA.5) variant were 83% and 84% lower, compared to those infected with Wild-Type. Anosmia in particular, was reported in non-Omicron variants at approximately three-to-five times the proportion of cases (range 20.23%-26.41%) compared to Omicron variants (range 4.18%-7.65%). Indeed, the odds of having anosmia when infected with an Omicron variant were 85%-91% lower than when infected with Wild-Type, versus 32%-43% lower for non-Omicron variants, relative to Wild-Type. We suggest, given these changes in symptomatology and the vast reduction in testing and sequencing, symptom surveillance should continue, to approximate burden of infection and facilitate rapid updating of clinical case definitions following any further evolution in the symptom profile. While disentangling the contribution of genomic, immunological and sampling changes to our findings remains challenging, symptom surveillance could also potentially aid emerging variant detection when used in combination with other surveillance approaches.

The use of digital or electronic processes for gathering consent to immunisation for school-age vaccinations (“e-consent”) has the potential to improve the efficiency of the process. However, little is known currently about the effectiveness of e-consenting or implications on vaccination uptake and equity. MEDLINE, Embase, Cochrane Library, Scopus, PsycINFO, and Google Scholar were systematically searched for relevant publications from January 2000 until November 2024. Studies included in this review reported impact data on the use of digital or electronic processes as a means of obtaining informed consent for school-aged vaccinations. The quality of research included in the rapid review was assessed using the JBI critical appraisal tool for assessment of risk of bias for randomised controlled trials, the JBI checklist for quasi-experimental studies, and the mixed methods appraisal tool (MMAT). A narrative synthesis approach was used to analyse data and present findings. Four studies met the criteria for inclusion in the review. Included studies were conducted in the UK (n = 2) and USA (n = 2). Overall, the review findings appeared to suggest a preference by parents of school children for e-consent systems. Some parents found e-consent forms easy to use, however some others found the transition from traditional paper consent to e-consent difficult to adapt to. The use of e-consent did not appear to improve the timeliness of consenting or vaccination uptake. Language barriers, practical issues with transitioning to the new e-consent system, and concerns over lack of trust in electronic data, were among the reasons given for lack of engagement with the system. There is currently growing interest on the use of e-consent as a means of obtaining informed consent for school-aged vaccinations. However, there is a paucity of high-quality evidence on the benefits and limitations of e-consent. None of the four studies included in this review identified that use of e-consent led to improved uptake, and none evaluated the impact of e-consent on vaccine equity. The impact of e-consent on overall level of consent/ non-consent return was variable. Transitioning from paper to e-consent systems has been difficult for some parents and adolescents to adapt to. Further evaluations of e-consent are required to inform its use in vaccination processes. Although utilisation of e-consent could yield efficiencies in gathering of consent, evidence that it leads to any benefit in vaccination outcomes is very limited.

