The missing season: The impacts of the COVID-19 pandemic on influenza

Internet-based Surveillance Systems and Infectious Diseases Prediction: An Updated Review of the Last 10 Years and Lessons from the COVID-19 Pandemic

The last decade has seen major advances and growth in internet-based surveillance for infectious diseases through advanced computational capacity, growing adoption of smart devices, increased availability of Artificial Intelligence (AI), alongside environmental pressures including climate and land use change contributing to increased threat and spread of pandemics and emerging infectious diseases. With the increasing burden of infectious diseases and the COVID-19 pandemic, the need for developing novel technologies and integrating internet-based data approaches to improving infectious disease surveillance is greater than ever. In this systematic review, we searched the scientific literature for research on internet-based or digital surveillance for influenza, dengue fever and COVID-19 from 2013 to 2023. We have provided an overview of recent internet-based surveillance research for emerging infectious diseases (EID), describing changes in the digital landscape, with recommendations for future research directed at public health policymakers, healthcare providers, and government health departments to enhance traditional surveillance for detecting, monitoring, reporting, and responding to influenza, dengue, and COVID-19.

Study on the impact of meteorological factors on influenza in different periods and prediction based on artificial intelligence RF-Bi-LSTM algorithm: to compare the COVID-19 period with the non-COVID-19 period

OBJECTIVE

At different times, public health faces various challenges and the degree of intervention measures varies. The research on the impact and prediction of meteorology factors on influenza is increasing gradually, however, there is currently no evidence on whether its research results are affected by different periods. This study aims to provide limited evidence to reveal this issue.

METHODS

Daily data on influencing factors and influenza in Xiamen were divided into three parts: overall period (phase AB), non-COVID-19 epidemic period (phase A), and COVID-19 epidemic period (phase B). The association between influencing factors and influenza was analysed using generalized additive models (GAMs). The excess risk (ER) was used to represent the percentage change in influenza as the interquartile interval (IQR) of meteorology factors increases. The 7-day average daily influenza cases were predicted using the combination of bi-directional long short memory (Bi-LSTM) and random forest (RF) through multi-step rolling input of the daily multifactor values of the previous 7-day.

RESULTS

In periods A and AB, air temperature below 22 °C was a risk factor for influenza. However, in phase B, temperature showed a U-shaped effect on it. Relative humidity had a more significant cumulative effect on influenza in phase AB than in phase A (peak: accumulate 14d, AB: ER = 281.54, 95% CI = 245.47 ~ 321.37; A: ER = 120.48, 95% CI = 100.37 ~ 142.60). Compared to other age groups, children aged 4-12 were more affected by pressure, precipitation, sunshine, and day light, while those aged ≥ 13 were more affected by the accumulation of humidity over multiple days. The accuracy of predicting influenza was highest in phase A and lowest in phase B.

CONCLUSIONS

The varying degrees of intervention measures adopted during different phases led to significant differences in the impact of meteorology factors on influenza and in the influenza prediction. In association studies of respiratory infectious diseases, especially influenza, and environmental factors, it is advisable to exclude periods with more external interventions to reduce interference with environmental factors and influenza related research, or to refine the model to accommodate the alterations brought about by intervention measures. In addition, the RF-Bi-LSTM model has good predictive performance for influenza.

Competition to Explain Stable Prevalence of Seasonal Viral Respiratory Infections in Temperate Climates

The prevalence of seasonal viral respiratory infections in temperate climates is relatively stable, but individual viruses vary. This phenomenon is not explained via the conventional view of influenza seasonality which is still incomplete. The viral-flow theory, an outsider theory about the seasonality of influenza, where insects buffer viruses, is able to explain the stable prevalence of viral respiratory infections. Alternative hypotheses to explain this phenomenon are discussed.

