It is impossible to address the many complex needs of respiratory virus surveillance with a single system. Therefore, multiple surveillance systems and complementary studies must fit together as tiles in a “mosaic” to provide a complete picture of the risk, transmission, severity, and impact of respiratory viruses of epidemic and pandemic potential. Below we present a framework to assist national authorities to identify priority respiratory virus surveillance objectives and the best approaches to meet them; to develop implementation plans according to national context and resources; and to prioritize and target technical assistance and financial investments to meet most pressing needs.

Background and objectives: To re-activate infuneza sentinel surveillance system in Yemen after disruption related to repurposing for COVID-19 pandemic. WHO Country Office (CO) in collaboration with Yemen’s Ministry of Public Health and Population (MOPH&P) jointly conducted an assessment mission to assess the current situation of the influenza sentinel surveillance system and assess its capacity to detect influenza epidemics and monitor trends in circulating influenza and other respiratory viruses of epidemic and pandemic potential. This study presents the results of the assessment for three sentinel sites located in Aden, Taiz and Hadramout/Mukalla. Methodology: A mixed methods approach was used to guide the assessment process and to help achieve the objectives. Data was collected as follows: desk review of the sentinel sites records and data; interviews with stakeholders, including key informants and partners; and direct observation through field visits to the sentinel sites, MOPH&P and the Central Public Health Laboratory (CPHL). Two assessment checklists were used: assessment of sentinel sites for SARI surveillance, and checklist for assessment of availability of SARI sentinel surveillance. Results and conclusion: COVID19 has affected health systems and services, and this was demonstrated in this assessment. The influenza sentinel surveillance system in Yemen is not effectively functional, however there’s plenty of room for improvement if investment in the system’s restructuring, training, building technical and laboratory capacities, and conducting continuous and regular supervision visits.

As we approach the three-year anniversary of the pandemic, we are now facing a seasonal influenza epidemic after two years without one. In light of growing concerns over the potential risk of a “twindemic,” the Republic of Korea is currently experiencing the first peak of seasonal flu and the overall pattern is quite similar to that observed before the COVID-19 pandemic. Notably, no sudden or early increase in cases has been detected, which is unique compared to other countries.

Although there has been an effective seasonal influenza vaccine available for more than 60 years, influenza continues to circulate and cause illness. The Eastern Mediterranean Region (EMR) is very diverse in health systems capacities, capabilities, and efficiencies, which affect the performance of services, especially vaccinations, including seasonal influenza vaccination. In this article, we have analyzed data from a regional seasonal influenza survey conducted in 2022, Joint Reporting Form (JRF), and verified their validity by the focal points. We also compared our results with those of the regional seasonal influenza survey conducted in 2016. This analysis provides a comprehensive overview on country-specific influenza vaccination policies, vaccine delivery, and coverage in EMR. Fourteen countries (64%) had reported having a national seasonal influenza vaccine policy. About (44%) countries recommended influenza vaccine for all SAGE recommended target groups. Up to (69%) of countries reported that COVID-19 had an impact on influenza vaccine supply in the country, with most of them (82%) reporting increases in procurement and supply of influenza vaccine, with the other countries reporting decreases in procurement due to COVID-19. We suggest supporting countries to develop a roadmap for influenza vaccine uptake and utilization, assessment of barriers and burden of influenza, including measuring the economic burden to enhance vaccine acceptance.

