Dynamics of influenza seasonality at sub-regional levels in India and implications for vaccination timing

Severe acute respiratory infections: An epidemiological analysis of surveillance data in Bahrain, 2018-2022

Background

Severe acute respiratory tract infections (SARI) pose a health threat to children and adults worldwide. The SARI surveillance program was initiated in 2018 in Bahrain to monitor the activity of respiratory pathogens. Salmaniya Medical Complex (SMC) was chosen as the sentinel site for the SARI surveillance program. This study aimed to describe the epidemiology of SARI patients admitted to SMC from 2018 to 2022.

Methods

Patients meeting the World Health Organization definition of SARI and presenting with cough and fever within the last 10 days and admitted to SMC from January 2018 until December 2022 were included in the study. Epidemiological data on SARI cases were collected from SARI surveillance data and analyzed using SPSS version 25 and Excel.

Results

A total of 1362 SARI cases were enrolled from January 2018 to the end of December 2022; the majority were males (57.7%, n = 786). The highest SARI incidence rates were recorded among individuals over 65 years old (155.5 per 100,000) in 2021 and among those under 5 years old (887 per 100,000) in 2020. About half of the patients had at least one comorbidity (54.0%, n = 735), with diabetes (23.0%, n = 313) and hypertension (17.2%, n = 234) being the most common. The highest number of cases was observed in 2021 (27%, n = 373), followed by 2018 (20%, n = 267). A viral pathogen was detected in 30.7% (n = 418) of the SARI patients. The most prevalent pathogen was influenza A (11.5%, n = 156), followed by SARS-CoV-2 (9.7%, n = 132), respiratory syncytial virus (RSV) (5.1%, n = 69), and influenza B (3.9%, n = 53). The highest percentage of SARI cases was recorded in the winter months, mainly January (17%, n = 236). The percentages of influenza A and RSV cases were highest in December, at 22% (n = 39) and 14% (n = 25), respectively. Influenza B cases were recorded predominantly in March (9%, n = 11).

Conclusion

The incidence of SARI was highest among patients above 65 years old. The majority had comorbidities. Influenza and respiratory syncytial viruses were the most frequent causes of SARI, with influenza A being the most prevalent. December and January were the months with the highest SARI cases and viral detection rates. Promoting vaccination, timely testing, and prompt treatment, especially for the elderly and those with comorbidities, is key to reducing SARI-related morbidity and mortality, especially during peak seasons.

Incidence of Hospitalization due to Influenza-Associated Severe Acute Respiratory Infection During 2010-2019 in Bangladesh

BACKGROUND

Global influenza-associated acute respiratory infections contribute to 3-5 million severe illnesses requiring hospitalization annually, with 90% of hospitalizations occurring among children < 5 years in developing countries. In Bangladesh, the inadequate availability of nationally representative, robust estimates of influenza-associated hospitalizations limits allocation of resources for prevention and control measures.

METHODS

This study used data from the hospital-based influenza surveillance (HBIS) system in Bangladesh from 2010 to 2019 and healthcare utilization surveys to determine hospital utilization patterns in the catchment area. We estimated annual influenza-associated hospitalization numbers and rates for all age groups in Bangladesh using WHO methods, adjusted for a 6-day-a-week enrollment schedule, selective testing of specimens from children under five, and healthcare-seeking behavior, based on the proportion of symptomatic community participants seeking healthcare within the past week. We then estimated national hospitalization rates by multiplying age-specific hospitalization rates with the corresponding annual national census population.

RESULTS

Annual influenza-associated hospitalization rates per 100,000 population for all ages ranged from 31 (95% CI: 27-36) in 2011 to 139 (95% CI: 130-149) in 2019. Children < 5 years old had the highest rates of influenza-associated hospitalization, ranging from 114 (95% CI: 90-138) in 2011 to 529 (95% CI: 481-578) in 2019, followed by adults aged ≥ 65 years with rates ranging from 46 (95% CI: 34-57) in 2012 to 252 (95% CI: 213-292) in 2019. The national hospitalization estimates for all ages during 2010-2019 ranged from 47,891 to 236,380 per year.

CONCLUSIONS

The impact of influenza-associated hospitalizations in Bangladesh may be considerable, particularly for young children and older adults. Targeted interventions, such as influenza vaccination for these age groups, should be prioritized and evaluated.

Influence of COVID-19 over seasonal influenza activity in southern India

Basic epidemiological data is urgently needed in order to ascertain the changes brought about by COVID-19 pandemic, and help researchers, clinicians, and policy makers in addressing these issues. Data on influenza positivity from 2009 to 2019 was collected from Regional Influenza laboratory, JIPMER. Being COVID testing centre we tested samples (2020-2023) from Tamilnadu and Pondicherry. All SARI samples which were negative for COVID-19 were subjected to Influenza testing as regular surveillance activity was suspended. On comparison we found significant reduction in detection rates of influenza A H1N1, H3N2 and influenza B (p value = <0.01).

Combination therapy of nitazoxanide with oseltamivir compared with oseltamivir in hospitalized patients with seasonal influenza

Antiviral combinations have been proposed as treatment for influenza in order to increase the antiviral activity by action at different sites of action as well as obviate the emergence of drug resistance to the commonly used antiviral agents like oseltamivir. Nitazoxanide has been found to exhibit anti-influenza viral activity with clinical benefit in a previous study. We recruited 242 cases of SARI, among whon 67 were confirmed to have influenza viral infection. In a randomized blinded fashion, 34 patients received a combination of nitazoxanide and oseltamivir whereas 33 cases received oseltamivir alone. Clinical parameters were followed in both groups and the nasal swabs were re-tested on day 6 for influenza positivity and the cycle threshold (CT) values. No significant differences were observed in terms of time for resolution of fever, other symptoms, and SOFA scores. Nine patients succumbed during the course of the illness that included three in the oseltamivir group and six in the combination group. All but one of those who expired had an underlying co-morbid illness. Our preliminary data suggest that the addition of nitazoxanide does not improve outcomes in hospitalized patients with influenza. Larger studies are recommended for statistically robust conclusions.

Prevalence and Characteristics of Influenza Cases From 2017 to 2019 at a Tertiary Care Teaching Hospital in Karnataka

Introduction Influenza virus is a significant human pathogen causing severe acute respiratory illness (SARI) associated with significant mortality worldwide. The H1N1 Influenza virus that caused a pandemic in 2009 continued to cause periodic epidemics worldwide, with new variants posing significant public health problems. The present study was carried out to determine the prevalence and characteristics of influenza at a tertiary care teaching hospital. Methods From 2017 to 2019, respiratory samples from suspected cases of influenza belonging to category C received at the microbiology laboratory were transported to Manipal Centre for Virus Research, Manipal, in the cold chain for testing of influenza virus by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) as per CDC guidelines. The microbiological reports were collected and evaluated. The details of patients positive for influenza were analyzed for demographic and clinical characteristics. Results During the study period, 172 samples from SARI patients were tested, out of which 44 patients were positive for the influenza virus, accounting for a prevalence of 25.58%; 84% (n=37) of the cases were infected with H1N1 influenza virus, and the other 11.36% (n=5) and 4.54% (n=2) cases yielded H1N2 and H1N3 influenza virus, respectively. Among 44 patients, 56.81% (n=25) were females and 43.18% (n=19) were males. Most of the patients, 65.9% (n=29), were between 40 and 60 years old. The predominant presenting symptoms were fever in 81.81% (n=36) patients, breathlessness in 56.8% (n=25) patients, and cough in 54.54% (n=24) patients. Twelve (27.27%) patients had acute severe respiratory distress syndrome (ARDS). A significant mortality rate of 22.72% (n=10) was noted in the study. Conclusion A significant prevalence of influenza was noted in the study at 25.58%. Along with the H1N1 Influenza virus, the new strains detected in our region were H1N2 and H1N3 influenza viruses. Regular surveillance is important in the early detection of cases, for timely management, to reduce mortality, and to take measures to prevent the spread of this important infectious disease.

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

IMPORTANCE

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.