Questionable Immunity to Mumps among Healthcare Workers in Italy-A Cross-Sectional Serological Study

Highly contagious diseases, such as mumps, are a global concern as new epidemics continue to emerge, even in highly vaccinated populations. The risk of transmission and spread of these viruses is even higher for individuals who are more likely to be exposed, including healthcare workers (HCWs). In healthcare settings, both HCWs and patients are at risk of infection during the care process, potentially leading to nosocomial epidemic outbreaks. Mumps is often underestimated compared with measles and rubella, despite being milder and less likely to spread. In fact, the risk of complications following mumps infection is extremely high, especially if the disease occurs in adulthood. The measles-mumps-rubella (MMR) vaccine has been shown to be an excellent preventive measure. Unfortunately, the mumps component appears to be less effective in inducing immunity than those for measles and rubella (two-dose effectiveness of 85%, 95% and 97%, respectively). The main aim of our study was to investigate the prevalence of detectable mumps antibodies (serum IgG antibodies) in a cohort of Italian and foreign HCWs in relation to personal and occupational factors. We included in the study 468 subjects who underwent health surveillance at the Occupational Medicine Unit of the Tor Vergata Polyclinic in Rome during the period from January 2021 to March 2023. In our study, the proportion of HCWs found to be unprotected against mumps was very high (8.3%), and those found to be immune are below the WHO threshold for herd immunity (95%). From our data, it seems essential that all occupational health services carry out an accurate screening with a dose of anti-mumps antibodies to assess serological protection before starting a job, regardless of an individual's vaccination history. This approach is proving to be beneficial, accurate, as it allows all serologically non-immune individuals to be vaccinated in the workplace, including those who would be protected by their vaccination history but have lost the antibody response.

Markovian Approach for Exploring Competitive Diseases with Heterogeneity-Evidence from COVID-19 and Influenza in China

Due to the complex interactions between multiple infectious diseases, the spreading of diseases in human bodies can vary when people are exposed to multiple sources of infection at the same time. Typically, there is heterogeneity in individuals' responses to diseases, and the transmission routes of different diseases also vary. Therefore, this paper proposes an SIS disease spreading model with individual heterogeneity and transmission route heterogeneity under the simultaneous action of two competitive infectious diseases. We derive the theoretical epidemic spreading threshold using quenched mean-field theory and perform numerical analysis under the Markovian method. Numerical results confirm the reliability of the theoretical threshold and show the inhibitory effect of the proportion of fully competitive individuals on epidemic spreading. The results also show that the diversity of disease transmission routes promotes disease spreading, and this effect gradually weakens when the epidemic spreading rate is high enough. Finally, we find a negative correlation between the theoretical spreading threshold and the average degree of the network. We demonstrate the practical application of the model by comparing simulation outputs to temporal trends of two competitive infectious diseases, COVID-19 and seasonal influenza in China.

Evaluation of an automated feedback intervention to improve antibiotic prescribing among primary care physicians (OPEN Stewardship): a multinational controlled interrupted time-series study

Tools to advance antimicrobial stewardship in the primary health care setting, where most antimicrobials are prescribed, are urgently needed. The aim of this study was to evaluate OPEN Stewarship (Online Platform for Expanding aNtibiotic Stewardship), an automated feedback intervention, among a cohort of primary care physicians. We performed a controlled, interrupted time-series study of 32 intervention and 725 control participants, consisting of primary care physicians from Ontario, Canada and Southern Israel, from October 2020 to December 2021. Intervention participants received three personalized feedback reports targeting several aspects of antibiotic prescribing. Study outcomes (overall prescribing rate, prescribing rate for viral respiratory conditions, prescribing rate for acute sinusitis, and mean duration of therapy) were evaluated using multilevel regression models. We observed a decrease in the mean duration of antibiotic therapy (IRR = 0.94; 95% CI: 0.90, 0.99) in intervention participants during the intervention period. We did not observe a significant decline in overall antibiotic prescribing (OR = 1.01; 95% CI: 0.94, 1.07), prescribing for viral respiratory conditions (OR = 0.87; 95% CI: 0.73, 1.03), or prescribing for acute sinusitis (OR = 0.85; 95% CI: 0.67, 1.07). In this antimicrobial stewardship intervention among primary care physicians, we observed shorter durations of therapy per antibiotic prescription during the intervention period. The COVID-19 pandemic may have hampered recruitment; a dramatic reduction in antibiotic prescribing rates in the months before our intervention may have made physicians less amenable to further reductions in prescribing, limiting the generalizability of the estimates obtained.IMPORTANCEAntibiotic overprescribing contributes to antibiotic resistance, a major threat to our ability to treat infections. We developed the OPEN Stewardship (Online Platform for Expanding aNtibiotic Stewardship) platform to provide automated feedback on antibiotic prescribing in primary care, where most antibiotics for human use are prescribed but where the resources to improve antibiotic prescribing are limited. We evaluated the platform among a cohort of primary care physicians from Ontario, Canada and Southern Israel from October 2020 to December 2021. The results showed that physicians who received personalized feedback reports prescribed shorter courses of antibiotics compared to controls, although they did not write fewer antibiotic prescriptions. While the COVID-19 pandemic presented logistical and analytical challenges, our study suggests that our intervention meaningfully improved an important aspect of antibiotic prescribing. The OPEN Stewardship platform stands as an automated, scalable intervention for improving antibiotic prescribing in primary care, where needs are diverse and technical capacity is limited.

