Social Distancing, Lockdown and the Wide Use of Mask; A Magic Solution or a Double-Edged Sword for Respiratory Viruses Epidemiology?

Increase of Synergistic Secondary Antiviral Mutations in the Evolution of A(H1N1)pdm09 Influenza Virus Neuraminidases

The unexpected emergence of oseltamivir-resistant A(H1N1) viruses in 2008 was facilitated in part by the establishment of permissive secondary neuraminidase (NA) substitutions that compensated for the fitness loss due to the NA-H275Y resistance substitution. These viruses were replaced in 2009 by oseltamivir-susceptible A(H1N1)pdm09 influenza viruses. Genetic analysis and screening of A(H1N1)pdm09 viruses circulating in Germany between 2009 and 2024 were conducted to identify any potentially synergistic or resistance-associated NA substitutions. Selected viruses were then subjected to further characterization in vitro. In the NA gene of circulating A(H1N1)pdm09 viruses, two secondary substitutions, NA-V241I and NA-N369K, were identified. These substitutions demonstrated a stable lineage in phylogenetic analysis since the 2010-2011 influenza season. The data indicate a slight increase in viral NA bearing two additional potentially synergistic substitutions, NA-I223V and NA-S247N, in the 2023-2024 season, which both result in a slight reduction in susceptibility to NA inhibitors. The accumulation of secondary synergistic substitutions in the NA of A(H1N1)pdm09 viruses increases the probability of the emergence of antiviral-resistant viruses. Therefore, it is crucial to closely monitor the evolution of circulating influenza viruses and to develop additional antiviral drugs against different target proteins.

Microbiological and epidemiological features of respiratory syncytial virus

The properties of the main surface proteins and the viral cycle of the respiratory syncytial virus (RSV) make it an attractive pathogen from the perspective of microbiology. The virus gets its name from the manner it infects cells, which enables it to produce syncytia, which allow the virus' genetic material to move across cells without having to release viral offspring to the cellular exterior, reducing immune system identification. This causes a disease with a high impact in both children and adults over 60, which has sparked the development of several preventive interventions based on vaccines and monoclonal antibodies for both age groups. The epidemiological characteristics of this virus, which circulates in epidemics throughout the coldest months of the year and exhibits a marked genetic and antigenic drift due to its high mutation capability, must be taken into consideration while using these preventive methods. The most important microbiological and epidemiological elements of RSV are covered in this study, along with how they have affected the creation of preventive medications and their use in the future.

The impact of non-pharmaceutical interventions on community non-SARS-CoV-2 respiratory infections in preschool children

BACKGROUND

Effects of non-pharmaceutical interventions during the pandemic were mainly studied for severe outcomes. Among children, most of the burden of respiratory infections is related to infections which are not medically attended. The perspective on infections in the community setting is necessary to understand the effects of the pandemic on non-pharmaceutical interventions.

METHODS

In the unique prospective LoewenKIDS cohort study, we compared the true monthly incidence of self-reported acute respiratory infections (ARI) in about 350 participants (aged 3-4 years old) between October 2019 to March 2020 (pre-pandemic period) and October 2020 to March 2021 (pandemic period). Parents reported children's symptoms using a diary. Parents were asked to take a nasal swab of their child during all respiratory symptoms. We analysed 718 swabs using Multiplex PCR for 25 common respiratory viruses and bacteria.

RESULTS

During the pre-pandemic period, on average 44.6% (95% CI: 39.5-49.8%) of children acquired at least one ARI per month compared to 19.9% (95% CI: 11.1-28.7%) during the pandemic period (Incidence Rate Ratio = 0.47; 95% CI: 0.41-0.54). The detection of influenza virus decreased absolute by 96%, respiratory syncytial virus by 65%, metapneumovirus by 95%, parainfluenza virus by 100%, human enterovirus by 96% and human bocavirus by 70% when comparing the pre-pandemic to the pandemic period. However, rhinoviruses were nearly unaffected by NPI. Co-detection (detection of more than one virus in a single symptomatic swab) was common in the pre-pandemic period (222 of 390 samples with viral detection; 56.9%) and substantially less common during the pandemic period (46 of 216 samples; 21.3%).

CONCLUSION

Non-pharmaceutical interventions strongly reduced the incidence of all respiratory infections in preschool children but did not affect rhinovirus.

Potential Effects on Elderly People From Nirsevimab Use in Infants

Nirsevimab therapy has the potential to revolutionize infant respiratory syncytial virus (RSV) prophylaxis. But other populations suffering RSV, such the elderly or those over 60, may also be protected by using this novel antibody in the infant group. It is true that some studies link the use of nirsevimab to a reduction in the virus's ability to spread by lowering the viral load in infants as a result of the drug's long half-life. However, this protective effect may not be very significant because RSV transmission in the elderly typically comes from other elderly people or from school-aged children. Furthermore, RSV may be transmitted at any time of the year and not just during the period of nirsevimab protection due to its existence in human reservoirs. The reasons made here show that, even though nirsevimab treatment in infants may protect the elderly, this benefit would be limited and testimonial. Therefore, immunizing the elderly with currently licensed and developing vaccines should be a priority.