Background: Saudi Arabia (SA) reported its first case of COVID-19 on 2 March 2020. Mortality varied nationwide: by 14 April 2020 Medina had 16% of SA’s total COVID-19 cases and 40% of all COVID-19 deaths. A team of epidemiologists investigated to identify factors impacting survival. Methods: We reviewed medical records from two hospitals: Hospital A in Medina and Hospital B in Dammam. All patients with a registered COVID-related death between 1 March -22 April 2020 were included. We collected data on demographics, chronic health conditions, clinical presentation and treatment. We analysed data using SPSS. Results: We identified 76 cases: 38 cases from each hospital. More fatalities were among non-Saudis at Hospital A (89%) versus Hospital B (82%, p<.001). Hypertension prevalence was higher among cases at Hospital A (42%) versus Hospital B (21%) (p<.05). We found statistically significant differences (p<.05) in symptoms at initial presentation among cases at Hospital A versus Hospital B, including: body temperature (38º C vs 37º C), heart rate (104 bpm vs 89 bpm), and regular breathing rhythms (61% vs 55%). Less cases (50%) at Hospital A received heparin versus Hospital B (97%, p-value< 0.001). Conclusion: Patients who died at Hospital A typically presented with more severe illness and were more likely to have underlying health conditions. Migrant workers may be at increased risk due to poorer baseline health and reluctance to seek care. This highlights the importance of cross-cultural outreach to prevent deaths. Health education efforts should be multilingual and accommodate all literacy levels.

ABSTRACT Introduction: Influenza is an acute viral infection with significant morbidity and mortality. Its occur annually each winter is called seasonal influenza and is preventable through safe vaccine. Aim: To know the epidemiological pattern of patients with seasonal influenza in Iraqi sentinel sites. Methods: A cross- sectional study carried out on records of patients who attended four sentinel sites and registered to have influenza-like illness (ILI) or severe acute respiratory infection (SARI), and laboratory investigated. Results: The total number of cases was 1124, 36.2% of them aged 19-39 years; 53.9% were female; 74.9% lived in urban areas; 64.3% diagnosed as ILI and 35.7% as SARI. 15.9% had diabetes, 12.7% had heart disease, 4.8% had asthma, 3% had a chronic lung disease, and 2% had hematological disease. 94.6% did not get influenza vaccine. About COVID-19 vaccine, 69.4% did not vaccinated, 3.5% get only 1 dose, and 27.1% completed 2 doses. Only the SARI cases needed admission, among them 95.7% were cured. 6.5% were diagnosed as influenza- A virus, 26.1% had COVID-19, and 67.5% were negative. Among those with influenza, 97.3% had H3N2 subtype, and 2.7% had H1N1 pdm09. Conclusions: The percentage of influenza virus in Iraq is relatively small. The age, classification of case (ILI or SARI), having diabetes, heart disease, or immunological disease, and taking COVID-19 vaccine have a significant association with influenza. Recommendations: It’s needed for similar sentinel sites in other health directorates and for rising health education about seasonal influenza and its vaccine.

Background. Despite the known relatively high disease burden of influenza, data are lacking regarding a critical epidemiological indicator, the case-fatality ratio. Our objective was to infer age-group and influenza (sub)type specific values by combining modelled estimates of symptomatic incidence and influenza-attributable mortality. Methods. The setting was the Netherlands, 2011/12 through 2019/20 seasons. Sentinel surveillance data from general practitioners and laboratory testing were synthesised to supply age-group specific estimates of incidence of symptomatic infection, and ecological additive modelling was used to estimated influenza-attributable deaths. These were combined in an Bayesian inferential framework to estimate case-fatality ratios for influenza A(H3N2), A(H1N1)pdm09 and influenza B, per 5-year age-group. Results. Case-fatality estimates were highest for influenza A(H3N2) followed by influenza B and then A(H1N1)pdm09, and were highest for the 85+ years age-group, at 4.76% (95% credible interval (CrI): 4.52-5.01%) for A(H3N2), followed by influenza B at 4.08% (95% CrI: 3.77-4.39%) and A(H1N1)pdm09 at 2.51% (95% CrI: 2.09-2.94%). For 55-59 through 85+ years, the case-fatality risk was estimated to double with every 3.7 years of age. Conclusions. These estimated case-fatality ratios, per influenza sub(type) and per age-group, constitute valuable information for public health decision-making, for assessing the retrospective and prospective value of preventative interventions such as vaccination, and for health economic evaluations.