Comparison of geological clusters between influenza and COVID-19 in Thailand with unsupervised clustering analysis

The coronavirus disease (COVID-19) pandemic has considerably impacted public health, including the transmission patterns of other respiratory pathogens, such as the 2009 pandemic influenza (H1N1). COVID-19 and influenza are both respiratory infections that started with a lack of vaccination-based immunity in the population. However, vaccinations have been administered over time, resulting in a transition of the status of both diseases from a pandemic to an endemic. In this study, unsupervised clustering techniques were used to identify clusters of disease trends in Thailand. The analysis incorporated three distinct surveillance datasets: the pandemic influenza outbreak, influenza in the endemic stage, and the early stages of COVID-19. The analysis demonstrated a significant difference in the distribution of provinces between Cluster -1, representing those with unique transmission patterns, and the other clusters, indicating provinces with similar transmission patterns among their members. Specifically, for Pandemic Influenza, the ratio was 61:16, while for Pandemic COVID-19, it was 65:12. In contrast, Endemic Influenza exhibited a ratio of 46:31, with a notable emergence of more clustered provinces in the southern, western, and central regions. Furthermore, a pair of provinces with highly similar spreading patterns were identified during the pandemic stages of both influenza and COVID-19. Although the similarity decreased slightly for endemic influenza, they still belonged to the same cluster. Our objective was to identify the transmission patterns of influenza and COVID-19, with the aim of providing quantitative and spatial information to aid public health management in preparing for future pandemics or transitioning into an endemic phase.

Epidemiology and burden of Severe Acute Respiratory Infections (SARI) in the aftermath of COVID-19 pandemic: A prospective sentinel surveillance study in a Tunisian Medical ICU, 2022/2023

BACKGROUND

Severe Acute Respiratory Infections (SARI) caused by influenza and other respiratory viruses pose significant global health challenges, and the COVID-19 pandemic has further strained healthcare systems. As the focus shifts from the pandemic to other respiratory infections, assessing the epidemiology and burden of SARI is crucial for healthcare planning and resource allocation. Aim: to understand the impact of the post-pandemic period on the epidemiology of SARI cases, clinical outcomes, and healthcare resource utilization in Tunisia.

METHODS

This is a prospective study conducted in a Tunisian MICU part of a national sentinel surveillance system, focusing on enhanced SARI surveillance. SARI cases from week 39/2022, 26 September to week 19/2023, 13 May were included, according to a standardized case definition. Samples were collected for virological RT-PCR testing, and an electronic system ensured standardized and accurate data collection. Descriptive statistics were performed to assess epidemiology, trends, and outcomes of SARI cases, and univariate/multivariate analyses to assess factors associated with mortality.

RESULTS

Among 312 MICU patients, 164 SARI cases were identified during the study period. 64(39%) RT-PCR were returned positive for at least one pathogen, with influenza A and B strains accounting for 20.7% of cases at the early stages of the influenza season. The MICU experienced a significant peak in admissions during weeks 1-11/2023, leading to resource mobilization and the creation of a surge unit. SARI cases utilized 1664/3120 of the MICU-stay days and required 1157 mechanical ventilation days. The overall mortality rate among SARI cases was 22.6%. Age, non-COPD, and ARDS were identified as independent predictors of mortality.