The influenza landscape and vaccination coverage in older adults during the SARS-Cov-2 pandemic: data from Several European Countries and Israel

INTRODUCTION

The Raise Awareness of Influenza Strategies in Europe (RAISE) group gathered information about the healthcare burden of influenza (hospitalizations, intensive care unit [ICU] admissions, and excess deaths), surveillance systems, and the vaccine coverage rate (VCR) in older adults in 18 European countries and Israel.

AREAS COVERED

Published medical literature and official medical documentation on the influenza disease burden in the participating countries were reviewed from 2010/11 until the 2022/23 influenza seasons. Information on the framework for monitoring the disease burden and the provision for ensuring older adults had access to vaccination in their respective countries was provided. Data on influenza VCR in older adults were collected for the 2019/20 to 2022/23 influenza seasons. Data are reported descriptively.

EXPERT OPINION

Influenza presents a significant healthcare burden in older adults. Reporting outcomes across participating countries is heterogeneous, highlighting the need for standardized approaches. Although older adults receive free influenza vaccination, vaccine uptake is highly variable among countries. Moreover, hospitalization rates remain high even in countries reporting a high VCR. Increased awareness and education on the burden of disease and the broader use of improved influenza vaccines for older adults may help reduce the disease burden on this population.

Investigating epidemiological distribution (temporality and intensity) of respiratory pathogens following COVID-19 de-escalation process in Catalonia, September 2016-June 2021: Analysis of regional surveillance data

BACKGROUND

Following the low incidence rates of non-SARS-CoV-2 respiratory viruses registered during the strict lockdown enforced in the pandemic, a resurgence of several endemic viruses in Catalonia (Spain) was noted during the early summer of 2021.

OBJECTIVES

In this study, we investigated whether the circulation of non-SARS-CoV-2 respiratory viruses in Catalonia, assessed by Microbiological Reporting System of Catalonia (MRSC) and the Epidemiological Surveillance Network of Catalonia, was affected by the strict lockdown measures, as well as, the implication of the Coronavirus Disease 19 (COVID-19) de-escalation process in the late season outbreaks registered during the 2020-2021 season.

STUDY DESIGN

A retrospective comparison of epidemic patterns in the respiratory viruses' incidence, using regional public health surveillance data from MRSC, was performed between weeks 26/2016 to week 27/2021. Data were expressed as the weekly total number of test positivity for individual viruses. A segmented negative binomial regression model was conducted, with two parameters included (level and trend) for each segment of the time series (2020 pre-lockdown, 2020 post-lockdown and 2021). Results were reported as a unit changed in the strict lockdown.

RESULTS

A total of 51588 confirmed cases of the different respiratory viruses were included in the analysis, the majority were influenza cases (63.7%). An immediate reduction in the weekly number of cases was observed in 2020 after the COVID-19 outbreak for human adenovirus virus (HAdV) (β2 = -2.606; P <0.01), human parainfluenza virus (HPIV) (β2 = -3.023; P <0.01), influenza virus (IFV) (β2 = -1.259; P <0.01), but not for respiratory syncytial virus (RSV), where the number of cases remained unchanged. During 2020, a significant negative trend was found for RSV (β3 = -0.170, P <0.01), and a positive trend for HAdV (β3 = 0.075, P <0.01). During 2021, a significant reduction in the weekly number of cases was also observed for all respiratory viruses, and a borderline non-significant reduction for HPIV (β3 = -0.027; P = 0.086). Moreover, significant positive trends were found for each viral pathogen, except for influenza during 2020-2021 season, where cases remained close to zero. The respiratory viruses increased activity and their late season epidemic start particularly affected children under 6 years old.

CONCLUSIONS

Our data not only provides evidence that occurrence of different respiratory virus infections was affected by the strict lockdown taken against SARS-CoV-2 but it also shows a late resurgence of seasonal respiratory viruses' cases during the 2020-2021 season following the relaxation of COVID-19-targeted non-pharmaceutical interventions.

Descriptive analysis to assess seasonal patterns of COVID-19 and influenza in low-income and middle-income countries in Asia, the Middle East and Latin America

OBJECTIVES

Understanding disease seasonality can help predict the occurrence of outbreaks and inform public health planning. Respiratory diseases typically follow seasonal patterns; however, knowledge regarding the seasonality of COVID-19 and its impact on the seasonality of influenza remains limited. The objective of this study was to provide more evidence to understand the circulation of SARS-CoV-2, the virus responsible for COVID-19, in an endemic scenario to guide potential preventive strategies.

DESIGN

In this study, a descriptive analysis was undertaken to describe seasonality trends and/or overlap between COVID-19 and influenza in 12 low-income and middle-income countries using Our World in Data and FluMart data sources. Plots of COVID-19 and influenza cases were analysed.

SETTING

Singapore, Thailand, Malaysia, the Philippines, Argentina, Brazil, Mexico, South Africa, Morocco, Bahrain, Qatar and Saudi Arabia.

OUTCOME MEASURES

COVID-19 cases and influenza cases.

RESULTS

No seasonal patterns of SARS-CoV-2 or SARS-CoV-2/influenza cocirculation were observed in most countries, even when considering the avian influenza pandemic period.

CONCLUSIONS

These results can inform public health strategies. The lack of observed seasonal behaviour highlights the importance of maintaining year-round vaccination rather than implementing seasonal campaigns. Further research investigating the influence of climate conditions, social behaviour and year-round preventive measures could be fundamental for shaping appropriate policies related to COVID-19 and respiratory viral disease control in low-income and middle-income countries as COVID-19 variant data and epidemiologic patterns accrue over time.

