Influenza Sentinel Surveillance Research Articles

Use of Sentinel Surveillance Platforms for Monitoring SARS-CoV-2 Activity: Evidence From Analysis of Kenya Influenza Sentinel Surveillance Data.

Little is known about the cocirculation of influenza and SARS-CoV-2 viruses during the COVID-19 pandemic and the use of respiratory disease sentinel surveillance platforms for monitoring SARS-CoV-2 activity in sub-Saharan Africa. We aimed to describe influenza and SARS-CoV-2 cocirculation in Kenya and how the SARS-CoV-2 data from influenza sentinel surveillance correlated with that of universal national surveillance. From April 2020 to March 2022, we enrolled 7349 patients with severe acute respiratory illness or influenza-like illness at 8 sentinel influenza surveillance sites in Kenya and collected demographic, clinical, underlying medical condition, vaccination, and exposure information, as well as respiratory specimens, from them. Respiratory specimens were tested for influenza and SARS-CoV-2 by real-time reverse transcription polymerase chain reaction. The universal national-level SARS-CoV-2 data were also obtained from the Kenya Ministry of Health. The universal national-level SARS-CoV-2 data were collected from all health facilities nationally, border entry points, and contact tracing in Kenya. Epidemic curves and Pearson r were used to describe the correlation between SARS-CoV-2 positivity in data from the 8 influenza sentinel sites in Kenya and that of the universal national SARS-CoV-2 surveillance data. A logistic regression model was used to assess the association between influenza and SARS-CoV-2 coinfection with severe clinical illness. We defined severe clinical illness as any of oxygen saturation <90%, in-hospital death, admission to intensive care unit or high dependence unit, mechanical ventilation, or a report of any danger sign (ie, inability to drink or eat, severe vomiting, grunting, stridor, or unconsciousness in children younger than 5 years) among patients with severe acute respiratory illness. Of the 7349 patients from the influenza sentinel surveillance sites, 76.3% (n=5606) were younger than 5 years. We detected any influenza (A or B) in 8.7% (629/7224), SARS-CoV-2 in 10.7% (768/7199), and coinfection in 0.9% (63/7165) of samples tested. Although the number of samples tested for SARS-CoV-2 from the sentinel surveillance was only 0.2% (60 per week vs 36,000 per week) of the number tested in the universal national surveillance, SARS-CoV-2 positivity in the sentinel surveillance data significantly correlated with that of the universal national surveillance (Pearson r=0.58; P<.001). The adjusted odds ratios (aOR) of clinical severe illness among participants with coinfection were similar to those of patients with influenza only (aOR 0.91, 95% CI 0.47-1.79) and SARS-CoV-2 only (aOR 0.92, 95% CI 0.47-1.82). Influenza substantially cocirculated with SARS-CoV-2 in Kenya. We found a significant correlation of SARS-CoV-2 positivity in the data from 8 influenza sentinel surveillance sites with that of the universal national SARS-CoV-2 surveillance data. Our findings indicate that the influenza sentinel surveillance system can be used as a sustainable platform for monitoring respiratory pathogens of pandemic potential or public health importance.

Epidemic trends and prevention and control of seasonal influenza in China after the COVID-19 pandemic

During the COVID-19 pandemic, a series of non-pharmaceutical interventions, which were implemented to curb the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), significantly modified the seasonal pattern of influenza. The intensity of influenza activity markedly decreased and B/Yamagata lineage was no longer detected. As the national influenza sentinel surveillance data shown, clear seasonal patterns were observed for influenza between 2012-2019, annually with an average of 14.57% of specimens tested positive for influenza virus. However, the seasonal pattern of influenza was disrupted after the outbreak of COVID-19. In the 2020-2021 season, influenza demonstrated an extremely low activity (yearly positivity rate<1.0%), followed by a resurgence of winter peak in the 2021-2022 season. Following the downgrade of management of COVID-19 to Class B in China in December 26, 2022, social activities gradually resumed, leading to the rebound of influenza activity with an out-of-season ciculation. After COVID-19 pademic, other respiratory infectious diseases caused by SARS-CoV-2, respiratory syncytial virus, and mycoplasma pneumonia were alternatively or concurrently circulated with influenza. The prevention and control of influenza and other respiratory infectious diseases emphasizes a multi-disease prevention strategy, including long-term and continuous monitoring the epidemic trends in influenza virus and SARS-CoV-2, promoting influenza and COVID-19 vaccination among key populations, and strengthening the knowledge and public awareness of prevention and control for respiratory infectious diseases, etc.