The role of vaccination and environmental factors on outbreaks of high pathogenicity avian influenza H5N1 in Bangladesh

High Pathogenicity Avian Influenza (HPAI) H5N1 outbreaks continue to wreak havoc on the global poultry industry and threaten the health of wild bird populations, with sporadic spillover in humans and other mammals, resulting in widespread calls to vaccinate poultry. Bangladesh has been vaccinating poultry since 2012, presenting a prime opportunity to study the effects of vaccination on HPAI H5N1circulation in both poultry and wild birds. We investigated the efficacy of vaccinating commercial poultry against HPAI H5N1 along with climatic and socio-economic factors considered potential drivers of HPAI H5N1 outbreak risk in Bangladesh. Using a multivariate modeling approach, we estimated that the rate of outbreaks was 18 times higher before compared to after vaccination, with winter months having a three times higher chance of outbreaks than summer months. Variables resulting in small but significant increases in outbreak rate were relatively low ambient temperatures for the time of year, literacy rate, chicken and duck density, crop density, and presence of highways; this may be attributable to low temperatures supporting viral survival outside the host, higher literacy driving reporting rate, density of the host reservoir, and spread of the virus through increased connectivity. Despite the substantial impact of vaccination on outbreaks, we note that HPAI H5N1 is still enzootic in Bangladesh; vaccinated poultry flocks have high rates of H5N1 prevalence, and spillover to wild birds has increased. Vaccination in Bangladesh thus bears the risk of supporting "silent spread," where the vaccine only provides protection against disease and not also infection. Our findings underscore that poultry vaccination can be part of holistic HPAI mitigation strategies when accompanied by monitoring to avoid silent spread.

Pan-India influenza-like illness (ILI) and Severe acute respiratory infection (SARI) surveillance: epidemiological, clinical and genomic analysis

Background

Over time, COVID-19 testing has significantly declined across the world. However, it is critical to monitor the virus through surveillance. In late 2020, WHO released interim guidance advising the use of the existing Global Influenza Surveillance and Response System (GISRS) for the integrated surveillance of influenza and SARS-CoV-2.

Methods

In July 2021, we initiated a pan-India integrated surveillance for influenza and SARS-CoV-2 through the geographically representative network of Virus Research and Diagnostic Laboratories (VRDLs) across 26 hospital and laboratory sites and 70 community sites. A total of 34,260 cases of influenza-like illness (ILI) and Severe acute respiratory infection (SARI) were enrolled from 4 July 2021 to 31 October 2022.

Findings

Influenza A(H3) and B/Victoria dominated during 2021 monsoon season while A(H1N1)pdm09 dominated during 2022 monsoon season. The SARS-CoV-2 "variants of concern" (VoC) Delta and Omicron predominated in 2021 and 2022, respectively. Increased proportion of SARI was seen in extremes of age: 90% cases in < 1 year; 68% in 1 to 5 years and 61% in ≥ 8  years age group. Approximately 40.7% of enrolled cases only partially fulfilled WHO ILI and SARI case definitions. Influenza- and SARS-CoV-2-infected comorbid patients had higher risks of hospitalization, ICU admission, and oxygen requirement.

Interpretation

The results depicted the varying strains and transmission dynamics of influenza and SARS-CoV-2 viruses over time, thus emphasizing the need to continue and expand surveillance across countries for improved decision making. The study also describes important information related to clinical outcomes of ILI and SARI patients and highlights the need to review existing WHO ILI and SARI case definitions.

Clinical profile of influenza virus-related hospitalizations in children aged 1-59 months: A five-year retrospective study from south India

BACKGROUND

Influenza is a seasonal acute respiratory tract infection with different strains in circulation at different time periods with varying spectrum of clinical presentation.

OBJECTIVES

To study the clinical presentation, morbidity, and mortality patterns associated with different strains of influenza virus, to identify the predominant strains related to hospitalization, and to identify the seasonal trend in hospitalization and risk factors for mortality in children aged 1-59 months hospitalized with influenza.

MATERIALS AND METHODS

The records of children hospitalized with influenza were analyzed retrospectively (June 2013 to June 2018). Anonymized data from the Medical Records Department of our Institute, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), were used for the study and waiver of consent was obtained from the Institute Ethics Committee for Human Studies (JIPMER), which also approved the study. The data from the medical records were extracted as per the proforma and entered into Microsoft excel and summary statistics was obtained. Categorical data were expressed as proportion and analyzed using chi square test. Association was tested using odds ratio.

RESULTS

Of the 693 children tested for influenza during the study period, 91 were found to be positive for influenza infection and out of which 68 (74.7%) were hospitalized. Infection was seen during both the summer and winter months. The predominant strain being A (H1N1) pdm09 (63.2%). The other strains found were A (H3N2) and Influenza B. The predominant diagnosis was pneumonia. The need for mechanical ventilation was more common with influenza B infection (p = 0.035). No significant risk factors for mortality could be found in our study.

CONCLUSION

An absence of seasonal predilection for the disease was noted with influenza A (H1N1) pdm09 being the predominant strain with influenza B seen as an emerging strain and an important contributor towards morbidity.

Repeatability and timing of tropical influenza epidemics

Much of the world experiences influenza in yearly recurring seasons, particularly in temperate areas. These patterns can be considered repeatable if they occur predictably and consistently at the same time of year. In tropical areas, including southeast Asia, timing of influenza epidemics is less consistent, leading to a lack of consensus regarding whether influenza is repeatable. This study aimed to assess repeatability of influenza in Vietnam, with repeatability defined as seasonality that occurs at a consistent time of year with low variation. We developed a mathematical model incorporating parameters to represent periods of increased transmission and then fitted the model to data collected from sentinel hospitals throughout Vietnam as well as four temperate locations. We fitted the model for individual (sub)types of influenza as well as all combined influenza throughout northern, central, and southern Vietnam. Repeatability was evaluated through the variance of the timings of peak transmission. Model fits from Vietnam show high variance (sd = 64-179 days) in peak transmission timing, with peaks occurring at irregular intervals and throughout different times of year. Fits from temperate locations showed regular, annual epidemics in winter months, with low variance in peak timings (sd = 32-57 days). This suggests that influenza patterns are not repeatable or seasonal in Vietnam. Influenza prevention in Vietnam therefore cannot rely on anticipation of regularly occurring outbreaks.

Prevalence and Predictors for Respiratory Viral Infections among Liver Disease Patients

Aim and background

Respiratory viral infections (RVIs) cause significant hospitalizations every year. Also, RVIs caused by either influenza or noninfluenza group of viruses can have adverse outcomes, especially among immunosuppressed patients. Regular and timely supervision is needed for accurate etiological identification, to prevent inappropriate use of antibiotics in patients with nonbacterial etiology. This study aimed to identify the spectrum of RVIs and clinical characteristics among liver disease patients with influenza-like illness (ILI).

Materials and methods

In this study, medical records of patients with ILI, whose requests for respiratory viral testing came from September 2016 to December 2022 were retrospectively reviewed. Respiratory viruses were identified using FilmArray 2.0 respiratory panel (BioFire Diagnostics, USA).

Results

Of the 1,577 liver disease patients with ILI, the overall prevalence of RVI was 28% (n = 449). Infection by noninfluenza viruses (NIVs) was detected in 329 patients (73%), higher than those infected with influenza viruses. In multivariable logistic regression analysis, female gender [odds ratio (OR): 2.5, 95% confidence interval (CI): 1.5-4.2], infection with influenza B (OR: 3.3, 95% CI: 1.09-9.9) and decompensated cirrhosis (OR: 3.9, 95% CI: 1.7-8.5) were independent risk factors for mortality. Regarding seasonality, influenza peaked in monsoons and winters, whereas NIVs circulated throughout the year.

Conclusion

Overall, this study adds new knowledge regarding the incidence of RVI and the distribution of respiratory viral etiologies among liver disease patients with ILI. The findings highlight that female gender, decompensated cirrhosis, and influenza B infection are independently associated with poor clinical outcomes. Early etiological identification of viral causes of ILI could aid in an enhanced understanding of the prevalence of ILI and the timely management of the patients.

Clinical significance

Respiratory viral infections can cause severe illness in individuals with underlying liver disease. Accurate diagnosis and risk stratification is crucial in mitigating the adverse health effects.