Old and new aspects of influenza

Influenza is a classic infectious disease that, through the continuous variation of the viruses that produce it, imposes new challenges that we must solve as quickly as possible. The COVID-19 pandemic has substantially modified the behavior of influenza and other respiratory viruses, and in the coming years we will have to coexist with a new pathogen that will probably interact with existing pathogens in a way that we cannot yet glimpse. However, knowledge prior to the pandemic allows us to focus on the aspects that must be modified to make influenza an acceptable challenge for the future. In this review, emphasis is placed on the most relevant aspects of epidemiology, disease burden, diagnosis, and vaccine prevention, and how scientific and clinical trends in these aspects flow from the previously known to future challenges.

Monitoring influenza and respiratory syncytial virus in wastewater. Beyond COVID-19

Wastewater-based surveillance can be a valuable tool to monitor viral circulation and serve as an early warning system. For respiratory viruses that share similar clinical symptoms, namely SARS-CoV-2, influenza, and respiratory syncytial virus (RSV), identification in wastewater may allow differentiation between seasonal outbreaks and COVID-19 peaks. In this study, to monitor these viruses as well as standard indicators of fecal contamination, a weekly sampling campaign was carried out for 15 months (from September 2021 to November 2022) in two wastewater treatment plants that serve the entire population of Barcelona (Spain). Samples were concentrated by the aluminum hydroxide adsorption-precipitation method and then analyzed by RNA extraction and RT-qPCR. All samples were positive for SARS-CoV-2, while the positivity rates for influenza virus and RSV were significantly lower (10.65 % for influenza A (IAV), 0.82 % for influenza B (IBV), 37.70 % for RSV-A and 34.43 % for RSV-B). Gene copy concentrations of SARS-CoV-2 were often approximately 1 to 2 logarithmic units higher compared to the other respiratory viruses. Clear peaks of IAV H3:N2 in February and March 2022 and RSV in winter 2021 were observed, which matched the chronological incidence of infections recorded in the Catalan Government clinical database. In conclusion, the data obtained from wastewater surveillance provided new information on the abundance of respiratory viruses in the Barcelona area and correlated favorably with clinical data.

Can Google Trends analysis confirm the public's need for information about the rare association of facial nerve paralysis with COVID-19 or the COVID-19 vaccination?

Facial nerve paralysis or Bell's palsy have been suggested as possible consequences of SARS-CoV-2 infections, as well as possible side effects of COVID-19 vaccinations. Google Trends data have been used to evaluate worldwide levels of public awareness for these topics for pre- and post-pandemic years. The results demonstrate a relatively low public interest in facial nerve paralysis in comparison to other more common COVID-19 related topics. Some peaks of interest in Bell's palsy can most likely be explained as triggered by the media. Therefore, Google Trends has shown public's relatively low awareness of this rare neurological phenomenon during the pandemic.

Disappearance and Re-Emergence of Influenza during the COVID-19 Pandemic: Association with Infection Control Measures

During the coronavirus disease 2019 (COVID-19) pandemic, the influenza virus had a very low prevalence, and in many areas, outbreaks were almost non-existent. In this study, the associations between infection control measures taken for COVID-19 and the global disappearance of the influenza virus were investigated. The detection rate of influenza from baseline was investigated during four seasons (12 weeks from epidemiological week 49 in 2020 and 2021 and 12 weeks from epidemiological week 23 in 2020 and 2021) in each country participating in the surveillance system of the World Health Organization. Three measures of infection control: mask use ratio, social distancing index (an index of human mobility and physical distance obligations), and an index of stringency of measures taken by authorities were studied. In mid-2020, most countries analyzed had high levels of infection control measures, and in most countries, influenza was drastically reduced compared to previous years. Multiple regression analyses compared the study data with data from other seasons. There was an association between high mask use with low influenza detection in all three remaining seasons, an association between a low social distancing index (low mobility and more social contact obligations) with a low influenza detection rate in two seasons, and a marginal significant association of high stringency index with a low influenza detection rate(in 2020-end-seasons). These results support the notion that seasonal influenza is controllable through effective preventive measures, especially those of mask use and human social contact, and these measures should be recommended during future waves of novel influenza virus infection.

Viruses responsible for acute respiratory infections before (2016-2019) and during (2021) circulation of the SARS-CoV-2 virus in pediatric patients in a reference center at Barranquilla Colombia: A pattern analysis

OBJECTIVE

To evaluate the behavior of the viruses responsible for acute respiratory infections before (2016-2019) and after (2020-2021) the start of the circulation of the SARS-CoV-2 virus in pediatric patients treated at a reference center from Barranquilla, Colombia.

MATERIALS AND METHODS

A descriptive observational study was carried out, and data were obtained by reviewing the influenza-like illness and severe acute respiratory infection database in the pediatric population of the sentinel surveillance reference center in the district of Barranquilla during the years 2016-2021, applying inclusion and exclusion criteria.