Prevalence of respiratory syncytial virus infection and associated factors in children aged under five years with severe acute respiratory illness and influenza-like illness in Ethiopia

ObjectivesAcute respiratory infections because of respiratory syncytial viruses (RSVs) are among the major leading causes of morbidity and mortality in children worldwide. RSV prevalence and its contributing factors among children aged under 5 years in Ethiopia are not well studied. To assess the prevalence and associated factors of RSV infection in children aged under 5 years using influenza sentinel surveillance sites in Ethiopia. MethodsA cross-sectional study design was used utilizing influenza-like illness/sever acute respiratory illness surveillance data from January 2021 to December 2022 at the Ethiopian Public Health Institute. ResultsIn total, 2234 cases were included, with an overall RSV positivity rate of 16.2%. The RSV positivity rate was high in children aged under 1 year (22.8%) and during fall season (24.8%). The RSV positivity rate was significantly associated with ages under 1 year (adjusted odds ratio [AOR] 2.8, 95% confidence interval [CI]: 1.89-4.15) and 1-2 years (AOR 1.9, 95% CI: 1.26-2.73) and the fall season (AOR 1.67, 95% CI: 1.17-2.38). ConclusionThe study revealed that a considerably high RSV positivity rate was detected in children aged under 5 years. The age of children and season have a significant association with RSV positivity rate. Further studies of RSV viral genotype, clinical characteristics, and disease outcome need to be conducted for a better understanding of the virus and disease outcome.

Epidemiology of influenza in Nigeria: A secondary analysis of the sentinel surveillance data in Nigeria from 2010 – 2020

BackgroundInfluenza is a leading cause of morbidity and mortality globally. Little is known of the true burden and epidemiology of influenza in Africa. Nigeria has a sentinel surveillance system for influenza virus (IFV). This study seeks to describe the epidemiological characteristics of influenza cases in Nigeria through secondary data analysis of the sentinel surveillance data from 2010 to 2020. MethodologyA retrospective secondary data analysis of data collected from patients with influenza-like illness (ILI) and severe acute respiratory infection (SARI) in the four Nigeria Influenza Sentinel Surveillance sites from January 2010 to December 2020. Data was cleaned and analyzed using Microsoft Excel and Epi info 7.2 for frequencies and proportions. The results of the analysis were summarized in tables and charts. ResultsA total of 13,828 suspected cases of influenza were recorded at the sentinel sites during the study period. About 10.3% (1421/13,828) of these tested positive for IFV of which 1243 (87.5%) were ILI patients, 175 (12.3%) SARI patients, and 3 (0.2%) novel H1N1 patients. Males accounted for 54.2% (770/1421) of the confirmed cases. The median age of confirmed cases was 3 years (range: <1month–97 years). Children 0–4 years accounted for 69.3% (985/1421) of all cases. The predominant subtypes were B lineage not determined (32.3%), A/H1N1 pdm09 (28.8%) and A/H3 (23.0%). There were periods of sustained transmission in most years with 2011 having the highest number of cases. Overall, there were more cases around January to March and August to November. Heart disease and chronic shortness of breath were the most common co-morbidities identified among confirmed cases. ConclusionInfluenza remains a significant cause of respiratory illness, especially among children aged less than 4 years. Influenza cases occur all year round with irregular seasonality in Nigeria. Children less than 4 years and those with co-morbidities should be prioritized for vaccination. Vaccine composition in the country should take cognizance of the prevailing strains which are type B (lineage not determined), A/H1N1 pdm09 and A/H3.