Background Healthcare workers (HCWs) have suffered considerable morbidity and mortality during the COVID-19 pandemic. Few studies have evaluated Coronavac vaccine effectiveness (VE), particularly in eastern Europe, where the vaccine has been widely used. Methods We conducted a prospective cohort study among HCWs in seven hospitals in Baku, Azerbaijan between May 17 to December 1, 2021, to evaluate primary series (two-dose) CoronaVac VE against symptomatic SARS-CoV-2 infection. Participants completed weekly symptom questionnaires, provided nasal swabs for SARS-CoV-2 RT-PCR testing when symptomatic, and provided serology samples at enrolment that were tested for anti-spike and anti-nucleocapsid antibodies. We estimated VE as (1 – hazard ratio)*100 using a Cox proportional hazards model with vaccination status as a time-varying covariate. Results We enrolled 1582 HCWs. At enrolment, 1040 (66%) had received two doses of CoronaVac; 421 (27%) were unvaccinated. During the study period, 72 PCR-positive SARS-CoV-2 infections occurred; 36/39 (92%) sequenced samples were classified as delta variant. The adjusted primary series VE against COVID-19 illness was 29% (95% CI:-51%;67%). For the delta-predominant period, adjusted primary series VE was 19% (95% CI:-81%;64%). For the entire analysis period, adjusted primary series VE was 39% (95% CI:-40%;73%) for HCW vaccinated within 14–149 days, and 19% (95%CI:-81;63) for those vaccinated ≥150 days. Conclusions During a delta-predominant period in Azerbaijan, point estimates suggest that primary series CoronaVac protected nearly 1 in 3 HCWs against COVID-19, but this finding was not statistically significant. Our findings underscore the need to consider booster doses in individuals who have received primary series CoronaVac.

We analysed the influenza epidemic that occurred in Australia during the 2022 winter using an age-structured dynamic transmission model which accounts for past epidemics to estimate the population susceptibility to an influenza infection. We applied the same model to five European countries. Our analysis suggests Europe might experience an early and moderately large influenza epidemic. Also, differences may arise between countries, with Germany and Spain experiencing larger epidemics, than France, Italy and the UK, especially in children.

Background: Patients are admitted to the hospital for respiratory illness at different stages of their disease course. It is important to appropriately analyse this heterogeneity in surveillance data to accurately measure disease severity among those hospitalized. The purpose of this study was to determine if unique baseline clusters of influenza patients exist, and to examine the association between cluster membership and in-hospital outcomes. Methods: Patients hospitalized with influenza at two hospitals in Southeast Michigan during the 2017/2018 (n=242) and 2018/2019 (n=115) influenza seasons were included. Physiologic and laboratory variables were collected for the first 24 hours of the hospital stay. K-medoids clustering was used to determine groups of individuals based on these values. Multivariable linear regression or Firth’s logistic regression were used to examine the association between cluster membership and clinical outcomes. Results: Three clusters were selected for 2017/2018, mainly differentiated by blood glucose level. After adjustment, those in C171 had 5.6 times the odds of mechanical ventilator use than those in C172 (95%CI: 1.49,21.1) and a significantly longer mean hospital length of stay than those in both C172 (mean 1.5 days longer, 95%CI: 0.2,2.7) and C173 (mean 1.4 days longer, 95%CI: 0.3,2.5). Similar results were seen between the two clusters selected for 2018/2019. Conclusion: In this study of hospitalized influenza patients, we show that distinct clusters with higher disease acuity can be identified and could be targeted for evaluations of vaccine and influenza antiviral effectiveness against disease attenuation. The association of higher disease acuity with glucose level merits evaluation.