RESULTS

During 2016-2019, the average age of individuals was 1.3 (±1.7) years, during 2021, it was 2.3 (±3.5) years. The distribution by sex was similar, predominantly male. August and February were the months with the highest record of symptoms for 2016-2019 and 2021, respectively, the most frequent being cough, fever, shortness of breath, and diarrhea. By 2021 there was a higher use of antibiotics and antivirals reported than in 2016-2019. Most patients tested negative for viral detection. When comparing the percentage of viruses detected by age group and years of detection, positivity was lower in 2021 by every age group, and respiratory syncytial virus (RSV) was the most frequently detected.

CONCLUSIONS

There was less virus positivity in viral detection tests in the pediatric population in 2021. RSV persists as the main etiology affecting this population, especially infants. The use of antibiotic therapy in viral infections continues to be a problematic practice in their management. Sentinel surveillance can be strengthened throughout the country.

How the COVID 19 pandemic will shape influenza public health initiatives: The UK experience

Although caused by different pathogens, COVID-19 and influenza share many clinical features, as well as the potential for inflammatory, cardiovascular, and other long-term complications. During the 2020-2021 influenza season, COVID-19 mitigation efforts and a robust influenza vaccination campaign led to an unprecedented reduction in influenza cases. The lack of exposure to influenza, along with antigenic changes, may have reduced population immunity to influenza and set the stage for a high severity influenza season in 2021-2022. For the second consecutive season, the UK Department of Health and Social Care has expanded influenza vaccine eligibility to mitigate the impact of both COVID-19 and influenza. Continuation of clear policy decisions, as well as ongoing coordination between manufacturers, distributors, health authorities, and healthcare providers, is key to reducing the burden of influenza and COVID-19 and preventing large numbers of severe cases that can overwhelm the healthcare system.

What's Next for Flu? Out-of-Season Circulation of Influenza Viruses in Southern Italy, August 2022

The COVID-19 pandemic has modified the seasonal pattern of respiratory infections. The objective of the present study is to characterize the out-of-season circulation of influenza viruses and an influenza outbreak that occurred in southern Italy in August 2022. Nasopharyngeal swabs collected from patients with influenza-like illnesses (ILI) were tested for the presence of influenza and other respiratory viruses. Epidemiological investigations on 85 patients involved in an influenza outbreak were performed. Sequencing and phylogenetic analysis of hemagglutinin genes was undertaken on samples positive for influenza A. In August 2022, in the Apulia region (Italy), influenza A infection was diagnosed in 19 patients, 18 infected with A/H3N2 and one with A/H1N1pdm09 virus. Seven influenza-positive patients were hospitalized with ILI. A further 17 symptomatic subjects, associated with an influenza outbreak, were also tested; 11 were positive for influenza A/H3N2 virus. Phylogenetic analysis of 12 of the A/H3N2 sequences showed that they all belonged to subclade 3C.2a1b.2a.2. The A/H1N1pdm09 strain belonged to subclade 6B.1A.5a.2. The out-of-season circulation of the influenza virus during the summer months could be linked to changing dynamics in the post-COVID-19 era, as well as to the impact of climate change. Year-round surveillance of respiratory viruses is needed to monitor this phenomenon and to provide effective prevention strategies.

Impact of COVID-19 Pandemic and Lockdown on the Epidemiology of RSV-Mediated Bronchiolitis: Experience from Our Centre

Background: The COVID-19 pandemic has dramatically affected the global epidemiology of other infectious respiratory diseases, leading to a significant decrease in their incidence. Hence, we aimed to characterize the epidemiology of RSV-bronchiolitis in children. Methods: children aged ≤2 years diagnosed with RSV-mediated bronchiolitis admitted to our Unit from October 2018 to December 2021, were retrospectively enrolled. Results: We included 95 patients (M/F = 46/49; mean age 7.56 ± 6.6 months). Specifically, 17 infants in 2018, 34 in 2019, 0 during 2020 lockdown, 1 during 2020 post-lockdown, and 43 in 2021. Incidence was significantly lower in 2020 compared with 2018, 2019 and 2021 (p < 0.05). No differences were found concerning need for respiratory support. Discussion: Several factors related to SARS-CoV-2 pandemic, especially restrictive measures, may have contributed to a significant reduction in hospitalizations due to RSV. The new outbreak in RSV infection-related hospitalizations reported between October and December 2021 has been suggested it may be due to an increased number of susceptible individuals to RSV infection. Conclusion: The experience of the SARS-CoV-2 outbreak has led to a marked decrease in other viral respiratory infections, such as RSV. This may pave the way for new approaches in preventing respiratory infections, highlighting the role of preventive measures.

Age-dependent rebound in asthma exacerbations after COVID-19 lockdown

Background

Virus mitigation measures enacted early in the coronavirus infectious disease 2019 (COVID-19) pandemic suppressed common respiratory viruses and reduced the number of obstructive lung disease exacerbations. However, many localities began to ease these precautions in the year 2021, leading to a resurgence of non-COVID viruses. How asthma and chronic obstructive pulmonary disease (COPD) activity responded to this upswing in viral abundance is unclear.

Objective

Our aim was to examine how viral resurgence during the relaxation of COVID-19 restrictions affected asthma and COPD exacerbations.

Methods

We analyzed electronic medical records for emergency department (ED) respiratory virus positivity, asthma visits, and COPD visits. We compared the 52-week interval before the COVID-19 restrictions (the pre-lockdown period [March 22, 2019-March 19, 2020]), the 52-week period immediately following enactment of the restrictions (the lockdown period [March 20, 2020-March 18, 2021]), and the 52-week period thereafter (the post-lockdown period [March 19, 2021-March 18, 2022]). We used MetaCYCLE to analyze seasonal trends in our data.