Integration of SARS-CoV-2 testing and genomic sequencing into influenza sentinel surveillance in Uganda, January to December 2022.

Respiratory pathogens cause high rates of morbidity and mortality globally and have high pandemic potential. During the SARS-CoV-2 pandemic, influenza surveillance was significantly interrupted because of resources being diverted to SARS-CoV-2 testing and sequencing. Based on recommendations from the World Health Organization, the Uganda Virus Research Institute, National Influenza Center laboratory integrated SARS-CoV-2 testing and genomic sequencing into the influenza surveillance program. We describe the results of influenza and SARS-CoV-2 testing of samples collected from 16 sentinel surveillance sites located throughout Uganda as well as SARS-CoV-2 testing and sequencing in other health centers. The surveillance system showed that both SARS-CoV-2 and influenza can be monitored in communities at the national level. The integration of SARS-CoV-2 detection and genomic surveillance into the influenza surveillance program will help facilitate the timely release of SARS-CoV-2 information for COVID-19 pandemic mitigation and provide important information regarding the persistent threat of influenza.

Introducing seasonal influenza vaccine in Bhutan: Country experience and achievements

Bhutan successfully introduced multiple vaccines since the establishment of the Vaccine Preventable Disease Program in 1979. Surveillance and subsequent introduction of influenza vaccination became a public health priority for the Ministry of Health following the influenza A(H1N1)pdm09 pandemic. Sentinel surveillance for influenza in Bhutan began in 2008, and a study of severe acute respiratory infection was conducted in 2017, which found the highest influenza burden in children aged <5 years and adults ≥50 years. Following review of surveillance and burden of disease data, the National Technical Advisory Group presented recommendations to Bhutan’s Ministry of Health which approved influenza vaccine introduction for all five high-risk groups in the country. Upon the official launch of the program in June 2018, the Vaccine Preventable Disease Program began planning, budgeting, and procurement processes with technical and financial support from the Partnership for Influenza Vaccine Introduction, the United States Centers for Disease Control and Prevention, the Bhutan Health Trust Fund, and the World Health Organization. Influenza vaccination for high-risk groups was integrated into Bhutan’s routine immunization services in all health care facilities beginning in November 2019 and vaccinated all populations in 2020 in response to the COVID-19 pandemic. Coverage levels between 2019 and 2022 were highest in children aged 6–24 months (62.5%–96.9%) and lowest in pregnant women (47.7%–62.5%). Bhutan maintained high coverage levels despite the COVID-19 pandemic by continued provision of influenza vaccine services at health centers during lockdowns, conducting communication and sensitization efforts, and using catch-up campaigns. Bhutan’s experience with introducing and scaling up the influenza vaccine program contributed to the country’s capacity to rapidly deploy its COVID-19 vaccination program in 2021.

First identification of the SARS-COV-2/XBB.1.5 sublineage among indigenous COVID-19 cases through the influenza sentinel surveillance system in Niger

The emergence of the Omicron variant in November 2021, has caused panic worldwide due to the rapid evolution and the ability of the virus to escape the immune system. Since, several Omicron sublineages (BA.1 to BA.5) and their descendent recombinant lineages have been circulating worldwide. Furthermore, in December 2022, a new Omicron subvariant XBB.1.5 characterized by an unusual mutation in the spike protein evolved in the United States and rapidly spread to the other continents. Our study reports on the first cases of XBB.1.5 sublineage among indigenous Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-COV-2) positive cases detected through the influenza sentinel surveillance system in Niger. All influenza suspected cases were tested for both influenza and SARS-COV-2 using the Centre for Disease Control and prevention (CDC) Influenza SARS-COV-2 Multiplex quantitative Reverse-Transcription Polymerase Chain Reaction (qRT-PCR) Assay. SARS-COV-2 positive samples with cycle threshold ≤28 were selected for whole genome sequencing subsequently using the Oxford Nanopore Midnight protocol with rapid barcoding on a MinIon MK1B device. A total of 51 SARS-COV-2 positive samples were confirmed between December 2022 and March 2023. We successfully obtained 19 sequences with a predominance of the XBB.1/XBB.1.5 sublineages (73.7 %). In addition, a recombinant XBD sequence was also first-ever identified in early March 2023. Our findings support the need to strengthen the influenza sentinel surveillance for routine Coronavirus Disease 2019 (COVID-19) surveillance and SARS-COV-2 variants monitoring in Niger.