How to cite this article

Samal J, Prabhakar T, Prasad M, et al. Prevalence and Predictors for Respiratory Viral Infections among Liver Disease Patients. Euroasian J Hepato-Gastroenterol 2023;13(2):108-114.

Safety and Protective Effects of Influenza Vaccination in Pregnant Women on Pregnancy and Birth Outcomes in Pune, India: A Cross-Sectional Study

BACKGROUND

Maternal influenza vaccination provides effective protection against influenza infections in pregnant women and their newborns. In India, the influenza vaccine has not yet been offered through immunization programs, owing to the lack of sufficient safety data for pregnant Indian women.

METHODS

This cross-sectional observational study enrolled 558 women admitted to the obstetrics ward of a civic hospital in Pune. Study-related information was obtained from the participants through hospital records and interviews using structured questionnaires. Univariate and multivariable analysis was used, and the chi-square test with adjusted odds ratio was estimated to account for vaccine exposure and the temporal nature of each outcome, respectively.

RESULTS

Women not vaccinated against influenza during pregnancy had a higher risk of delivering very LBW infants, and possible protective effects were suggested (AOR 2.29, 95% CI 1.03 to 5.58, p = 0.03). No association was observed between maternal influenza vaccination for Caesarean section (LSCS) (AOR 0.97, 95% CI, 0.78, 1.85), stillbirth (AOR 1.8, 95% CI 0.18, 24.64) and NICU admission (AOR, 0.87, 0.29 to 2.85), and congenital anomaly (AOR, 0.81, 0.10 to 3.87).

INTERPRETATION

These results show that the influenza vaccine administered during pregnancy is safe and might lower the risk of negative birth outcomes.

Estimation of seasonal influenza disease burden using sentinel site data in Pakistan 2017–2019: A cross‐sectional study

Background

The influenza A(H1N1)pdm09 pandemic highlighted the need for reliable disease burden estimation from low‐ and middle‐income countries like Pakistan. We designed retrospective age‐stratified estimation of influenza‐related severe acute respiratory infections (SARIs) incidence in Islamabad Pakistan 2017–2019.

Materials and Methods

The catchment area was mapped on SARI data from one designated influenza sentinel site and other healthcare facilities in the Islamabad region. The incidence rate was calculated as per 100,000 for each age group with 95% confidence interval.

Results

The catchment population for the sentinel site was 0.7 million against the total denominator of 1.015 million, and incidence rates were adjusted. During January 2017 to December 2019, among 13,905 hospitalizations, 6715 (48%) patients were enrolled; 1208 of these (18%) were positive for influenza. During 2017, influenza A/H3 dominated with 52% detections followed by A(H1N1)pdm09 (35%) and influenza B (13%). Furthermore, elderly 65+ years age group had highest hospitalizations and influenza positive. The incidence rates of all cause respiratory and influenza‐related SARI were highest among children >5 years; highest incidence was found in 0 to 11 month/year group with 424/100,000 cases and lowest in 5–15 years 56/100,000. The estimated average annual influenza‐associated hospitalization percentage was 29.3% during the study period.

Conclusion

Influenza accounts for a significant proportion of respiratory morbidity and hospitalization. These estimates would enable governments for evidence‐based decisions and priority allocation of health resources. It is necessary to test for other respiratory pathogens for more clear disease burden estimation.

Model Development and Prediction of Covid-19 Pandemic in Bangladesh with Nonlinear Incident

We introduce a SEIRD compartmental model to analyze the dynamics of the pandemic in Bangladesh. The multi-wave patterns of the new infective in Bangladesh from the day of the official confirmation to August 15, 2021, are simulated in the proposed SEIRD model. To solve the model equations numerically, we use the RK-45 method. Primarily, we establish some theorems including local and global stability for the proposed model. The analysis shows that the death curve simulated by the model provides a very good agreement with the officially confirmed death data for the Covid-19 pandemic in Bangladesh. Furthermore, the proposed model estimates the duration and peaks of Covid-19 in Bangladesh which are compared with the real data.

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.

The influences of the East Asian Monsoon on the spatio-temporal pattern of seasonal influenza activity in China

Previous research has extensively studied the seasonalities of human influenza infections and the effect of specific climatic factors in different regions. However, there is limited understanding of the influences of monsoons. This study applied generalized additive model with monthly surveillance data from mainland China to explore the influences of the East Asian Monsoon on the spatio-temporal pattern of seasonal influenza in China. The results suggested two influenza active periods in northern China and three active periods in southern China. The study found that the northerly advancement of East Asian Summer Monsoon (EASM) influences the summer influenza spatio-temporal patterns in both southern and northern China. At the interannual scale, the north-south converse effect of EASM on influenza activity is mainly due to the converse effect of EASM on humidity and precipitation. Within the annual scale, influenza activity in southern China gradually reaches its maximum during the summer exacerbated by the northerly advancement of EASM. Furthermore, the winter epidemic in China is related to the low temperature and humidity influenced by the East Asian Winter Monsoon (EAWM). Moreover, the active period in transition season is related partially to the large rapid temperature change influenced by the transition of EAWM and EASM. Despite the delayed onset and instability, the climatic condition influenced by the East Asian Monsoon is one of the potential key drivers of influenza activity.

Influenza virus and its subtypes circulating during 2018-2019: A hospital-based study from Assam

PURPOSE

Influenza virus can cause serious respiratory illness sometimes resulting in epidemics and pandemics associated with significant morbidity and mortality across the globe. Hence, continuous surveillance of the activity of the influenza virus and its subtypes is necessary to help the policy makers to take effective and appropriate decisions regarding its control. The study aimed to determine distribution of influenza viruses in Assam of north-east India having subtropical climate that may lead to viral subtype divergence.

METHODS

Clinically suspected ninety cases with Influenza like illness (ILI) were included, irrespective of age and sex during the period 1st July 2018 to 30th June 2019. Aseptically collected Nasopharyngeal swabs in viral transport media (VTM) were tested by conventional Reverse Transcriptase Polymerase Chain Reaction (RT PCR) for detection of Influenza A and Influenza B viruses which were further processed for detection of subtypes such as H1N1 pdm09, H3N2 and Influenza B (Yamagata and Victoria lineage). Normally distributed continuous variables were summarised by mean and standard deviation. All categorical variables were summarised as percentages.

RESULTS

Influenza activity was seen in 42.2% of ILI cases with male predominance (57.9%). Influenza A was the predominant type (84.2%). Among the subtypes, A(H1N1) pdm09 was predominant (76.3%) followed by Influenza B (Victoria lineages) (15.8%) and AH3N2 (7.9%). Significant difference was observed between different subtypes with regard to age distribution only. Influenza activity in Assam showed two seasonal peaks; the primary one from May to July and the secondary from November to February.

CONCLUSION

The study described the distribution of different Influenza viruses and its subtypes in Assam along with their seasonal activities. These findings will help to formulate the policy for its prevention and control in Assam as well as to monitor the efficacy of the current influenza vaccine.

Susceptibility to the Common Cold Virus is Associated with Day Length

Seasonal rhythms are endogenous timing mechanisms that allow animals living at temperate latitudes to synchronize their physiology to the seasons. Human viral respiratory disease is prevalent in the winter at temperate latitudes, but the role of endogenous mechanisms in these recurring annual patterns is unclear. The Common Cold Project is a repository of data describing the experimental viral challenge of 1,337 participants across the seasons of the year. We report a secondary analysis of these data to investigate if susceptibility to the common cold is associated with day length. The majority of the participants (78%) showed signs of infection but only 32% developed clinical signs of disease, and the probability of infection was significantly higher in longer day lengths (summer), but the disease was more likely in short (winter) day lengths. The persistence of winter disease patterns in experimental conditions supports the role of endogenous seasonality in human susceptibility to viral infection.