Results

The post-lockdown period was marked by a 400% increase in viral positivity compared with during the lockdown period. Asthma- and COPD-related ED visits each rose 37% compared with during the lockdown, with the rebound in asthma ED visits concentrated in individuals younger than 20 years. Interestingly, after the lockdown period, asthma ED visits overcorrected in children younger than 5 years, rising 81% compared with before the lockdown. Seasonal rhythms in asthma and COPD exacerbations were suppressed during the lockdown and recovered after the lockdown.

Conclusions

COVID-19 precautions had the unexpected effect of magnifying early-childhood asthma activity once common respiratory viruses recurred. These results may have implications for the future use of virus mitigation strategies in young children.

Hepatitis of unknown aetiology in children - epidemiological overview of cases reported in Europe, 1 January to 16 June 2022

Following the report of an excess in paediatric cases of severe acute hepatitis of unknown aetiology by the United Kingdom (UK) on 5 April 2022, 427 cases were reported from 20 countries in the World Health Organization European Region to the European Surveillance System TESSy from 1 January 2022 to 16 June 2022. Here, we analysed demographic, epidemiological, clinical and microbiological data available in TESSy. Of the reported cases, 77.3% were 5 years or younger and 53.5% had a positive test for adenovirus, 10.4% had a positive RT-PCR for SARS-CoV-2 and 10.3% were coinfected with both pathogens. Cases with adenovirus infections were significantly more likely to be admitted to intensive care or high-dependency units (OR = 2.11; 95% CI: 1.18–3.74) and transplanted (OR = 3.36; 95% CI: 1.19–9.55) than cases with a negative test result for adenovirus, but this was no longer observed when looking at this association separately between the UK and other countries. Aetiological studies are needed to ascertain if adenovirus plays a role in this possible emergence of hepatitis cases in children and, if confirmed, the mechanisms that could be involved.

Influence of the COVID-19 pandemic measures on incidence and representation of other infectious diseases in Germany: a lesson to be learnt

Aim

The COVID-19 pandemic resulted in a wide range of serious health, social and economic consequences. To counteract the pandemic, various measures and restrictions such as lockdowns, closures, social distancing, hygiene, and protective measures such as wearing face masks have been enforced. Apart from the COVID-19 pandemic, these measures also had effects on other transmittable diseases. This study therefore determined the impact on case numbers and interest for other infectious diseases as well.

Subject and methods

Anonymized data on reported case numbers from the German Robert Koch Institute and data from Google Trends about the search interest have been used in this study to track courses of infectious diseases before and during the coronavirus pandemic in Germany.

Results

The results of this analysis clearly demonstrated that the case numbers of influenza, whooping cough, measles, mumps, scarlet fever and chicken pox decreased in the pandemic years, most probably due to anti-pandemic measures in Germany. Additionally, the Google Trends analysis demonstrated public awareness, documented by a corresponding search interest, for the new topic COVID-19 and for other infectious diseases.

Conclusion

Online available data provided valuable sources for research purposes in infodemiology or infoveillance.

International changes in respiratory syncytial virus (RSV) epidemiology during the COVID-19 pandemic: Association with school closures

BACKGROUND

Little RSV activity was observed during the first expected RSV season since the COVID-19 pandemic. Multiple countries later experienced out-of-season RSV resurgences, yet their association with non-pharmaceutical interventions (NPIs) is unclear. This study aimed to describe the changes in RSV epidemiology during the COVID-19 pandemic and to estimate the association between individual NPIs and the RSV resurgences.

METHODS

RSV activity from Week (W)12-2020 to W44-2021 was compared with three pre-pandemic seasons using RSV surveillance data from Brazil, Canada, Chile, France, Israel, Japan, South Africa, South Korea, Taiwan, the Netherlands and the United States. Changes in nine NPIs within 10 weeks before RSV resurgences were described. Associations between NPIs and RSV activity were assessed with linear mixed models. Adherence to NPIs was not taken into account.

RESULTS

Average delay of the first RSV season during the COVID-19 pandemic was 39 weeks (range: 13-88 weeks). Although the delay was <40 weeks in six countries, a missed RSV season was observed in Brazil, Chile, Japan, Canada and South Korea. School closures, workplace closures, and stay-at-home requirements were most commonly downgraded before an RSV resurgence. Reopening schools and lifting stay-at-home requirements were associated with increases of 1.31% (p = 0.04) and 2.27% (p = 0.06) in the deviation from expected RSV activity.

CONCLUSION

The first RSV season during the COVID-19 pandemic was delayed in the 11 countries included. Reopening of schools was consistently associated with increased RSV activity. As NPIs were often changed concomitantly, the association between RSV activity and school closures may be partly attributed to other NPIs.

An index of access to essential infrastructure to identify where physical distancing is impossible

To identify areas at highest risk of infectious disease transmission in Africa, we develop a physical distancing index (PDI) based on the share of households without access to private toilets, water, space, transportation, and communication technology and weight it with population density. Our results highlight that in addition to improving health systems, countries across Africa, especially in the western part of Africa, need to address the lack of essential domestic infrastructure. Missing infrastructure prevents societies from limiting the spread of communicable diseases by undermining the effectiveness of governmental regulations on physical distancing. We also provide high-resolution risk maps that show which regions are most limited in protecting themselves. We find considerable spatial heterogeneity of the PDI within countries and show that it is highly correlated with detected COVID-19 cases. Governments could pay specific attention to these areas to target limited resources more precisely to prevent disease transmission.