Lessons learned from identifying clusters of severe acute respiratory infections with influenza sentinel surveillance, Bangladesh, 2009-2020.

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. 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 min walk or <3 km from each other). Oropharyngeal and nasopharyngeal swabs were tested for influenza and other respiratory viruses by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We describe the demographic of persons within clusters, laboratory results, and outbreak investigations. Field staff identified 464 clusters comprising 1427 SARI cases (range 0-13 clusters per month). Sixty percent of clusters had three, 23% had two, and 17% had ≥4 cases. Their median age was 2 years (inter-quartile range [IQR] 0.4-25) and 63% were male. Laboratory results were available for the 464 clusters with a median of 9 days (IQR = 6-13 days) after cluster identification. Less than one in five clusters had cases that tested positive for the same virus: respiratory syncytial virus (RSV) in 58 (13%), influenza viruses in 24 (5%), human metapneumovirus (HMPV) in five (1%), human parainfluenza virus (HPIV) in three (0.6%), adenovirus in two (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. For 11 years, none of the hundreds of identified clusters led to an emergency response. The value of this event-based surveillance might be improved by seeking larger clusters, with stronger epidemiologic ties or decedents.

Factors associated with hospitalization for seasonal influenza in Morocco.

Morocco is actively working towards expanding its influenza vaccine policy to cover high-risk groups, as recommended by the World Health Organization (WHO). We assessed the risk factors for influenza-associated hospitalization for severe acute respiratory infections (SARI) that occurred during the last 5 seasons. We conducted a retrospective, analytical study among patients recruited in the ambulatory and hospital sites of the influenza sentinel surveillance system in Morocco between 2014 and 2019. Using multiple logistic regression, we compared the characteristics of influenza-positive patients with SARI to those with influenza-like illness (ILI) to identify factors associated with severe disease. We included 1323 positive influenza patients with either SARI (41.7%) or ILI diagnosis (58.3%). A(H1N1)pdm09, A(H3N2) and influenza B, respectively, contributed 49.2%, 29.5% and 20.6% of the cases. The main risk factors considered in the bivariate analysis were found in the multivariate analysis to be significantly associated with influenza-related hospitalization (SARI): age < 2 years (aOR = 7.08, P < 0.001); age ≥ 65 years (aOR = 3.59, P < 0.001); diabetes (aOR = 1.98, P = 0.017); obesity (aOR = 2.94, P = 0.034); asthma or chronic respiratory disease (aOR = 4.99, P < 0.001); chronic renal failure (aOR = 4.74, P = 0.005); pregnancy (aOR = 7.49, P < 0.001); and the A(H1N1)pdm09 subtype (aOR = 1.82, P < 0.001). This study provides epidemiological evidence for the expected benefit of an influenza vaccination strategy for high-risk groups as recommended by the WHO.

Comprehensive surveillance of acute respiratory infections during the COVID-19 pandemic: a methodological approach using sentinel networks, Castilla y León, Spain, January 2020 to May 2022.