CONCLUSIONS

The present study identified a relatively high rate of SARI cases, with 39% positivity for at least one respiratory virus, with influenza A and B strains occurring predominantly during the early stages of the influenza season. The findings shed light on the considerable resource utilization and mortality associated with these infections, underscoring the urgency for proactive management and efficient resource allocation strategies.

Knowledge, attitudes, and practices (KAP) toward seasonal influenza vaccine among college students under the COVID-19 pandemic in South China

BACKGROUND

The control measures of the coronavirus disease 2019 (COVID-19) pandemic had influenced the activity of the influenza virus, and we were wondering the knowledge, attitudes, and practices (KAP) toward seasonal influenza vaccine among college students were having at the context of the COVID-19 pandemic.

METHODS

Online questionnaire survey of the college students was conducted and the data was collected anonymously, cross-sectional study were used to describe the distribution of the KAP.

RESULTS

There were 815 respondents in our study. Most participants have a high recognition of the effectiveness and safety of the influenza vaccine. However, a low awareness rate of influenza vaccine knowledge and vaccination rate (18%) against influenza was observed among college students. The education level and major would have a higher weight on the influence of KAP among the college students. Binary logistic regression analysis showed that the sex (OR = 2.163, p < .001), age (OR = 2.242, p < .001), heard of the influenza vaccine (OR = 2.655, p = .014), and "How necessary do you think vaccinating every year is?" (OR = 3.947, p < .001) of the college students were the main factors that affect the KAP on influenza vaccination.

CONCLUSIONS

Our study provided an insight into the KAP of influenza vaccine among college students in South China. The vaccination rate and acceptability of influenza vaccine in college students are higher than that in the whole population.

Epidemic Characteristics, Spatiotemporal Pattern, and Risk Factors of Other Infectious Diarrhea in Fujian Province From 2005 to 2021: Retrospective Analysis

BACKGROUND

Other infectious diarrhea (OID) continues to pose a significant public health threat to all age groups in Fujian Province. There is a need for an in-depth analysis to understand the epidemiological pattern of OID and its associated risk factors in the region.

OBJECTIVE

In this study, we aimed to describe the overall epidemic characteristics and spatiotemporal pattern of OID in Fujian Province from 2005 to 2021 and explore the linkage between sociodemographic and environmental factors and the occurrence of OID within the study area.

METHODS

Notification data for OID in Fujian were extracted from the China Information System for Disease Control and Prevention. The spatiotemporal pattern of OID was analyzed using Moran index and Kulldorff scan statistics. The seasonality of and short-term impact of meteorological factors on OID were examined using an additive decomposition model and a generalized additive model. Geographical weighted regression and generalized linear mixed model were used to identify potential risk factors.

RESULTS

A total of 388,636 OID cases were recorded in Fujian Province from January 2005 to December 2021, with an average annual incidence of 60.3 (SD 16.7) per 100,000 population. Children aged <2 years accounted for 50.7% (196,905/388,636) of all cases. There was a steady increase in OID from 2005 to 2017 and a clear seasonal shift in OID cases from autumn to winter and spring between 2005 and 2020. Higher maximum temperature, atmospheric pressure, humidity, and precipitation were linked to a higher number of deseasonalized OID cases. The spatial and temporal aggregations were concentrated in Zhangzhou City and Xiamen City for 17 study years. Furthermore, the clustered areas exhibited a dynamic spreading trend, expanding from the southernmost Fujian to the southeast and then southward over time. Factors such as densely populated areas with a large <1-year-old population, less economically developed areas, and higher pollution levels contributed to OID cases in Fujian Province.

CONCLUSIONS

This study revealed a distinct distribution of OID incidence across different population groups, seasons, and regions in Fujian Province. Zhangzhou City and Xiamen City were identified as the major hot spots for OID. Therefore, prevention and control efforts should prioritize these specific hot spots and highly susceptible groups.