Lack of private infrastructure remains a major challenge potentially hampering a societies’ ability to contain the transmission of communicable diseases. Areas at high risk in Africa are identified based on access to essential basic infrastructure.

Recent Progress in Recombinant Influenza Vaccine Development Toward Heterosubtypic Immune Response

Flu, a viral infection caused by the influenza virus, is still a global public health concern with potential to cause seasonal epidemics and pandemics. Vaccination is considered the most effective protective strategy against the infection. However, given the high plasticity of the virus and the suboptimal immunogenicity of existing influenza vaccines, scientists are moving toward the development of universal vaccines. An important property of universal vaccines is their ability to induce heterosubtypic immunity, i.e., a wide immune response coverage toward different influenza subtypes. With the increasing number of studies and mounting evidence on the safety and efficacy of recombinant influenza vaccines (RIVs), they have been proposed as promising platforms for the development of universal vaccines. This review highlights the current progress and advances in the development of RIVs in the context of heterosubtypic immunity induction toward universal vaccine production. In particular, this review discussed existing knowledge on influenza and vaccine development, current hemagglutinin-based RIVs in the market and in the pipeline, other potential vaccine targets for RIVs (neuraminidase, matrix 1 and 2, nucleoprotein, polymerase acidic, and basic 1 and 2 antigens), and deantigenization process. This review also provided discussion points and future perspectives in looking at RIVs as potential universal vaccine candidates for influenza.

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

Introduction

A 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 in the EMR.

Objective

We aim to present data on seasonal influenza activity during the pre-pandemic period (2016–2019) and compare it to the pandemic period (2020–2021) in EM countries.

Methods

Epidemiological and virological influenza surveillance data were retrieved from both WHO FluNet and EMFLU networks. Four pre-pandemic analytical periods were used in the comparative analysis. We compiled and calculated weekly aggregated epidemiological data on the number of enrolled patients, number of tested specimens and number of positive influenza specimens.

Results

19 out of the 22 countries of the EMR have functioning sentinel influenza surveillance systems, and these countries report the influenza data to WHO through FluNet and EMFLU. The number of enrolled patients and tested specimens increased gradually from 51 384 and 50 672, respectively, in 2016–2017 analytical period to 194 049 enrolled patients and 124 697 tested specimens in 2019–2020. A decrease has been witnessed in both enrolled patients and tested specimens in 2020–2021 ‘pandemic period’ (166 576 and 44 764, respectively). By comparing influenza activity of analytical period 2020–2021 with that of 2016–2019 analytical periods, we found that there has been a decrease in influenza positivity rate in the EMR by 89%.

Conclusion

The implementation of non-pharmaceutical interventions to control the COVID-19 pandemic may have also impacted the spread of influenza viruses. The low circulation of influenza viruses during 2020–2021 and the associated potential immunity gap may result in increased transmission and severity of post-pandemic influenza seasons. This necessitates high vigilance to continuous data and virus sharing to monitor circulating viruses in a timely fashion to reduce the intensity and severity of future influenza epidemics.

New Wave of COVID-19 Vaccine Opinions in the Month the 3rd Booster Dose Arrived

Vaccination has been proposed as one of the most effective methods to combat the COVID-19 pandemic. Since the day the first vaccine, with an efficiency of more than 90%, was announced, the entire vaccination process and its possible consequences in large populations have generated a series of discussions on social media. Whereas the opinions triggered by the administration of the initial COVID-19 vaccine doses have been discussed in depth in the scientific literature, the approval of the so-called 3rd booster dose has only been analyzed in country-specific studies, primarily using questionnaires. In this context, the present paper conducts a stance analysis using a transformer-based deep learning model on a dataset containing 3,841,594 tweets in English collected between 12 July 2021 and 11 August 2021 (the month in which the 3rd dose arrived) and compares the opinions (in favor, neutral and against) with the ones extracted at the beginning of the vaccination process. In terms of COVID-19 vaccination hesitance, an analysis based on hashtags, n-grams and latent Dirichlet allocation is performed that highlights the main reasons behind the reluctance to vaccinate. The proposed approach can be useful in the context of the campaigns related to COVID-19 vaccination as it provides insights related to the public opinion and can be useful in creating communication messages to support the vaccination campaign.

The secondary outcome of public health measures amidst the COVID-19 pandemic in the spread of other respiratory infectious diseases in Thailand

The coronavirus disease 2019 (COVID-19) has promoted stringent public health measures such as hand hygiene, face mask wearing, and physical distancing to contain the spread of the viral infection. In this retrospective study, the secondary outcomes of those public health measures on containing other respiratory infections among the Thai population were investigated. Hospitalization data spanning from 2016 to 2021 of six respiratory infectious diseases, namely influenza, measles, pertussis, pneumonia, scarlet fever, and tuberculosis (TB), were examined. First, the expected respiratory infectious cases where no public health measures are in place are estimated using the seasonal autoregressive integrated moving average (SARIMA) model. Then the expected number of cases and the observed cases were compared. The results showed a significant drop in the incidence of respiratory infectious diseases by an average of 61%. The reduction in hospitalization is significant for influenza, measles, pertussis, pneumonia, and scarlet fever (p < 0.05), while insignificant for TB (p = 0.54). The notable decrease in the incidence of cases is ascribed to the implementation of public health measures that minimized the opportunity for spread of disease. This decline in cases following relaxation of pandemic countermeasure is contingent on its scope and nature, and it is proof that selective physical distancing, hand hygiene, and use of face masks in public places is a viable route for mitigating respiratory morbidities.