BackgroundSince 1996, epidemiological surveillance of acute respiratory infections (ARI) in Spain has been limited to seasonal influenza, respiratory syncytial virus (RSV) and potential pandemic viruses. The COVID-19 pandemic provides opportunities to adapt existing systems for extended surveillance to capture a broader range of ARI.AimTo describe how the Influenza Sentinel Surveillance System of Castilla y León, Spain was rapidly adapted in 2020 to comprehensive sentinel surveillance for ARI, including influenza and COVID-19.MethodsUsing principles and methods of the health sentinel network, we integrated electronic medical record data from 68 basic surveillance units, covering 2.6% of the regional population between January 2020 to May 2022. We tested sentinel and non-sentinel samples sent weekly to the laboratory network for SARS-CoV-2, influenza viruses and other respiratory pathogens. The moving epidemic method (MEM) was used to calculate epidemic thresholds.ResultsARI incidence was estimated at 18,942 cases per 100,000 in 2020/21 and 45,223 in 2021/22, with similar seasonal fold increases by type of respiratory disease. Incidence of influenza-like illness was negligible in 2020/21 but a 5-week epidemic was detected by MEM in 2021/22. Epidemic thresholds for ARI and COVID-19 were estimated at 459.4 and 191.3 cases per 100,000 population, respectively. More than 5,000 samples were tested against a panel of respiratory viruses in 2021/22.ConclusionExtracting data from electronic medical records reported by trained professionals, combined with a standardised microbiological information system, is a feasible and useful method to adapt influenza sentinel reports to comprehensive ARI surveillance in the post-COVID-19 era.

The Impact of the COVID-19 Pandemic on Influenza Transmission in Poland.

The aim of this study was to determine whether the occurrence of the SARS-CoV-2 pandemic affected the incidence of influenza in Poland and the efficiency of the SENTINEL influenza surveillance system. The analysis was based on virologic data from the 2018/2019-2021/2022 epidemic seasons. The data in question were obtained from the SENTINEL influenza surveillance system, which is utilized in Poland. In the 2020/2021 epidemic season, only one positive case was confirmed. In the epidemic season of 2021/2022, the number of positive cases increased. There was a delay in the peak of the season, since the start of pandemic, which was observed in the 14th week of 2022. Previously, it was recorded in the 5-10th week, depending on the season. Before the pandemic, the number of positive samples in relation to the tested ones oscillated between 41-49.4%. After the pandemic, it was 0.3% and below 20%, respectively, for season 2020/2021 and season 2021/2022. The COVID-19 pandemic caused a decline in many other infectious diseases, including influenza, as a result of the numerous lockdowns and from people shifting to remote work. Other safety measures, such as obligatory protective masks and the use of disinfectants, had a significant impact on reducing the number of cases.

An assessment of the current epidemiological and laboratory capacities for influenza‐like illnesses and severe acute respiratory infection surveillance, Yemen 2022

We aim to re-activate influenza 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. A mixed methods approach was used to guide the assessment process and to help achieve the objectives. Data were 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. COVID-19 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 is 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.

Эпидемиологическая характеристика ОРВИ и гриппа на территории Казахстана в эпидемические сезоны с 2018 по 2022 год