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Outbreaks of viral respiratory disease recur in winter in the northern hemisphere

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In controlled experiments, common cold infection was more likely in summer

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Infection was more likely to progress to the development of cold in winter

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Innate seasonality of human immunity could affect the prevalence of the common cold

SARS-CoV-2 and Influenza Virus Co-Infection Cases Identified through ILI/SARI Sentinel Surveillance: A Pan-India Report

SARS-CoV-2/influenza virus co-infection studies have focused on hospitalized patients who usually had grave sequelae. Here, we report SARS-CoV-2/influenza virus co-infection cases from both community and hospital settings reported through integrated ILI/SARI (Influenza Like Illness/Severe Acute Respiratory Infection) sentinel surveillance established by the Indian Council of Medical Research. We describe the disease progression and outcomes in these cases. Out of 13,467 samples tested from 4 July 2021–31 January 2022, only 5 (0.04%) were of SARS-CoV-2/influenza virus co-infection from 3 different sites in distinct geographic regions. Of these, three patients with extremes of age required hospital admission, but none required ICU admission or mechanical ventilation. No mortality was reported. The other two co-infection cases from community settings were managed at home. This is the first report on SARS-CoV-2/Influenza virus co-infection from community as well as hospital settings in India and shows that influenza viruses are circulating in the community even during COVID-19. The results emphasize the need for continuous surveillance for multiple respiratory pathogens for effective public health management of ILI/SARI cases in line with the WHO (World Health Organization) recommendations.

The Epidemiological Pattern and Co-infection of Influenza A and B by Surveillance Network From 2009 to 2014 in Anhui Province, China

Influenza-like illness (ILI) is one of the most important public health problems globally, causing an enormous disease burden. Influenza infections are the most common cause of ILI. Bacterial and virus co-infection is common yet the data of co-infection with influenza A and B viruses are scarce. To identify the epidemiological patterns of and co-infection of influenza A and B in Anhui province, China, we analyzed the surveillance data of 5 years from 2009 to 2014 collected by the Chinese National influenzas network. The results showed that the weekly ratio of ILI was 3.96 ± 1.9% (95% CI 3.73–4.2%) in outpatients and the highest affected population was children under 5 years old. The epidemic of influenza viruses was highest during 2009–2010. For the other 4 surveillance years, school-aged people (5–14 years) were the most highly affected population. Influenza B and H3N2 viruses were more prevalent than H1N1pdm09 virus after 2010. In addition, a significant co-circulation of influenza A (H1N1pdm09 and H3N2) and influenza B virus was detected with 0.057% PCR positive rate during 2009–2014 in Eastern China, yet isolated only in pediatric patients. Our data reveals school-aged population would be the main vulnerable population and a distinct seasonality for influenza. In addition, the co-infection of influenza A and B were found in Anhui Province, China. Ongoing surveillance is critical to understand the seasonality variation and make evidence-based vaccination recommendations. Information on the epidemiological patterns and co-infections of influenza A and B can help us to implement different strategies for selecting vaccine formulations and monitoring new emerging influenza strains. In addition, the identification of the susceptible population can help us to develop more precise protection measures.

A comparative analysis of the epidemiology of influenza and respiratory syncytial virus in Russia, 2013/14 to 2018/19

Background

Influenza and respiratory syncytial virus (RSV) are among the leading causes of lower respiratory tract infections worldwide. We conducted a comparative analysis of the age distribution and spatiotemporal epidemiology of influenza and RSV in Russia using sentinel surveillance data from 2013-14 to 2018-19 in six cities located in the western, central, and eastern regions of the country.

Methods

We calculated the positivity rate for influenza and RSV (by month, season, and overall) in each city, separately for patients seen at the primary and secondary care level (out-patients medical centres housing GP practices and infectious diseases hospitals, respectively). We compared the age distribution of patients infected with the different influenza virus (sub)types and RSV.

Results

A total of 17 551 respiratory specimens were included: the overall positivity rate was 13.5% for influenza and 4.4% for RSV. The A(H1N1)pdm09, A(H3N2) and B virus (sub)types caused 31.3%, 44.0% and, respectively, 24.7% of all influenza cases. The median age was older among influenza (15 years) than among RSV patients (3 years); differences across influenza virus (sub)types were seen only at the primary care level, with influenza A(H3N2) patients being significantly older than A(H1N1)pdm09 or B influenza patients. The timing of influenza epidemics was similar across cities, with the peak typically occurring in February or March. In contrast, the typical peak timing of RSV epidemics varied largely across cities, and the virus was often detected also in spring and summer months (unlike influenza).

Conclusions

Influenza and RSV epidemiology differed in many regards in Russia, especially in the timing of epidemics and the age distribution of infected subjects. Health policies aimed at containing the burden of diseases of viral respiratory infections in Russia should take these findings into account.

Use of Artificial Intelligence to Triage Patients with Flu-Like Symptoms Using Imaging in Non-COVID-19 Hospitals during COVID-19 Pandemic: An Ongoing 8-Month Experience

Background  Evaluation of suspected coronavirus disease-2019 (COVID-19) patient is a diagnostic dilemma as it commonly presents like influenza in early stages. Studies and guidelines have emerged both for and against the use of imaging as a frontline tool to investigate such patients. Reverse transcriptase-polymerase chain reaction (RT-PCR) is suggested as the backbone of diagnosis. We designed and tested a diagnostic algorithm using artificial intelligence (AI) to determine the role of imaging in the evaluation of patients with acute flu-like presentation.

Materials and Methods  Overall, 3,235 consecutive patients with flu-like presentation were evaluated over a period of 240 days. All patients underwent plain radiographs of chest with computer-aided detection for COVID-19 (CAD4COVID) AI analysis. Based on the threshold scores, they were divided into two groups: group A (score < 50) and group B (score > 50). Group A patients were discharged and put on routine symptomatic treatment and follow-up with RT-PCR, while group B patients underwent high-resolution computed tomography (HRCT) followed by COVID-19 AI analysis and RT-PCR test. These were then triaged into COVID-19 and non-COVID-19 subgroups based on COVID-19 similarity scores by AI, and lung severity scores were also determined.

Results  Group A had 2,209 (68.3%) patients with CAD4COVID score of <50 while 1,026 (31.7%) patients comprised group B. Also, 825 (25.5%) patients were COVID-19 positive with COVID-19 similarity threshold of >0.85 on AI. RT-PCR was positive in 415 and false-negative in 115 patients while 12 patients died before the test could be done. The sensitivity and specificity of CAD4COVID AI analysis on plain radiographs for detection of any lung abnormality combined with HRCT AI analysis was 97.9% and 99% using the above algorithm.

Conclusion  Combined use of chest radiographs and plain HRCT with AI-based analysis is useful and an accurate frontline tool to triage patients with acute flu-like symptoms in non-COVID-19 health care facilities.

Plausibility of a third wave of COVID-19 in India: A mathematical modelling based analysis

BACKGROUND & OBJECTIVES

In the context of India's ongoing resurgence of COVID-19 (second wave since mid-February 2021, following the subsiding of the first wave in September 2020), there has been increasing speculation on the possibility of a future third wave of infection, posing a burden on the healthcare system. Using simple mathematical models of the transmission dynamics of SARS-CoV-2, this study examined the conditions under which a serious third wave could occur.

METHODS

Using a deterministic, compartmental model of SARS-CoV-2 transmission, four potential mechanisms for a third wave were examined: (i) waning immunity restores previously exposed individuals to a susceptible state, (ii) emergence of a new viral variant that is capable of escaping immunity to previously circulating strains, (iii) emergence of a new viral variant that is more transmissible than the previously circulating strains, and (iv) release of current lockdowns affording fresh opportunities for transmission.

RESULTS

Immune-mediated mechanisms (waning immunity, or viral evolution for immune escape) are unlikely to drive a severe third wave if acting on their own, unless such mechanisms lead to a complete loss of protection among those previously exposed. Likewise, a new, more transmissible variant would have to exceed a high threshold (R0>4.5) to cause a third wave on its own. However, plausible mechanisms for a third wave include: (i) a new variant that is more transmissible and at the same time capable of escaping prior immunity, and (ii) lockdowns that are highly effective in limiting transmission and subsequently released. In both cases, any third wave seems unlikely to be as severe as the second wave. Rapid scale-up of vaccination efforts could play an important role in mitigating these and future waves of the disease.