The rising of old foes: impact of lockdown periods on "non-SARS-CoV-2" viral respiratory and gastrointestinal infections

BACKGROUND

During COVID-19-related public health non-pharmaceutical prevention measures, such as social distancing, lockdown periods and use of face masks, a decrease in viral respiratory and gastroenterological infections was observed worldwide. Following discontinuation of preventative measures, a potential increase of respective infections outside of their usual seasons was a matter of concern.

METHOD

We aimed to illustrate annual distribution of confirmed viral infections between 2017 and 2021 based on 32,506 clinical samples in a German pediatric tertiary care center and to explore the impact of the COVID-19 pandemic on the epidemiology of these infections in children.

RESULTS

While a decrease in overall viral infections was observed during the first and second lockdown period, an extraordinary increase in the number of viral respiratory infections, predominantly caused by human Rhino-/Enterovirus and respiratory syncytial virus (RSV), was observed after relaxation of preventive measures. Notably, Rhino-/Enterovirus infections increased 4-fold (2020 vs. 2019) and 16-fold (2021 vs. 2019). The occurrence of RSV was observed beginning from June to August 2021 and reached an all-time record with a 25- to 50-fold increase in numbers in September and October 2021 in relation to previous pre-pandemic years (2017-2019). In contrast, for non-respiratory viruses (i.e. Rota-/Norovirus), the effect on respective seasonal patterns was only minimal compared to previous years.

CONCLUSION

The observed increase in respiratory infections in children is worrying and is already causing hospitals to become overburdened. Enhanced vigilance will be key to face clinical challenges due to these epidemiological changes in viral disease patterns in the months to come.

Severity of Illness in Bronchiolitis Amid Unusual Seasonal Pattern During the COVID-19 Pandemic

OBJECTIVE

We aimed to characterize recent trends in bronchiolitis at US children's hospitals and to compare severity of illness in bronchiolitis in the most recent year to the previous seasonal epidemics.

METHODS

This is a cross-sectional study of visits for bronchiolitis in infants <24 months old from October 2016 to September 2021 at 46 US children's hospitals participating in the Pediatric Health Information Systems database. Study years were defined by 12-month periods beginning in October to account for typical winter epidemics that crossover calendar years. We used logistic and Fourier Poisson regression models to examine trends in outcomes and compare seasonality, respectively.

RESULTS

The study included 389 411 emergency visits for bronchiolitis. Median age of infants with bronchiolitis was higher in October 2020 to September 2021 compared to previous epidemics (8 and 6 months, respectively, P < .001) The odds of hospitalization, ICU admission, invasive mechanical ventilation, and noninvasive ventilation did not differ in October 2020 to September 2021 compared to previous epidemics from October 2016 to September 2020 (all P > .05 for unadjusted models and models adjusted for age). Seasonality varied significantly among these 2 periods (P < .001).

CONCLUSIONS

Although the seasonality of bronchiolitis differed in October 2020 to September 2021, severity of illness in infants with bronchiolitis was consistent with previous epidemics.

Effect of the COVID-19 Lockdown on Asthma Biological Rhythms

Asthma has a striking temporal character, in which time-of-day, patient age, and season each influence disease activity. The extent to which rhythms in asthma activity reflect exposure to specific disease triggers remains unclear. In this study, we examined how virus mitigation strategies enacted during the COVID-19 pandemic ("lockdown measures") affected rhythms in asthma clinical activity in children. To this end, we retrospectively analyzed asthma clinical presentations in children aged <18 years to our regional academic medical center, comparing 4 years of medical records prior to COVID-19 lockdown measures with the 12 months immediately after the institution of such measures. We correlated these data to positive viral test results, febrile seizures, and allergic clinical surrogates (allergic reaction visits and Emergency Department [ED] antihistamine prescriptions, respectively) over the same time frame. In the 12 months following the institution of the COVID-19 lockdown, positivity rates for common respiratory viruses dropped by 70.2% and ED visits for asthma among children dropped by 62% compared to pre-COVID years. Lockdown suppressed seasonal variation in positive viral tests and asthma ED visits, while diurnal rhythms in asthma visits were unchanged. Asthma seasonality correlated most strongly with rhinovirus positivity both before and after the institution of COVID lockdown measures. Altogether, our data support a causal role for viruses in driving seasonal variability in asthma exacerbations in children.