Background: COVID-19 vaccine is critical in preventing SARS-CoV-2 infection and transmission. However, obesity’s effect on immune responses to COVID-19 vaccines is still unknown. Methods: We performed a meta-analysis of the literature and compared immune responses to COVID-19 vaccines among persons with and without obesity. We used Pubmed, Embase, Web of Science, and Cochrane Library to identify all related studies up to April 2022. The Stata.14 software was used to analyze the selected data. Results: Totally, 11 studies were included in the present meta-analysis. Five of them provided absolute values of antibody titers in the obese group and non-obese group. Overall, we found that the obese population was significantly associated with lower antibody titers (SMD = -0.228, 95% CI (-0.437, -0.019), P<0.001) after COVID-19 vaccination. Significant heterogeneity was present in most pooled analyses but was reduced after subgroup analyses. No publication bias was observed in the present analysis. The Trim and Fill method did not change the results in the primary analysis. Conclusion: The present meta-analysis suggested that obesity was significantly associated with decreased responses to SARS-CoV-2 vaccines. Future studies should be performed to unravel this relationship to prevent COVID-19 infection and transmission.

Background There is a need for vaccines that can induce effective systemic, respiratory mucosal and cellular immunity to control the COVID-19 pandemic. We reported previously that a synthetic mucosal adjuvant SF-10 derived from human pulmonary surfactant works as an efficient antigen delivery vehicle to antigen presenting cells in the respiratory and gastrointestinal tracts and promotes induction of influenza virus antigen-specific serum IgG, mucosal IgA and cellular immunity. Methods The aim of the present study was to determine the effectiveness of a new administration method of intratracheal (IT) vaccine comprising recombinant SARS-CoV-2 spike protein 1 (S1) combined with SF-10 (S1-SF-10 vaccine) on systemic, local and cellular immunity in mice, compared with intramuscular injection (IM) of S1 with a potent adjuvant AS03 (S1-AS03 vaccine). Results S1-SF-10-IT vaccine induced S1-specific IgG and IgA in serum and lung mucosae. These IgG and IgA induced by S1-SF-10-IT showed significant protective immunity in a receptor binding inhibition test of S1 and angiotensin converting enzyme 2, a receptor of SARS-CoV-2, which were more potent and faster achievement than S1-AS03-IM. Enzyme-linked immunospot assay showed high numbers of S1-specific IgA and IgG secreting cells (ASCs) and S1-responsive IFN-γ, IL-4, IL-17A cytokine secreting cells (CSCs) in the spleen and lungs. S1-AS03-IM induced IgG ASCs and IL-4 CSCs in spleen higher than S1-SF10-IT, but the numbers of ASCs and CSCs in lungs were low and hardly detected. Conclusion Based on the need for effective systemic, respiratory and cellular immunity, the S1-SF-10-IT vaccine seems promising mucosal vaccine against respiratory infection of SARS-CoV-2.

Background Persons experiencing homelessness face increased risk of influenza as overcrowding in congregate shelters can facilitate influenza virus spread. Data regarding on-site influenza testing and antiviral treatment within homeless shelters remains limited. Methods We conducted a cluster-randomized stepped-wedge trial of point-of-care molecular influenza testing coupled with antiviral treatment with baloxavir or oseltamivir in residents of 14 homeless shelters in Seattle, WA, USA. Residents ≥3 months with cough or ≥2 acute respiratory illness (ARI) symptoms and onset <7 days were eligible. In control periods, mid-nasal swabs were tested for influenza by RT-PCR. The intervention period included on-site rapid molecular influenza testing and antiviral treatment for influenza-positives if symptom onset was <48 hours. The primary endpoint was monthly influenza virus infections in the control versus intervention period. Influenza whole genome sequencing was performed to assess transmission and antiviral resistance. Results During 11/15/2019–4/30/2020, and 11/2/2020–4/30/2021, 1,283 ARI encounters from 668 participants were observed. Influenza virus was detected in 51 (4%) specimens using RT-PCR, (A=14; B=37); 21 influenza virus infections were detected from 269 (8%) of intervention-eligible encounters by rapid molecular testing and received antiviral treatment. 37% of ARI-participant encounters reported symptom onset <48 hours. The intervention had no effect on influenza virus transmission (adjusted relative risk 1.73, 95% CI 0.50–6.00). Of 23 influenza genomes, 86% of A(H1N1)pdm09 and 81% of B/Victoria sequences were closely related. Conclusion Our findings suggest feasibility of influenza test-and-treat strategies in shelters. Additional studies would help discern an intervention effect during periods of increased influenza activity