INTERPRETATION & CONCLUSIONS

This study demonstrates plausible mechanisms by which a substantial third wave could occur, while also illustrating that it is unlikely for any such resurgence to be as large as the second wave. Model projections are, however, subject to several uncertainties, and it remains important to scale up vaccination coverage to mitigate against any eventuality. Preparedness planning for any potential future wave will benefit by drawing upon the projected numbers based on the present modelling exercise.

Cohort profile: Indian Network of Population-Based Surveillance Platforms for Influenza and Other Respiratory Viruses among the Elderly (INSPIRE)

PURPOSE

We describe here a multicentric community-dwelling cohort of older adults (>60 years of age) established to estimate incidence, study risk factors, healthcare utilisation and economic burden associated with influenza and respiratory syncytial virus (RSV) in India.

PARTICIPANTS

The four sites of this cohort are in northern (Ballabgarh), southern (Chennai), eastern (Kolkata) and western (Pune) parts of India. We enrolled 5336 participants across 4220 households and began surveillance in July 2018 for viral respiratory infections with additional participants enrolled annually. Trained field workers collected data about individual-level and household-level risk factors at enrolment and quarterly assessed frailty and grip strength. Trained nurses surveilled weekly to identify acute respiratory infections (ARI) and clinically assessed individuals to diagnose acute lower respiratory infection (ALRI) as per protocol. Nasal and oropharyngeal swabs are collected from all ALRI cases and one-fifth of the other ARI cases for laboratory testing. Cost data of the episode are collected using the WHO approach for estimating the economic burden of seasonal influenza. Handheld tablets with Open Data Kit platform were used for data collection.

FINDINGS TO DATE

The attrition of 352 participants due to migration and deaths was offset by enrolling 680 new entrants in the second year. All four sites reported negligible influenza vaccination uptake (0.1%-0.4%), low health insurance coverage (0.4%-22%) and high tobacco use (19%-52%). Ballabgarh had the highest proportion (54.4%) of households in the richest wealth quintile, but reported high solid fuel use (92%). Frailty levels were highest in Kolkata (11.3%) and lowest in Pune (6.8%). The Chennai cohort had highest self-reported morbidity (90.1%).

FUTURE PLANS

The findings of this cohort will be used to inform prioritisation of strategies for influenza and RSV control for older adults in India. We also plan to conduct epidemiological studies of SARS-CoV-2 using this platform.

An Eight-Year Profile of Children with Influenza A(H1N1) in a Large Hospital in India

As influenza virus A(H1N1) continues to circulate, reports from India have documented mainly respiratory involvement in children. This retrospective chart review of children at a medical college found that from August 2009 to July 2017, 855 children aged 3 months to 15 years had H1N1 influenza of whom 310 (36.3%) were admitted and 29 (9.4% admissions) died. In 2009-12, 76.5% patients presented in August-October but from 2015 to 2017, 89.3% came in January-March. The proportion of under-fives increased from 54.0% in 2009-10 to 77.7% in 2015-17. Among admitted children, 82.6% were under 5 years, 96.1% had respiratory symptoms and 11% had seizures. Six children had encephalopathy of whom four died; two survivors had severe neurological sequelae. Other features included gastroenteritis, otitis media, myositis and hepatitis. Complications included shock (10.7%) and acute respiratory distress syndrome (6.1%). Evidence of bacterial/fungal infection was present in 71 (22.9%). Oxygen was required by 123 children (39.7%), high-dependency/intensive care by 47 (15.2%), 17 (5.5%) received high-flow oxygen and 29 (9.4%) required mechanical ventilation. There were no significantly increased odds of needing intensive care or of dying in children with underlying diseases or among different age groups but those with underlying central nervous system (CNS) diseases had higher odds of needing high-dependency/intensive care [odds ratio (OR) 2.35, p = 0.046]. Significantly, children with CNS symptoms had nearly seven times higher odds of needing mechanical ventilation (OR 6.85, p < 0.001) and over three times higher odds of dying (OR 3.31, p = 0.009). Lay summaryH1N1 Influenza ("swine flu") emerged as a global pandemic in 2009 and continues to affect children all over the world. This review of records from a medical college hospital in southern India found that 855 children aged 3 months to 15 years came with H1N1 influenza over 8 years from August 2009 to July 2017. In 2009-12, over three-quarters of them presented in the rainy season but from 2015-17, almost 90% came in the winter and spring, suggesting a change in the seasonality of the outbreaks, which could impact the choice of dates for annual influenza vaccination. The proportion under 5 years of age increased from 54% in 2009-10 to 78% in 2015-17, suggesting possible immunity in children exposed to earlier outbreaks. Over a third of the children needed admission of whom almost 40% needed oxygen, one-sixth needed high-dependency/intensive care and 1 in 11 admitted children died, emphasizing the severity of this disease. While most children had respiratory symptoms, all organs of the body were affected; 11% of those admitted had seizures and 6 had encephalitis. Children admitted with central nervous system symptoms had an almost 7-fold higher risk of needing high-dependency/intensive care and an over 3-fold higher risk of dying.

Respiratory viruses associated with severe mechanically ventilated pneumonia in children

The burden of pneumonia, especially that caused by respiratory viruses, is markedly high in the pediatric age group. This study aimed to assess viral agents causing severe pneumonia among mechanically ventilated patients. Nonbronchoscopic bronchoalveolar lavage was performed for pediatric patients having severe pneumonia indicated for mechanical ventilation to be tested with a multiplex PCR immediate diagnosis of their etiologic pathogen. Among the 75 patients recruited, viral agents were detected in 73.4% of cases. Rhinovirus and respiratory syncytial virus (RSV) were the most common viruses detected in 32.1% and 29.5%, respectively. The rate of viral infection showed a clear increased incidence in the winter season. The mortality rate among viral‐associated severe pneumonia reached 56.36%. Odds of mortality increased threefolds in presence of comorbid conditions and 10‐folds with congenital heart disease. The study demonstrated the neglected importance of rhinovirus besides RSV in causing severe critical pneumonia in the pediatric age.

Immunogenicity and safety of two quadrivalent influenza vaccines in healthy adult and elderly participants in India - A phase III, active-controlled, randomized clinical study

Background: This study was conducted to compare the immunogenicity and safety profile of two quadrivalent influenza vaccines (QIVs) in healthy adults (18-60 years) and elderly (>61 years) participants.Method: This phase III study was conducted from March 2018 to April 2018 across 12 sites in India. In this randomized, observer-blind, active-controlled study, 480 participants were randomized to receive a single dose of test vaccine (subunit, inactivated influenza vaccine; Influvac® Tetra, Abbott) (n = 240) or reference vaccine (split virion, inactivated influenza vaccine; VaxiFlu-4, Zydus Cadilla Healthcare) (n = 240). The primary objective was to describe and compare the immunogenicity of each vaccination group based on hemagglutination inhibition (HI) assay seroprotection and seroconversion rates, and geometric mean fold increase (GMFI) against four vaccine strains in two age groups. Safety and reactogenicity were also compared for the vaccines in both the age groups.Results: The pre- and post-vaccination HI titers for both the vaccines were comparable. The GMFI varied from 4.3 - 22.7 in the test and 3.7-21.6 in the reference vaccine group. The seroprotection rates were >90% for the A-strains and ranged between >43% and <60% for B-strains for both the vaccines. Seroconversion rates varied between 41.4% and 78.8%. Overall, the reported adverse events (AEs) for both the vaccines were <1% and comparable. Reported local and systemic reactions were comparable.Conclusion: Influvac® Tetra elicited an adequate immune response with a favorable safety profile which was comparable with the reference vaccine. (Clinical trial registry number: CTRI/2018/02/012222).

Efficacy of live attenuated and inactivated influenza vaccines among children in rural India: A 2-year, randomized, triple-blind, placebo-controlled trial

BACKGROUND

Influenza is a cause of febrile acute respiratory infection (FARI) in India; however, few influenza vaccine trials have been conducted in India. We assessed absolute and relative efficacy of live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) among children aged 2 to 10 years in rural India through a randomized, triple-blind, placebo-controlled trial conducted over 2 years.