Background Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis are leading causes of invasive bacterial disease worldwide. The aims of this study were to measure post-COVID-19 pandemic changes in the incidence of disease caused by these bacterial pathogens and assess the evidence for any age- or serotype/group-specific changes. Methods Prospectively, cases of invasive disease from 2018-2023 were submitted to national and/or regional microbiology reference laboratories in each of 27 countries/territories. An effective pandemic period was estimated, and interrupted time series analyses quantified the effect of the introduction and withdrawal of pandemic containment measures. Disease incidence rates for S pneumoniae, H influenzae and N meningitidis were calculated, stratified by age and serotype/group. Streptococcus agalactiae was investigated as a comparator invasive pathogen not transmitted via the respiratory route. Findings The median duration of pandemic containment measures among all 27 countries was 22 months (range, 14-26 months). Withdrawal of containment measures led to significant increases in invasive disease for S. pneumoniae (42%, incidence rate ratio [IRR] 1.42, 1.30-1.55) and H influenzae (68%, IRR 1.68, 1.47-1.91), but not N meningitidis (15%, IRR 1.15, 0.92-1.44). In the post-pandemic period, the risk of H influenzae disease (risk ratio [RR] 1.02, 0.91-1.14) returned to the pre-pandemic risk. Conversely, for S pneumoniae (RR 0.91, 0.85-0.97) and N meningitidis (RR 0.61, 0.54-0.69) the risk of invasive disease was significantly below pre-pandemic risk. There was no evidence for changed rates of S. agalactiae disease. The distribution of invasive disease by age was broadly as expected, and age-stratified disease incidence by serotype/group was similar to pre-pandemic rates, but with some notable changes. Interpretation By 2023, while the risk of invasive disease caused by H influenzae returned to pre-pandemic levels, the risk of S pneumoniae and N meningitidis disease remained below pre-pandemic levels. Changes were observed in the post-pandemic incidence and age-stratified distributions of some serotypes/groups. Evidence before this study We searched PubMed, bioRxiv, and medRxiv for articles published up to 31 Dec 2019 (before the COVID-19 pandemic) that reported on the effects of containment measures implemented in response to a pandemic. We identified 262 papers by searching for ‘pandemic’ AND ‘microbial transmission’ OR ‘transmission’ AND ‘containment’ but none of these described the effects of implementing large-scale containment measures during a pandemic. The Invasive Respiratory Infection Surveillance (IRIS) Consortium previously reported that the incidence of invasive bacterial disease due to S pneumoniae, H influenzae and N meningitidis was significantly reduced when COVID-19 pandemic containment measures were implemented to control the transmission of SARS-CoV-2. Added value of this study We extended the previous analyses to estimate the effective containment measure period within each of 27 countries across six continents, and calculated rates of invasive bacterial disease after the pandemic containment measures were withdrawn. This demonstrated that invasive bacterial disease caused by all three pathogens increased once pandemic containment measures were removed and incidence rates exceeded the rates observed before the pandemic. Subsequently, disease caused by H influenzae generally returned to pre-pandemic rates, whilst disease caused by S pneumoniae and N meningitidis remained below pre-pandemic rates. Some serotype/group and age-specific changes were also observed for each of the pathogens. Implications of all the available evidence The COVID-19 pandemic had profound direct and indirect effects on global public health. The IRIS Consortium has shown that invasive bacterial disease caused by S pneumoniae, H influenzae and N meningitidis was also altered, and that changes in the circulating serotypes/groups were observed among countries participating in the IRIS Consortium. Whether or not these epidemiological changes persist, and to what extent they might affect bacterial vaccination coverage and disease rates, will be revealed over time and thus invasive disease due to these pathogens needs to be closely monitored. ### Competing Interest Statement CHI de Creteil, France received research grants from the French Public Health Agency, Pfizer, and MSD. University Hospitals Leuven, Belgium received consulting fees and payment for lectures from MSD. MH participated on a Data Safety Monitoring Board or Advisory Board for both Pfizer and MSD. MH also holds investigator-initiated grants from Pfizer and MSD paid to his institution. However, the sponsors had no role in the data analysis and content of the manuscript. The National Medicines Institute, Warsaw, Poland received funding from the National Science Centre, MSD, and Pfizer, and received equipment from The Great Orchestra of Christmas Charity Foundation, and the Clinical Microbiology Center Foundation. AK received payments from Pfizer for lectures. AS received payments from MSD and Pfizer for lectures and support for attending meetings and/or travel, and from MSD, Pfizer, and Sanofi Pasteur for participation in advisory boards. ABB received funding from MSD for IRIS pneumococcal genome sequencing. ABB was an unpaid advisor to the World Health Organisation providing expertise related to vaccines and antimicrobial resistance. ABB is an unpaid General Assembly member (2022 onwards), Board member from 2016-2022, and Secretary from 2018-2022 for the ISPPD Society. MD has received financial support to attend national scientific meetings. HH received a grant from Pfizer for molecular aspects of invasive pneumococcal disease. HH received consulting fees from Bons Secours Hospital Group (Ireland) to provide advice on hospital infection and control issues with a new build. HH received payment from Scottish Hospitals Enquiry for expert testimony related to healthcare ventilation and healthcare-associated infections. KAJ received personal royalties from GSK. TTL is an unpaid Board member for the European Society for Meningococcal and Haemophilus influenzae disease (EMGM), and the German Society for Hygiene and Microbiology (DGHM), committee for microbial systematics, population genetics and infection epidemiology (FG MIP). HCS received funding from Pfizer for a pneumococcal carriage project. HCS received funding for consultations on a Data Safety Monitoring Board or Advisory Board for MSD. MvdL received payment or honoraria from Pfizer and Merck and is a member of advisory boards for Pfizer, Merck and GSK. AvG is the chairperson for national NiTAG (NAGI) for South Africa. NvS received consulting fees from MSD, GSK, and Pfizer, and research funding from MSD, GSK, Pfizer, the Dutch Health Counsel, Amsterdam UMC, Argenx, and the Leducq Foundation, which are all directly paid to the institution. NvS holds a patent (WO 2013/020090 A3) on vaccine development against Streptococcus pyogenes. NvS is an unpaid scientific advisor to the ItsME foundation, and a scientific advisor to Rapua te me ngaro ka tau, but fees are paid to the University of Amsterdam. NvS holds personal stock in Genmab BV and Bank of America. JY received grant support from grants from MSD-USA (MISP Call), Pfizer and MEIJI; payment for travel expenses and meeting fees from MSD and Pfizer; and participated in MSD and Pfizer advisory boards. JS participated in an advisory board for MSD. JAV performs contract work for the Institute of Health Carlos III funded by Pfizer, and receives consulting fees from Pfizer, GSK and Sanofi Pasteur. MC received an Investigator Initiated Research grant from Pfizer (W1243730) which has been paid to the institution (Childrens Health Ireland). MC is part of a working group for The National Immunisation Advisory Committee (NIAC) in Ireland. KGK received funding from the European Society for Clinical Microbiology and Infectious Diseases to attend the ESCMID Global meeting in Barcelona April 2024 as a member of the Professional Affairs Committee. KGK is a member of the lcelandic State Communicable Disease and Prevention Committee. KGK has stocks in a start-up innovation company ArcanaBio that is developing novel diagnostic tests. CMA received payments for lectures from MSD and Sanofi-Pasteur. CMA received support from MSD, Pfizer and Sanofi-Pasteur to attend meetings. LC received support from MSD for attendance and travel to international symposium ISPPD-13, organized in South Africa in March 2024. ### Funding Statement The infrastructure for the IRIS Consortium was funded by a Wellcome Trust Investigator Award to ABB (grant number 206394/Z/17/Z). The IRIS databases are part of PubMLST, which is funded by a Wellcome Trust Biomedical Resource Grant awarded to MJCM, ABB, and KAJ (grant number 218205/Z/19/Z). DS received an Oxford Clarendon Scholarship covering University fees plus a stipend, and a fellowship from the Nuffield Department of Population Health. This work was also partially supported by: research funding from the Polish Ministry of Health and the Polish Ministry of Science and Higher Education to the National Medicines Institute, Poland; The Swiss National Reference Center for Invasive Pneumococci (NZPn) received funding from the Federal Office of Public Health; the Seoul National University College of Medicine received funding from Pfizer (grant number 69765907); the Robert Koch-Institute with funds of the German Federal Ministry of Health (funding code 1369-237) to the National Reference Centre for Meningococci and Haemophilus influenzae; the Instituto Nacional de Salud de Colombia (National Reference Laboratory); research funding from Pfizer and the European Centre for Disease Prevention and Control (ECDC) for pneumococcal surveillance work at the Irish Meningitis and Sepsis Reference Laboratory; financial support from Pfizer and Merck for invasive pneumococcal disease surveillance to the University Hospital RWTH Aachen. The funders had no role in data collection, analysis, interpretation, writing of the manuscript or the decision to submit. All authors agreed to be accountable for all aspects of the work. All authors had full access to all data in the study and the corresponding author (ABB) had final responsibility for the decision to submit this work for publication. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB (OxTREC) of the University of Oxford waived ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes It is not possible to share the study data because doing so would risk identifying individual cases of invasive disease in countries with small numbers of cases.