One of the most important medical and socio-economic problems worldwide is the incidence of influenza and acute respiratory viral infections (ARVI). The urgency of the problem is due to their widespread prevalence, economic costs, the high probability of a complicated course and exacerbation of chronic non-communicable diseases, the variability of viruses, and the formation of bacterial-associated respiratory diseases against their background. In recent years, the simultaneous circulation of influenza A(H1N1), A(H3N2) and type B influenza viruses has been observed during the epidemiological season. The COVID-19 pandemic has affected the situation of the incidence of ARVI and influenza in the Kazakhstan. Objective. To assess the epidemic situation in Kazakhstan during the epidemic seasons 2018–2019, 2019–2020, 2020–2021, and 2021–2022 and to identify influenza pathogens circulating among the population. Materials and methods. Epidemiological surveillance for ARVI and influenza in Kazakhstan includes several components. The routine system of registering ARVI cases based on appeal is carried out by organizations providing primary medical care. In 2008, epidemiological surveillance for ARVI and influenza was supplemented with sentinel epidemiological surveillance. Sentinel surveillance for influenza, ARVI, influenza-like illness, and SARS is carried out year-round, and the incidence of influenza in outpatients and inpatients is monitored. Records are kept of all requests for medical care in age groups of 0–4, 5–14, 15–29, 30–64, 65 years and older. During the research, the results of regular monitoring in the surveillance system for influenza, ARVI, influenza-like illness, and SARS in four seasons of ARVI and influenza incidence (epidemic seasons from 2018–2019 to 2021–2022, from 40 weeks of the first year to 20 weeks of the second year) were used. Data on the incidence of ARVI and influenza, the results of laboratory tests of the weekly monitoring of the Reference Laboratory for the Control of Viral Infections of the Scientific and Practical Center for Sanitary and Epidemiological Expertise and Monitoring and 16 regional virological laboratories of branches of the National Center for Expertise, combined into a single Information system "Tracking ARVI/influenza/pneumonia", were taken into account. During the study period, coverage in the Republic of Kazakhstan amounted to 2,408,525 cases of ARVI and influenza, including 93,233 hospitalizations. A total of 39,251 samples were examined for influenza, of which 5,553 PCR tests were positive. Sampling for sequencing is carried out after PCR, while samples with a high concentration of viral RNA (Сt ≤25) are taken. Sequencing methods are used for genotyping of influenza viruses. The research methods also included a molecular genetic study of samples from patients with ARVI and influenza. Results. The highest incidence rates of ARVI and influenza were observed in the epidemic season of 2021–2022, with their maximum levels recorded from the 40th to the 51st week and from the 3rd to the 5th week. In the epidemiological seasons 2018–2019 and 2019–2020, the influenza A(H1N1)pdm09 virus dominated, followed by the influenza A(H3N2) virus and the active circulation of the influenza B virus. In the 2020–2021 epidemiological season, 6,564 PCR studies of samples for the presence of the SARS-CoV-2 virus were conducted in the Republic of Kazakhstan, of which 421 (6%) were positive samples, and in the 2021-2022 epidemiological season – 820 (4%). Conclusion. The results of the analysis show that the circulation of influenza and other ARVI pathogens in the epidemiological season continues to play a leading role in the etiology of respiratory viral infections. Key words: influenza viruses, SARS-CoV-2 virus, influenza, morbidity, ARVI, epidemiological situation

Influenza hospitalisations in Spain between the last influenza and COVID-19 pandemic (2009-2019).

Knowing the burden of severe disease caused by influenza is essential for disease risk communication, to understand the true impact of vaccination programmes and to guide public health and disease control measures. We estimated the number of influenza-attributable hospitalisations in Spain during the 2010-2011 to 2019-2020 seasons - based on the hospitalisations due to severe acute respiratory infection (SARI) in Spain using the hospital discharge database and virological influenza information from the Spanish Influenza Sentinel Surveillance System (SISSS). The weekly numbers of influenza-attributable hospitalisations were calculated by multiplying the weekly SARI hospitalisations by the weekly influenza virus positivity, obtained from the SISSS in each season, stratified by age group and sex. The influenza-related hospitalisation burden is age-specific and varies significantly by influenza season. People aged 65 and over yielded the highest average influenza-attributable hospitalisation rates per season (615.6 per 100,000), followed by children aged under 5 (251.2 per 100,000). These results provide an essential contribution to influenza control and to improving existing vaccination programmes, as well as to the optimisation and planning of health resources and policies.

Multisite surveillance for influenza and other respiratory viruses in India: 2016-2018.

There is limited surveillance and laboratory capacity for non-influenza respiratory viruses in India. We leveraged the influenza sentinel surveillance of India to detect other respiratory viruses among patients with acute respiratory infection. Six centers representing different geographic areas of India weekly enrolled a convenience sample of 5-10 patients with acute respiratory infection (ARI) and severe acute respiratory infection (SARI) between September 2016-December 2018. Staff collected nasal and throat specimens in viral transport medium and tested for influenza virus, respiratory syncytial virus (RSV), parainfluenza virus (PIV), human meta-pneumovirus (HMPV), adenovirus (AdV) and human rhinovirus (HRV) by reverse transcription polymerase chain reaction (RT-PCR). Phylogenetic analysis of influenza and RSV was done. We enrolled 16,338 including 8,947 ARI and 7,391 SARI cases during the study period. Median age was 14.6 years (IQR:4-32) in ARI cases and 13 years (IQR:1.3-55) in SARI cases. We detected respiratory viruses in 33.3% (2,981) of ARI and 33.4% (2,468) of SARI cases. Multiple viruses were co-detected in 2.8% (458/16,338) specimens. Among ARI cases influenza (15.4%) were the most frequently detected viruses followed by HRV (6.2%), RSV (5%), HMPV (3.4%), PIV (3.3%) and AdV (3.1%),. Similarly among SARI cases, influenza (12.7%) were most frequently detected followed by RSV (8.2%), HRV (6.1%), PIV (4%), HMPV (2.6%) and AdV (2.1%). Our study demonstrated the feasibility of expanding influenza surveillance systems for surveillance of other respiratory viruses in India. Influenza was the most detected virus among ARI and SARI cases.