METHODS AND FINDINGS

In June 2015, children were randomly allocated to LAIV, IIV, intranasal placebo, or inactivated polio vaccine (IPV) in a 2:2:1:1 ratio. In June 2016, vaccination was repeated per original allocation. Overall, 3,041 children received LAIV (n = 1,015), IIV (n = 1,010), nasal placebo (n = 507), or IPV (n = 509). Mean age of children was 6.5 years with 20% aged 9 to 10 years. Through weekly home visits, nasal and throat swabs were collected from children with FARI and tested for influenza virus by polymerase chain reaction. The primary outcome was laboratory-confirmed influenza-associated FARI; vaccine efficacy (VE) was calculated using modified intention-to-treat (mITT) analysis by Cox proportional hazards model (PH) for each year. In Year 1, VE was 40.0% (95% confidence interval (CI) 25.2 to 51.9) for LAIV and 59.0% (95% CI 47.8 to 67.9) for IIV compared with controls; relative efficacy of LAIV compared with IIV was -46.2% (95% CI -88.9 to -13.1). In Year 2, VE was 51.9% (95% CI 42.0 to 60.1) for LAIV and 49.9% (95% CI 39.2 to 58.7) for IIV; relative efficacy of LAIV compared with IIV was 4.2% (95% CI -19.9 to 23.5). No serious adverse vaccine-attributable events were reported. Study limitations include differing dosage requirements for children between nasal and injectable vaccines (single dose of LAIV versus 2 doses of IIV) in Year 1 and the fact that immunogenicity studies were not conducted.

CONCLUSIONS

In this study, we found that LAIV and IIV vaccines were safe and moderately efficacious against influenza virus infection among Indian children.

TRIAL REGISTRATION

Clinical Trials Registry of India CTRI/2015/06/005902.

Implications of monsoon season and UVB radiation for COVID-19 in India

India has recorded 142,186 deaths over 36 administrative regions placing India third in the world after the US and Brazil for COVID-19 deaths as of 12 December 2020. Studies indicate that south-west monsoon season plays a role in the dynamics of contagious diseases, which tend to peak post-monsoon season. Recent studies show that vitamin D and its primary source Ultraviolet-B (UVB) radiation may play a protective role in mitigating COVID-19 deaths. However, the combined roles of the monsoon season and UVB radiation in COVID-19 in India remain still unclear. In this observational study, we empirically study the respective roles of monsoon season and UVB radiation, whilst further exploring, whether the monsoon season negatively impacts the protective role of UVB radiation in COVID-19 deaths in India. We use a log-linear Mundlak model to a panel dataset of 36 administrative regions in India from 14 March 2020–19 November 2020 (n = 6751). We use the cumulative COVID-19 deaths as the dependent variable. We isolate the association of monsoon season and UVB radiation as measured by Ultraviolet Index (UVI) from other confounding time-constant and time-varying region-specific factors. After controlling for various confounding factors, we observe that a unit increase in UVI and the monsoon season are separately associated with 1.2 percentage points and 7.5 percentage points decline in growth rates of COVID-19 deaths in the long run. These associations translate into substantial relative changes. For example, a permanent unit increase of UVI is associated with a decrease of growth rates of COVID-19 deaths by 33% (= − 1.2 percentage points) However, the monsoon season, mitigates the protective role of UVI by 77% (0.92 percentage points). Our results indicate a protective role of UVB radiation in mitigating COVID-19 deaths in India. Furthermore, we find evidence that the monsoon season is associated with a significant reduction in the protective role of UVB radiation. Our study outlines the roles of the monsoon season and UVB radiation in COVID-19 in India and supports health-related policy decision making in India.

Maternal and Perinatal Outcomes of Influenza in Pregnancy after Treatment with Oseltamivir

Context:

Influenza infection in pregnancy causes 4%–8% case fatality and five times more perinatal mortality. Influenza is a major contributor to mortality in developing countries; however, the morbidity has largely been underestimated. Public health interventions for prevention are also lacking.

Aims:

This study aimed to determine the seasonality of influenza in pregnant Indian women and to estimate the maternal and perinatal morbidity after treatment with oseltamivir.

Settings and Design:

This was a prospective observational cohort study, conducted in a tertiary hospital.

Subjects and Methods:

Pregnant women with ILI (influenza-like illness) were recruited into Cohort 1 (polymerase chain reaction [PCR] positive) and Cohort 2 (PCR negative). Gestational age-matched asymptomatic controls formed Cohort 3. Women in Cohort 1 received oseltamivir for 5 days. The incidence of small-for-gestational age (SGA) and preterm birth were the primary outcomes. Maternal and neonatal morbidity formed the secondary outcomes.

Statistical Analysis:

Unmatched (Cohort 1 and 2) and matched analysis (Cohort 1 and 3) were done. Student's t-test and Chi-square test were used to compare between variables.

Results:

Year-round incidence of influenza was recorded. Severe illness was more in Cohort 1 compared to Cohort 2 (36.2% vs. 6.3%; P < 0.001). SGA was comparable in all the cohorts (13%). Preterm birth (7.8% vs. 3.3%; P < 0.08; relative risk-2.75) was considerably high in Cohort 1. Secondary maternal and neonatal outcomes were similar between the groups.

Conclusion:

Influenza in pregnancy showed year-round incidence and increased maternal and neonatal morbidity despite treatment with oseltamivir. We suggest the need for newer interventions to curtail the illness in pregnancy.

The Viral Etiologies of Severe Acute Respiratory Infection: Indian Perspective on the Emerging Pathogens

Severe Acute Respiratory Infection poses a significant threat to human health being a major cause of morbidity and mortality. India has witnessed several outbreaks of different infectious etiologies in the past. Among these, several new viral infections have been classified as emerging threat to humans. The word emerging refers to infectious etiologies that have newly appeared in the community or are rapidly increasing their range, corresponding to upsurge in the number of cases. Several different elements can contribute to the emergence of a new virus disease that may cause epidemic or pandemic around the globe. Containment of these viruses is difficult as most of them are of zoonotic origin. There is no immunity in the community against these viruses leaving individuals vulnerable to the disease. Factors such as socio-cultural, ecological along with human animal interphase creates challenges with respect to the emergence of these viral diseases. The major emerging viral infections of public health importance with respect to severe acute respiratory infection in India has been reviewed in this article.

Burden of influenza-associated respiratory and circulatory mortality in India, 2010-2013

Background

Influenza causes substantial morbidity and mortality worldwide, however, reliable burden estimates from developing countries are limited, including India. We aimed to quantify influenza-associated mortality for India utilizing 2010-2013 nationally representative data sources for influenza virus circulation and deaths.

Methods

Virological data were obtained from the influenza surveillance network of 10 laboratories led by National Institute of Virology, Pune covering eight states from 2010-2013. Death data were obtained from the nationally representative Sample Registration System for the same time period. Generalized linear regression with negative binomial distribution was used to model weekly respiratory and circulatory deaths by age group and proportion of specimens positive for influenza by subtype; excess deaths above the seasonal baseline were taken as an estimate of influenza-associated mortality counts and rates. Annual excess death rates and the 2011 India Census data were used to estimate national influenza-associated deaths.

Results

Estimated annual influenza-associated respiratory mortality rates were highest for those ≥65 years (51.1, 95% confidence interval (CI) = 9.2-93.0 deaths/100 000 population) followed by those <5 years (9.8, 95% CI = 0-21.8/100 000). Influenza-associated circulatory death rates were also higher among those ≥65 years (71.8, 95% CI = 7.9-135.8/100 000) as compared to those aged <65 years (1.9, 95% CI = 0-4.6/100 000). Across all age groups, a mean of 127 092 (95% CI = 64 046-190,139) annual influenza-associated respiratory and circulatory deaths may occur in India.

Conclusions

Estimated influenza-associated mortality in India was high among children <5 years and adults ≥65 years. These estimates may inform strategies for influenza prevention and control in India, such as possible vaccine introduction.