Background We explored whether hospital-based surveillance is useful in detecting severe acute respiratory infection (SARI) clusters and how often these events result in outbreak investigation and community mitigation. Methods During May 2009– December 2020, physicians at 14 sentinel hospitals prospectively identified SARI clusters (i.e., ≥2 SARI cases who developed symptoms ≤10 days of each other and lived <30 minute walk or <3 km from each other). Oropharyngeal and nasopharyngeal swabs were tested for influenza and other respiratory viruses by rRT-PCR. We describe the demographic of persons within clusters, laboratory results, and outbreak investigations. Results Physicians identified 464 clusters comprising 1,427 SARI cases (range 0–13 clusters per month). Sixty percent of clusters had three, 23% had 2, and 17% had ≥4 cases. Their median age was 2 years (interquartile [IQR] 0.4–25) and 63% were male. Laboratory results were available for the 464 clusters a median 9 days (IQR = 6–13 days) after cluster identification. Less than one in five clusters had cases that tested positive for the same virus: RSV in 58 (13%), influenza viruses in 24 (5%), HMPV in 5 (1%), HPIV in 3 (0.6%), adenovirus in 2 (0.4%). While 102/464 (22%) had poultry exposure, none tested positive for influenza A(H5N1) or A(H7N9). None of the 464 clusters led to field deployments for outbreak response. Conclusions For 11 years, none of the hundreds of identified clusters led to emergency response. The value of this event-based surveillance might be improved by seeking larger clusters, with stronger epidemiologic ties or decedents.

Introduction: During the early phase of the coronavirus disease 2019 (COVID-19), remdesivir was only approved for hospitalized patients. Our institution developed hospital-based, outpatient infusion centers for selected hospitalized patients with COVID-19 who had clinical improvement to allow for early dismissal. The outcomes of patients who transitioned to complete remdesivir in the outpatient setting were examined. Methods: Retrospective study of all hospitalized adult patients with COVID-19 who received at least one dose of remdesivir from 11/6/2020 to 11/5/2021 at one of the Mayo Clinic hospitals. Results: Among 3,029 hospitalized patients who received treatment with remdesivir for COVID-19, the majority (89.5%) completed the recommended the five-day course. Among them, 2,169 (80%) completed treatment during hospitalization, while 542 (20.0%) patients were dismissed to complete remdesivir in outpatient infusion centers. Patients who completed the treatment in the outpatient setting had lower odds of death within 28 days (aOR 0.14, 95% CI 0.06-0.32, p<0.001). However, their rate of subsequent hospital encounters within 30 days was higher (aHR 1.88, 95% CI 1.27-2.79, p=0.002). Among patients treated with remdesivir only in the inpatient setting, the adjusted odds of death within 28 days were significantly higher among those who did not complete the 5-day course of remdesivir (aOR 2.07, 95% CI 1.45-2.95, p<0.001). Conclusions: This study describes the clinical outcomes of a strategy of transitioning remdesivir therapy from inpatient to outpatient among selected patients. Mortality was lower among patients who completed the 5-day course of remdesivir.