Influenza surveillance systems using traditional and alternative sources of data: A scoping review

While the World Health Organization's recommendation of syndromic sentinel surveillance for influenza is an efficient method to collect high-quality data, limitations exist. Aligned with the Research Recommendation 1.1.2 of the WHO Public Health Research Agenda for Influenza-to identify reliable complementary influenza surveillance systems which provide real-time estimates of influenza activity-we performed a scoping review to map the extent and nature of published literature on the use of non-traditional sources of syndromic surveillance data for influenza. We searched three electronic databases (PubMed, Web of Science, and Scopus) for articles in English, French, and Spanish, published between January 1 2007 and January 28 2022. Studies were included if they directly compared at least one non-traditional with a traditional influenza surveillance system in terms of correlation in activity or timeliness. We retrieved 823 articles of which 57 were included for analysis. Fifteen articles considered electronic health records (EHR), 11 participatory surveillance, 10 online searches and webpage traffic, seven Twitter, five absenteeism, four telephone health lines, three medication sales, two media reporting, and five looked at other miscellaneous sources of data. Several articles considered more than one non-traditional surveillance method. We identified eight categories and a miscellaneous group of non-traditional influenza surveillance systems with varying levels of evidence on timeliness and correlation to traditional surveillance systems. Analyses of EHR and participatory surveillance systems appeared to have the most agreement on timeliness and correlation to traditional systems. Studies suggested non-traditional surveillance systems as complements rather than replacements to traditional systems.

Rapidly adapting primary care sentinel surveillance across seven countries in Europe for COVID-19 in the first half of 2020: strengths, challenges, and lessons learned.

As the COVID-19 pandemic began in early 2020, primary care influenza sentinel surveillance networks within the Influenza - Monitoring Vaccine Effectiveness in Europe (I-MOVE) consortium rapidly adapted to COVID-19 surveillance. This study maps system adaptations and lessons learned about aligning influenza and COVID-19 surveillance following ECDC / WHO/Europe recommendations and preparing for other diseases possibly emerging in the future. Using a qualitative approach, we describe the adaptations of seven sentinel sites in five European Union countries and the United Kingdom during the first pandemic phase (March–September 2020). Adaptations to sentinel systems were substantial (2/7 sites), moderate (2/7) or minor (3/7 sites). Most adaptations encompassed patient referral and sample collection pathways, laboratory testing and data collection. Strengths included established networks of primary care providers, highly qualified testing laboratories and stakeholder commitments. One challenge was the decreasing number of samples due to altered patient pathways. Lessons learned included flexibility establishing new routines and new laboratory testing. To enable simultaneous sentinel surveillance of influenza and COVID-19, experiences of the sentinel sites and testing infrastructure should be considered. The contradicting aims of rapid case finding and contact tracing, which are needed for control during a pandemic and regular surveillance, should be carefully balanced.

Influenza activity in the Eastern Mediterranean Region (EMR) in 2020–2021 amidst the COVID-19 pandemic

IntroductionA global reduction in influenza virus activity during the COVID-19 pandemic has been observed, including in the Eastern Mediterranean Region (EMR). However, these changes have not been thoroughly evaluated scientifically...

Surveillance of influenza B severe hospitalized cases during 10 seasons in Catalonia: Does the lineage make a difference?