Influenza

Influenza continues to baffle humans by its constantly changing nature. The twenty-first century has witnessed considerable advances in the understanding of the influenza viral pathogenesis, its synergy with bacterial infections and diagnostic methods. However, challenges continue: to find a less expensive and more reliable point-of-care test for use in developing countries, to produce more efficacious antiviral drugs, to explore ways to combat emerging antiviral resistance and to develop vaccines that can either be produced in a shorter production time or can overcome the need for annual matching with the circulating influenza strains. Most importantly for India, as a nation that suffered the highest mortality in the influenza pandemic 1918, there is an urgent need to gear up our existing preparedness for the next pandemic which is capable to hit at any moment in time.

Seasonal incidence of respiratory viral infections in Telangana, India: utility of a multiplex PCR assay to bridge the knowledge gap

OBJECTIVE

The diagnosis of acute viral respiratory tract infections (RTI) is a challenge due to overlapping clinical presentations and lack of availability of robust diagnostic methods. This in turn leads to lack of data regarding incidence and seasonality of viral RTIs which could potentially help to implement efficient strategies of antimicrobial stewardship as well as vaccine administration. Here we utilise a commercial Multiplex PCR assay for the early diagnosis of acute respiratory tract infections and discuss their epidemiology.

METHODS

A prospective, observational study was conducted over a period of 3 years (2017-2019). Respiratory samples received from outpatients and inpatients with suspected acute RTIs from three multispeciality hospitals located in the twin cities of Hyderabad-Secunderabad were subjected to FilmArray Respiratory Panel (RP) (BioFire Diagnostics, Salt Lake City, Utah, USA). Results were tabulated and statistically analysed.

RESULTS

Of 513 samples, 261 (50.9%) were positive for one or more pathogens. The viruses detected included influenza A H1 2009 (26.0%), human rhinovirus/enterovirus (21.5%), influenza A H3N2 (17.0%), human metapneumovirus (9.4%), influenza B (6.6%), coronavirus (4.9%), parainfluenza virus (4.5%), respiratory syncytial virus (3.1%) and adenovirus (2.1%). The largest number of samples was positive during the monsoon season (43.8%). Influenza A H1 2009 peaked in the monsoon season with another, smaller peak in February.

CONCLUSIONS

There is a bimodal peak of respiratory infections relative to the seasons, and vaccine administration should take place in April-May before the advent of the monsoons in this part of the country. Multiplexed PCR may be used as first line for diagnosis of viral infections so that infection control measures can be prioritised and antibiotic administration can be avoided in those who do not require it.

Epidemic and pandemic viral infections: impact on tuberculosis and the lung: A consensus by the World Association for Infectious Diseases and Immunological Disorders (WAidid), Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases Study Group for Mycobacterial Infections (ESGMYC)

Major epidemics, including some that qualify as pandemics, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), HIV, influenza A (H1N1)pdm/09 and most recently COVID-19, affect the lung. Tuberculosis (TB) remains the top infectious disease killer, but apart from syndemic TB/HIV little is known regarding the interaction of viral epidemics and pandemics with TB. The aim of this consensus-based document is to describe the effects of viral infections resulting in epidemics and pandemics that affect the lung (MERS, SARS, HIV, influenza A (H1N1)pdm/09 and COVID-19) and their interactions with TB. A search of the scientific literature was performed. A writing committee of international experts including the European Centre for Disease Prevention and Control Public Health Emergency (ECDC PHE) team, the World Association for Infectious Diseases and Immunological Disorders (WAidid), the Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Mycobacterial Infections (ESGMYC) was established. Consensus was achieved after multiple rounds of revisions between the writing committee and a larger expert group. A Delphi process involving the core group of authors (excluding the ECDC PHE team) identified the areas requiring review/consensus, followed by a second round to refine the definitive consensus elements. The epidemiology and immunology of these viral infections and their interactions with TB are discussed with implications for diagnosis, treatment and prevention of airborne infections (infection control, viral containment and workplace safety). This consensus document represents a rapid and comprehensive summary on what is known on the topic.

Dynamic Propagation and Impact of Pandemic Influenza A (2009 H1N1) in Children: A Detailed Review

Influenza is a highly contagious respiratory infection caused by the circulating Swine flu virus. According to the World Health Organization (WHO), the unique blending strain of influenza A H1N1 2009 (Swine Flu) is a pandemic affecting several geographical regions, including India. Previous literature indicates that children are "drivers" of influenza pandemics. At present, satisfactory data were not available to accurately estimate the role of children in the spread of influenza (in particular 2009 pandemic influenza). However, the role of children in the spread of pandemics influenza is unclear. Several studies in children have indicated that the immunization program decreased the occurrence of influenza, emphasizing the significance of communities impacted by global immunization programs. This article provides a brief overview on how children are a key contributor to pandemic Influenza A (2009 H1N1) and we would like to draw your attention to the need for a new vaccine for children to improve disease prevention and a positive impact on the community.

Management of interstitial lung diseases: A consensus statement of the Indian Chest Society (ICS) and National College of Chest Physicians (NCCP)

BACKGROUND

Interstitial lung disease (ILD) is a complex and heterogeneous group of acute and chronic lung diseases of several known and unknown causes. While clinical practice guidelines (CPG) for idiopathic pulmonary fibrosis (IPF) have been recently updated, CPG for ILD other than IPF are needed.

METHODS

A working group of multidisciplinary clinicians familiar with clinical management of ILD (pulmonologists, radiologist, pathologist, and rheumatologist) and three epidemiologists selected by the leaderships of Indian Chest Society and National College of Chest Physicians, India, posed questions to address the clinically relevant situation. A systematic search was performed on PubMed, Embase, and Cochrane databases. A modified GRADE approach was used to grade the evidence. The working group discussed the evidence and reached a consensus of opinions for each question following face-to-face discussions.

RESULTS

Statements have been made for each specific question and the grade of evidence has been provided after performing a systematic review of literature. For most of the questions addressed, the available evidence was insufficient and of low to very low quality. The consensus of the opinions of the working group has been presented as statements for the questions and not as an evidence-based CPG for the management of ILD.

CONCLUSION

This document provides the guidelines made by consensus of opinions among experts following discussion of systematic review of evidence pertaining to the specific questions for management of ILD other than IPF. It is hoped that this document will help the clinician understand the accumulated evidence and help better management of idiopathic and nonidiopathic interstitial pneumonias.

Epidemiology and phylogenetic analysis of respiratory viruses from 2012 to 2015 - A sentinel surveillance report from union territory of Puducherry, India

Background

Acute respiratory infections (ARI) are the most common illnesses affecting people of all ages worldwide. Viruses contribute to 30–70% of acute respiratory infections. Identification of these respiratory viruses is not given high priority except influenza; however, the knowledge about prevalence of non-influenza viruses, their seasonal pattern and genetic evolution have significant epidemiological value.

Methods

As a part of National Influenza-like illness surveillance programme, respiratory specimens were collected children and adults with symptoms of ILI or ARI, between January 2012 and March 2015 (including SARI cases). Real-time PCR was done to identify 13 respiratory viruses. Sequencing was done for representative isolates of each virus using ABI 3730 Genetic Analyzer.

Results

During the study period between January 2012 and March 2015, a total of 648 patients with symptoms of ARI were included in this study. The mean age of the patients was 20.2 years (SD = 19.13, median = 18); 292 (45.1%) were children (≤13 years) and 356 (54.9%) were adults. Respiratory viruses were identified in 44% (287/648) of all patients. Influenza accounted for the maximum number of cases- 179/648 (27.6%). Among the non-influenza viruses, RSV predominated with 34 cases (5.2%), followed by HMPV 24 (3.7%) and PIV-3 20 (3%). Four patients died due to INF A/H1N1 (2012-2, 2015-2) as a result of acute respiratory distress syndrome (ARDS) (CFR 3.7%). Among the non-influenza viruses, no particular seasonality pattern was observed over the different months of the study period.

Conclusion

Antibiotic usage in treating acute respiratory infections empirically is not justified as nearly half of ARI are due to viruses; nearly 28% of them were due to influenza viruses. Among the non-influenza viruses, RSV predominated, followed by HMPV. This study is based on an active influenza surveillance initiated after 2009 pandemic influenza outbreak, in the Union territory of Puducherry which has contributed significantly to the knowledge of the burden of influenza and non-influenza viruses among children and adults. Such surveillance network has paved the way for better diagnosis and timely therapeutic interventions.