Background: In 2021–22, influenza A viruses dominated in Europe. The I-MOVE primary care network conducted a multicentre test-negative study to measure influenza vaccine effectiveness (VE). Methods: Primary care practitioners collected information on patients presenting with acute respiratory infection. Cases were influenza A(H3N2) or A(H1N1)pdm09 RT-PCR positive and controls were influenza virus negative. We calculated VE using logistic regression, adjusting for study site, age, sex, onset date, and presence of chronic conditions. Results: Between week 40 2021 and week 20 2022, we included over 11,000 patients of whom 253 and 1595 were positive for influenza A(H1N1)pdm09 and A(H3N2), respectively. Overall VE against influenza A(H1N1)pdm09 was 75% (95%CI: 43–89) and 81% (95%CI: 44–93) among those aged 15–64 years. Overall VE against influenza A(H3N2) was 29% (95%CI: 12–42) and 25% (95%CI: -41–61), 33% (95%CI: 14–49) and 26% (95% CI: -22 to 55) among those aged 0–14, 15–64 and over 65 years, respectively. The A(H3N2) VE among the influenza vaccination target group was 20% (95%CI: -6–39). All 53 sequenced A(H1N1)pdm09 viruses belonged to clade 6B.1A.5a.1. Among 410 sequenced influenza A(H3N2) viruses, all but 8 belonged to clade 3C.2a1b.2a.2. Discussion: Despite antigenic mismatch between vaccine and circulating strains for influenza A(H3N2) and A(H1N1)pdm09, 2021–22 VE estimates against circulating influenza A(H1N1)pdm09 were the highest within the I-MOVE network since the 2009 influenza pandemic. VE against A(H3N2) was lower than A(H1N1)pdm09, but at least one in five individuals vaccinated against influenza were protected against presentation to primary care with laboratory-confirmed influenza.

Background Sarajevo Canton in the Federation of Bosnia and Herzegovina has recorded several waves of high SARS-CoV-2 transmission and has struggled to reach adequate vaccination coverage. We describe the evolution of infection- and vaccine-induced SARS-CoV-2 antibody response and persistence. Methods We conducted repeated cross-sectional analyses of blood donors aged 18-65 years in Sarajevo Canton in November-December 2020 and 2021. We analyzed serum samples for anti-nucleocapsid (anti-N) and anti-spike (anti-S) antibodies. To assess immune durability, we conducted longitudinal analyses of seropositive participants at 6 and 12 months. Results 1015 participants were included in Phase 1 (November-December 2020), and 1152 in Phase 2 (November-December 2021). Seroprevalence increased significantly from 19.2% (95% CI: 17.2-21.4%) in Phase 1 to 91.6% (95% CI: 89.8-93.1%) in Phase 2. Anti-S IgG titers were significantly higher among vaccinated (58.5%) than unvaccinated infected participants across vaccine products (p<0.001), though highest among those who received an mRNA vaccine. At 6 months, 78/82 (95.1%) participants maintained anti-spike seropositivity; at 12 months, 58/58 (100.0%) participants were seropositive and 33 (56.9%) had completed the primary vaccine series within 6 months. Among 11 unvaccinated participants who were not reinfected at 12 months, anti-S IgG declined from median 770.1 (IQR 615.0-1321.7) to 290.8 (IQR 175.7-400.3). Anti-N IgG antibodies waned earlier; from 35.4% seropositive at 6 months to 24.1% at 12 months. Conclusions SARS-CoV-2 seroprevalence increased significantly over 12 months from end of 2020 to end of 2021. Although individuals with previous infection may have residual protection, COVID-19 vaccination is vital to strengthening population immunity.

Background: Measures introduced during the COVID-19 pandemic intended to address the spread of SARS-CoV-2 may also influence the incidence of other common seasonal respiratory viruses (SRV). This evaluation reports laboratory confirmed cases of common SRV in a well-defined region of central Canada to address this issue. Methods: Surveillance data for common non-SARS-CoV-2 SRV in the Ottawa, Canada region was provided by the Eastern Ontario Regional Laboratory Association (EORLA) reference virology lab. Weekly reports of the number of positive tests and proportion that yielded positive results was analyzed from August 26, 2018 to January 2, 2022. Results: A drastic reduction in influenza and other common SRV was observed during the 2020-2021 influenza season in the Ottawa region. Influenza was virtually undetected post SARS-CoV-2 emergence. Rhinoviruses and enteroviruses were the only viruses that remained relatively unaffected during this period. Conclusions: We speculated that the introduction of non-pharmaceutical measures including masking to prevent SARS-CoV-2 transmission contributed to the near absence of SRV in the Ottawa region. These measures should remain a key component in addressing spikes in SRV activity and future pandemics.