Recent studies suggest an increased risk of reinfection with the SARS-CoV-2 Omicron variant compared with previous variants, potentially due to an increased ability to escape immunity specific to older variants, high antigenic divergence of Omicron from earlier virus variants as well as its altered cell entry pathway. The present study sought to investigate epidemiological evidence for differential SARS-CoV-2 reinfection intervals and incidence rates for the Delta versus Omicron variants within Wales. Reinfections in Wales up to February 2022 were defined using genotyping and whole genome sequencing. The median inter-infection intervals for Delta and Omicron were 226 and 192 days, respectively. An incidence rate ratio of 2.17 for reinfection with Omicron compared to Delta was estimated using a conditional Poisson model, which accounted for several factors including sample collection date, age group, area of residence, vaccination and travel status. These findings are consistent with an increased risk of reinfection with the Omicron variant, and highlight the value of monitoring emerging variants that have the potential for causing further waves of cases.

In 2013, shingles vaccination was introduced in Wales as a routine immunisation programme for older adults. Invitation for this vaccination has historically been recommended but not mandated by vaccination policy. We surveyed general practices to investigate if invitations and reminders are associated with higher uptake of shingles vaccine. Using data from general practices, we calculated practice -level shingles vaccine uptake between 01/07/2021 and 31/06/2022 for registered patients aged 70 -84 years. We distributed an online survey via email to all general practices in Wales on their use of vaccination invitations and reminders, method of invitations, and characteristics of their vaccination delivery. We used linear regression to calculate coefficients and 95 %CI to measure associations between invitations and vaccine uptake, adjusting for key demographics, with a multi -level component to account for similarities between general practices within the same health board. Survey response rate was 37 % (143/384). Median vaccine uptake for responding general practices was 57 % (IQR 50 -68 %) compared to 58 % (IQR 48 -68 %) nationally.General practices inviting all eligible patients (n = 95) had a 9 % (95 %CI 6 -13 %) higher vaccination uptake compared to those inviting none or some (n = 48, p < 0.001). Of practices sending invitations, those who reminded all patients (n = 42) had a 6 % (95 %CI 1 -11 %, p = 0.02) higher uptake compared to those that reminded none (n = 30). Practice size was associated with higher uptake, with small practices (n = 11, p = 0.02) having coverage 9 % (95 %CI 2 -16 %) higher compared to the reference population (medium-sized practices, n = 78). General practices inviting and reminding all eligible patients for shingles vaccination have a higher uptake compared to those inviting and reminding only some or none. From September 2023, shingles vaccination policy in Wales has been updated to explicitly mandate effective universal call and recall mechanisms in general practices.