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First data on the epidemiology of respiratory viruses from this region after 1974.

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First study to report corona virus, HCoV OC43 from India, and only the second Indian study to document corona virus, HCoV229E. This study is the first study to analyse the genetic sequence of HCoV-229E and OC-43.

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Influenza accounted for the maximum number of cases in the study population, 27%; four patients died of Acute respiratory distress syndrome (ARDS) due to influenza A/H1N1; CFR- 3.7%.

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Among the non-influenza viruses, RSV pre-dominated followed HMPV and PIV-3. No deaths were reported due to non-influenza viral ARI. RSV was detected almost equally in adults and children.

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Distinct pattern was observed in seasonality of influenza viruses but not for non-influenza viruses.

Complete Genome Analysis of Influenza A(H1N1) Viruses Isolated in Kerala, India

Here, we report the complete sequence of four influenza A(H1N1) virus samples isolated from cases that occurred during the 2017 epidemic season in Kerala in South India. Sequence analysis showed mutations that differentiate this strain from the reference strain A/California/07/2009 virus.

Molecular characterization of Influenza A pandemic H1N1 viruses circulating in eastern India during 2017-19: Antigenic diversity in comparison to the vaccine strains

In the endemic settings of India, high CFR (3.6-7.02%) was observed in the consecutive 2009, 2015 and 2017 A/H1N1pdm09 outbreaks, though in eastern India CFR varied between 0 and 5.5% during same period. Recurrent outbreaks of pandemic Influenza A/H1N1pdm09, fragmented nationwide incidence data, lack of national policy for Influenza vaccination in India underscores the necessity for generating regional level data. Thus, during 2017-19, 4106 referred samples from patients hospitalized with severe acute respiratory illness (SARI) in eastern India were tested for A/H1N1pdm09 infection. Among which 16.5% (n = 677/4106) were found A/H1N1pdm09 positive. Individuals <20 years and middle-aged persons (40-60 years) were most susceptible to A/H1N1pdm09 infection. The vaccine strain (A/human/California/07/2009) which was globally used before 2017, clustered in a different lineage away from the representative eastern Indian strains in the phylogenetic dendrogram. The vaccine strain (A/human/Michigan/45/2015) used in India during the study period and the WHO recommended strain (A/human/Brisbane/02/2018) for 2019-20 flu season for the northern hemisphere, clustered with the circulating isolates in the same lineage-6b. Dissimilarities in the amino acids encompassing the antigenic epitopes were seen to be highest with the vaccine strain- A/human/California/07/2009. The significant amino acid variations in the circulating strains with the current WHO recommended vaccine strain, implies the exigency of continuous pandemic A/H1N1pdm09 surveillance studies in this epidemiological setting. The absence of any Oseltamivir resistant mutation (H275Y) in the neuraminidase gene of the current isolates suggests continuing use of Tamiflu® as an antiviral therapy in suspected subjects in this region.

Molecular characterization of influenza A(H1N1)pdm09 viruses circulating at various geographical locations in India, 2017

Background & objectives

Influenza virological surveillance is an essential tool for the early detection of novel genetic variants of epidemiologic and clinical significance. This study was aimed to genetically characterize A(H1N1)pdm09 virus circulating in 2017 and to compare it with the global data.

Methods

The regional/State Viral Research and Diagnostic Laboratories (VRDLs) provided influenza diagnosis for referred clinical samples and shared influenza A(H1N1)pdm09 positives with the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Pune, India, for hemagglutinin (HA) gene phylogenetic analysis. Sites at Manipal, Jaipur and Dibrugarh performed the sequencing and shared the sequence data for analysis. The antiviral susceptibility of influenza viruses was assessed for known molecular marker H275Y at the ICMR-NIV, Pune.

Results

All the eight VRDLs had well-established influenza diagnostic facilities and showed increased activity of influenza A(H1N1)pdm09 during 2017. Phylogenetic analysis showed that the viruses from the different regions of the country were similar to A/Michigan/45/2015 strain which was the 2017-2018 recommended vaccine strain and were clustered with the globally circulating clade 6B.1 with signature mutations S84N, S162N and I216T. The clade 6B.1 showed further subgrouping with additional mutations S74R, S164T and I295V; however, there was no significant association between the presence of these mutations and severity of disease due to influenza. All the study viruses were sensitive to oseltamivir.

Interpretation & conclusions

During the study period, all the study sites reported globally circulating A/Michigan/45/2015 vaccine strain of influenza A(H1N1)pdm09 viruses and remained sensitive to oseltamivir. Further genetic and antigenic characterization of influenza viruses is recommended to address public health concerns.

Influenza in temperate and tropical Asia: a review of epidemiology and vaccinology

The impact of seasonal influenza has been under-appreciated in Asia and surveillance data lags in most other regions. The variety of influenza circulation patterns in Asia – largely due to the range of climates – has also only recently been recognized and its effect on the burden of disease is not fully understood. Recent reports that clinical protection wanes in the weeks after influenza vaccination emphasize the importance of optimally timing vaccination to local epidemiology. It also raises questions as to whether influenza vaccines should be administered more frequently than annually and what may be the benefits in Asia of access to new vaccines with enhanced immunogenicity and effectiveness. This review will summarize influenza surveillance data from Asian countries over 2011–2018, and consider the implications for vaccination strategies in different parts of Asia.

Clinical practice guidelines 2019: Indian consensus-based recommendations on influenza vaccination in adults

Influenza, a common cause of acute respiratory infections, is an important health problem worldwide, including in India. Influenza is associated with several complications; people with comorbidities and the elderly are at a higher risk for such complications. Moreover, the influenza virus constantly changes genetically, thereby worsening therapeutic outcomes. Vaccination is an effective measure for the prevention of influenza. Despite the availability of global guidelines on influenza vaccination in adults, country-specific guidelines based on regional variation in disease burden are required for better disease management in India. With this aim, the Indian Chest Society and National College of Chest Physicians of India jointly conducted an expert meeting in January 2019. The discussion was aimed at delineating evidence-based recommendations on adult influenza vaccination in India. The present article discusses expert recommendations on clinical practice guidelines to be followed in India for adult influenza vaccination, for better management of the disease burden.

Hotspots of H1N1 influenza in India: analysis of reported cases and deaths (2010-2017)

Influenza A (H1N1) caused significant mortality and morbidity globally. We identified the hotspots for H1N1 influenza in India using cases and deaths reported in the Integrated Disease Surveillance Program between 2010 and 2017. A total of 114,667 cases and 8543 deaths were reported from across India, at an overall case fatality rate of 7.5%. While Maharashtra accounted for 21% of cases and 31% of deaths, Delhi and Gujarat were ranked the highest based on the population-adjusted ranks for morbidity and mortality, respectively. The current analysis identified states and union territories in western India (Delhi, Punjab, Rajasthan, Gujarat and Maharashtra) to be especially vulnerable.

Seasonal variation and etiologic inferences of childhood pneumonia and diarrhea mortality in India

Control of pneumonia and diarrhea mortality in India requires understanding of their etiologies. We combined time series analysis of seasonality, climate region, and clinical syndromes from 243,000 verbal autopsies in the nationally representative Million Death Study. Pneumonia mortality at 1 month-14 years was greatest in January (Rate ratio (RR) 1.66, 99% CI 1.51-1.82; versus the April minimum). Higher RRs at 1-11 months suggested respiratory syncytial virus (RSV) etiology. India's humid subtropical region experienced a unique summer pneumonia mortality. Diarrhea mortality peaked in July (RR 1.66, 1.48-1.85) and January (RR 1.37, 1.23-1.48), while deaths with fever and bloody diarrhea (indicating enteroinvasive bacterial etiology) showed little seasonality. Combining mortality at ages 1-59 months with prevalence surveys, we estimate 40,600 pneumonia deaths from Streptococcus pneumoniae, 20,700 from RSV, 12,600 from influenza, and 7200 from Haemophilus influenzae type b and 24,700 diarrheal deaths from rotavirus occurred in 2015. Careful mortality studies can elucidate etiologies and inform vaccine introduction.