Influenza B viruses circulate in two lineages (B/Victoria and B/Yamagata). Although classically affecting children, recently it has shown a high rate of infection and increased hospitalization in the elderly. To describe and analyze the clinical and epidemiological characteristics of severe hospitalized laboratory-confirmed influenza B virus (SHLCI-B) cases in Catalonia associated with mismatch from Influenza B virus strain included in the trivalent influenza vaccine (TIV). SHLCI-B was registered by the influenza sentinel surveillance system of Catalonia (PIDIRAC) during ten surveillance seasons from 2010 to 2020. Variables age, comorbidities, and vaccination status were recorded. Vaccine effectiveness was estimated as (1-OR) for intensive care unit (ICU) admission. Statistical significance was established at p < 0.05. A total of 1159 SHLCI-B were registered, of these 68.2% (791) corresponded to the 2017-2018 season; 21.8% (253) were admitted to ICU and 13.8% (160) were exitus; 62.5% (725) cases occurred in those aged >64 years; most frequent risk factor was cardiovascular disease (35.1%, 407) followed by chronic pulmonary obstructive disease-COPD (24.6%, 285) and diabetes (24.1%, 279). In four seasons, the predominant circulating lineage was B/Victoria, in two seasons the B/Yamagata lineage and four seasons had no IBV activity. Four seasons presented discordance with the strain included within the TIV. Vaccine effectiveness (VE) to prevent ICU admission was 31% (95% confidence interval [CI]: 4%-51%; p = 0.03); being 29% (95% CI: -3% to 51%) in discordant and 43% (95% CI:-43% to 77%) in concordant seasons. Significant differences were observed in the number of affected aged > 64 years (odds ratio [OR] = 2.5; 95% CI: 1.9-3.4; p < 0.001) and in patients with heart disease (OR = 2.40 95% CI: 1.7-3.4; p < 0.001), COPD (OR = 1.6 95% CI: 1.1-2.3; p = 0.01), and diabetes (OR = 1.5 95% CI: 1.1-2.1; p = 0.04) between discordant and concordant seasons. The increase in hospitalization rate in people> 64 years of age and those presenting comorbidities in seasons with circulating influenza B virus belonging to a lineage discordant with the strain included in the TIV and the decrease of VE to prevent ICU admissions evidence the vital need to administer the quadrivalent influenza vaccine regardless of the findings of predominant circulation in the previous season.

Sentinel surveillance for influenza A viruses in Lahore District Pakistan in flu season 2015\u20132016

BackgroundInfluenza A virus (IAV) remains an important global public health threat with limited epidemiological information available from low-and-middle-income countries. The major objective of this study was to describe the proportions, temporal and spatial distribution, and demographic and clinical characteristics of IAV positive patients with influenza like illness (ILI) and severe acute respiratory illness (SARI) in Lahore, Pakistan.MethodsProspective surveillance was established in a sentinel hospital from October 2015 to May 2016. All eligible outpatients and inpatients with ILI or SARI were enrolled in the study. Nasal and/or throat swabs were collected along with clinico-epidemiological data. Samples were tested by real-time RT-PCR (rRT-PCR) to identify IAV and subtype. The descriptive analysis of data was done in R software.ResultsOut of 311 enrolled patients, 284 (91.3%) were ILI and 27 (8.7%) were SARI cases. A distinct peak of ILI and SARI activity was observed in February. Fifty individuals (16%) were positive for IAV with peak positivity observed in December. Of 50 IAV, 15 were seasonal H3N2, 14 were H1N1pdm09 and 21 were unable to be typed. The majority of IAV positive cases (98%) presented with current or history of fever, 88% reported cough and 82% reported sore throat. The most common comorbidities in IAV positive cases were hepatitis C (4%), obesity (4%) and tuberculosis (6%). The highest incidence of patients reporting to the hospital was seen three days post symptoms onset (66/311) with 14 of these (14/66) positive for IAV.ConclusionDistinct trends of ILI, SARI and IAV positive cases were observed which can be used to inform public health interventions (vaccinations, hand and respiratory hygiene) at appropriate times among high-risk groups. We suggest sampling from both ILI and SARI patients in routine surveillance as recommended by WHO.