BACKGROUND:The 2022/23 influenza season in the United Kingdom saw the return of influenza to prepandemic levels following two seasons with low influenza activity. The early season was dominated by A(H3N2), with cocirculation of A(H1N1), reaching a peak late December 2022, while influenza B circulated at low levels during the latter part of the season. From September to March 2022/23, influenza vaccines were offered, free of charge, to all aged 2-13 (and 14-15 in Scotland and Wales), adults up to 49 years of age with clinical risk conditions and adults aged 50 and above across the mainland United Kingdom. METHODS:End-of-season adjusted vaccine effectiveness (VE) estimates against sentinel primary-care attendance for influenza-like illness, where influenza infection was laboratory confirmed, were calculated using the test negative design, adjusting for potential confounders. METHODS:Results In the mainland United Kingdom, end-of-season VE against all laboratory-confirmed influenza for all those > 65 years of age, most of whom received adjuvanted quadrivalent vaccines, was 30% (95% CI: -6% to 54%). VE for those aged 18-64, who largely received cell-based vaccines, was 47% (95% CI: 37%-56%). Overall VE for 2-17 year olds, predominantly receiving live attenuated vaccines, was 66% (95% CI: 53%-76%). CONCLUSION:The paper provides evidence of moderate influenza VE in 2022/23.

BACKGROUND:We report 2023/2024 season interim influenza vaccine effectiveness for three studies, namely, primary care in Great Britain, hospital settings in Scotland and hospital settings in England. METHODS:A test negative design was used to estimate vaccine effectiveness. RESULTS:Estimated vaccine effectiveness against all influenzas ranged from 63% (95% confidence interval 46 to 75%) to 65% (41 to 79%) among children aged 2-17, from 36% (20 to 49%) to 55% (43 to 65%) among adults 18-64 and from 40% (29 to 50%) to 55% (32 to 70%) among adults aged 65 and over. CONCLUSIONS:During a period of co-circulation of influenza A(H1N1)pdm09 and A(H3N2) in the United Kingdom, evidence for effectiveness of the influenza vaccine in both children and adults was found.

BACKGROUND:The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic. METHODS:For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere. FINDINGS:Overall, 116 841 cases were analysed: 76 481 in 2018-19, before the pandemic, and 40 360 in 2020-21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40-0·55), H influenzae (0·51; 0·40-0·66) and N meningitidis (0·26; 0·21-0·31), while no significant changes were observed for S agalactiae (1·02; 0·75-1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145-55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories. INTERPRETATION:COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies. FUNDING:Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization.

The uptake of COVID-19 vaccination in Wales is high at a population level but many inequalities exist. Household composition may be an important factor in COVID-19 vaccination uptake due to the practical, social, and psychological implications associated with different living arrangements. In this study, the role of household composition in the uptake of COVID-19 vaccination in Wales was examined with the aim of identifying areas for intervention to address inequalities. Records within the Wales Immunisation System (WIS) COVID-19 vaccination register were linked to the Welsh Demographic Service Dataset (WDSD; a population register for Wales) held within the Secure Anonymised Information Linkage (SAIL) databank. Eight household types were defined based on household size, the presence or absence of children, and the presence of single or multiple generations. Uptake of the second dose of any COVID-19 vaccine was analysed using logistic regression. Gender, age group, health board, rural/urban residential classification, ethnic group, and deprivation quintile were included as covariates for multivariable regression. Compared to two-adult households, all other household types were associated with lower uptake. The most significantly reduced uptake was observed for large, multigenerational, adult group households (aOR 0.45, 95%CI 0.43–0.46). Comparing multivariable regression with and without incorporation of household composition as a variable produced significant differences in odds of vaccination for health board, age group, and ethnic group categories. These results indicate that household composition is an important factor for the uptake of COVID-19 vaccination and consideration of differences in household composition is necessary to mitigate vaccination inequalities.