Epidemiology of respiratory virus before and during COVID-19 pandemic

The COVID pandemic has forcefully turned the spotlight on the importance of the diagnosis of respiratory virus infections. Viruses have always been a frequent and common cause of respiratory tract infections. Rapid molecular diagnostics applied to the diagnostics of respiratory virus infections has revolutionized microbiology laboratories only a few years ago. Few studies illustrate the epidemiology of respiratory viruses, and fewer still those that have compared the pre-pandemic to the pandemic period. During the first year of the pandemic (2020-2021) it was clear to everyone to witness a sudden disappearance of the circulation of all the other respiratory viruses, especially those typically isolated during the winter time, such as RSV and Influenza virus. In our study we wanted to verify this phenomenon and to study the epidemiology of our local reality, analyzing three consecutive flu seasons (2018-2019, 2019-2020, 2020-2021). The results lead us to note that the prevalence of positivity to respiratory virus infections went from 49.8% (2018-2019) and 39% (2019-2020) to 13.4% (2020-2021). This decrease is at least partly attributable to the security measures adopted (social distancing and mask), but it certainly opens up new scenarios when the restriction measures will be terminated. We believe such studies can provide real-world evidence of the effectiveness of public health interventions implemented during current and future pandemics.

Epidemiological changes of common respiratory viruses in children during the COVID-19 pandemic

A variety of non‐pharmaceutical interventions (NPIs) have been implemented to control the transmission of COVID‐19 in China. The effect of NPIs on other common respiratory viruses in children of different age groups has not been examined thus far. Respiratory specimens of children were collected to detect common childhood respiratory viruses, including influenza A (FluA), influenza B (FluB), adenovirus, and respiratory syncytial virus (RSV), at the Children's Hospital of Zhejiang University School of Medicine from January 1, 2019 to December 31, 2020. The epidemiological characteristics of the respiratory viruses in 2020 were compared with those in 2019. From January 2019 to December 2020, 165 622 specimens were collected. The proportion of infants aged 0−28 days (683, 2.24% vs. 1295, 0.96%, p = 0.000) and 1−12 months (8560, 28.12% vs. 20 875, 15.43%, p = 0.000) in 2020 increased significantly compared with that in 2019. There were two obvious increases in April and September in the number of specimens in children aged 4−6 years and >7 years. FluA, FluB, and RSV's age distribution patterns were surprisingly consistent with each other in 2020, and the positive rates of children aged 1−12 months were the highest in all age groups (FluA: 4.45%, FluB: 3.30%, RSV: 7.35%). Our study further confirms that the NPIs significantly decreased the transmission of common childhood respiratory viruses. The change in circulation characteristics of common respiratory viruses of children in different age groups varied. Therefore, we recommend that different protection strategies should be introduced for children of different age groups.

The epidemiological characteristics of common childhood respiratory viruses varied during the COVID‐19 pandemic. The non‐pharmaceutical interventions significantly decreased the transmission of common childhood respiratory viruses. Different protection strategies should be introduced for children of varying age groups. COVID‐19 article requiring a fast track process.

Impact of the State of Emergency during the COVID-19 Pandemic in 2020 on Asthma Exacerbations among Children in Kobe City, Japan

The coronavirus disease (COVID-19) pandemic altered environmental factors. We studied the impact of these changes on asthma exacerbation (AE) by comparing the AE-related environmental factors between COVID-19 (2020) and pre-COVID-19 (2011–2019) eras. Between 2011 and 2020, 278,465 children (<16 years old) visited our emergency department, and 7476 were diagnosed with AE. The number of patients showed spring and fall peaks in 2011–2019. Multivariate analyses showed significant positive relationships of the number of AE patients with the average temperature among all patients and 0–5-year-olds and with sulfur dioxide (SO₂) levels in 2011–2019 among 0–5-year-olds. Although the spring peak in the number of patients was not observed in 2020 after declaration of a state of emergency, the fall peak was again observed after the state of emergency was lifted. No changes in average temperature were detected, but SO₂ was significantly reduced following declaration of the state of emergency in 2020. Therefore, SO₂ reduction might have contributed to the disappearance of the peak of AE. However, a fall peak was observed again in 2020, although SO₂ levels continued to be low. These data suggest that person to person interaction seems to be associated with AE, presumably due to unknown viral infections.

Modelling the impact of travel restrictions on COVID-19 cases in Hong Kong in early 2020

BACKGROUND

Coronavirus Disease 2019 (COVID-19) led to pandemic that affected almost all countries in the world. Many countries have implemented border restriction as a public health measure to limit local outbreak. However, there is inadequate scientific data to support such a practice, especially in the presence of an established local transmission of the disease.

OBJECTIVE

To apply a metapopulation Susceptible-Exposed-Infectious-Recovered (SEIR) model with inspected migration to investigate the effect of border restriction as a public health measure to limit outbreak of coronavirus disease 2019.

METHODS

We apply a modified metapopulation SEIR model with inspected migration with simulating population migration, and incorporating parameters such as efficiency of custom inspection in blocking infected travelers in the model. The population sizes were retrieved from government reports, while the number of COVID-19 patients were retrieved from Hong Kong Department of Health and China Centre for Disease Control (CDC) data. The R₀ was obtained from previous clinical studies.

RESULTS

Complete border closure can help to reduce the cumulative COVID-19 case number and mortality in Hong Kong by 13.99% and 13.98% respectively. To prevent full occupancy of isolation facilities in Hong Kong; effective public health measures to reduce local R₀ to below 1.6 was necessary, apart from having complete border closure.

CONCLUSIONS

Early complete travel restriction is effective in reducing cumulative cases and mortality. However, additional anti-COVID-19 measures to reduce local R₀ to below 1.6 are necessary to prevent COVID-19 cases from overwhelming hospital isolation facilities.