High number of seizures and unconsciousness in patients with SARS-CoV-2 omicron variants: a retrospective study

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron variants are now a pandemic. There are differences in clinical features in SARS-CoV-2 variants and we conducted this study to assess the clinical features of coronavirus disease (COVID-19) in children with SARS-CoV-2 omicron variants. The study included children with COVID-19 arrivedto Tokyo Metropolitan Toshima Hospital between January 2020 and October 2022. The clinical features of 214 children with SARS-CoV-2 non-omicron variants and 557 children with omicron variants were compared. In the SARS-CoV-2 omicron variant group, more patients had fever, sore throat, nausea and/or vomiting, and seizures and/or disorders of consciousness. In SARS-CoV-2 non-omicron variants, there was only one patient with seizure and/or unconsciousness whereas there were 92 children in omicron variants. Among these 92 patients, 46 (49%) were diagnosed with simple febrile seizures; 23 (25%), with complex febrile seizures; 10 (11%) with status epilepticus; and two (2%) with encephalopathy. Their mean age was 4.0 ± 3.0 years-a wider age distribution than that in other febrile seizures but similar to that in febrile seizures in patients with influenza. SARS-CoV-2 omicron variants are likely to cause seizures and unconsciousness in children and their age distribution was wider than other febrile seizures patients but similar to those in influenza patients. In clinical practice in patients with COVID-19 and influenza, clinicians should be aware of these features.

The interplay between susceptibility and vaccine effectiveness control the timing and size of an emerging seasonal influenza wave in England

Relaxing social distancing measures and reduced level of influenza over the last two seasons may lead to a winter 2022 influenza wave in England. We used an established model for influenza transmission and vaccination to evaluate the rolled out influenza immunisation programme over October to December 2022. Specifically, we explored how the interplay between pre-season population susceptibility and influenza vaccine efficacy control the timing and the size of a possible winter influenza wave. Our findings suggest that susceptibility affects the timing and the height of a potential influenza wave, with higher susceptibility leading to an earlier and larger influenza wave while vaccine efficacy controls the size of the peak of the influenza wave. With pre-season susceptibility higher than pre-COVID-19 levels, under the planned vaccine programme an early influenza epidemic wave is possible, its size dependent on vaccine effectiveness against the circulating strain. If pre-season susceptibility is low and similar to pre-COVID levels, the planned influenza vaccine programme with an effective vaccine could largely suppress a winter 2022 influenza outbreak in England.

Impact of COVID-19 Pandemic on Respiratory Syncytial Virus (RSV) Prophylaxis Program: A Tertiary-Care Center Experience

OBJECTIVES

The purpose of this investigation was to evaluate the effects of the COVID-19 pandemic on the respiratory syncytial virus (RSV) prevention program at our institution across three time frames: 2019-2020, 2020-2021, and 2021-2022.

METHODS

We carried out a descriptive, single-site observational study spanning four years, from June 2019 to June 2022. Our study included patients in our institution's RSV program who met our enrollment criteria. We collected information about the number of children receiving immunoprophylaxis, immunoprophylaxis doses, and RSV risk factors.

RESULTS

The number of patients receiving immunoprophylaxis dropped across the three periods, from 315 patients in the first period (2019-2020) to 176 in the second period (2020-2021), and further decreased to 128 in the third period (2021-2022). Following the COVID-19 pandemic, there was a 50% reduction in the number of patients receiving immunoprophylaxis. The proportion of RSV-infected patients remained relatively similar in the first and second periods (2.86% and 2.27%, respectively) but increased in the third period (5.47%). In the first period, most patients (60.32%) received seven doses, 11.75% got four to six doses, and 27.95% received three doses or fewer. The second period saw 59.66% of patients receiving four to six doses and 40.34% receiving three doses or fewer. In the third period, a mere 9.38% received four to five doses, while 90.63% got three doses or fewer.

CONCLUSIONS

While preventative measures associated with COVID-19 may have helped reduce the number of RSV cases, the pandemic seems to have caused a significant decrease in the number of children receiving immunoprophylaxis and the doses of immunoprophylaxis. More extensive, multicenter research is needed to understand the impact of the COVID-19 pandemic on RSV immunoprophylaxis, its activity, and seasonal patterns fully.

A seesaw effect between COVID-19 and influenza during 2020-2023 in WHO regions

BACKGROUND

Seasonal influenza activity showed a sharp decline in activity at the beginning of the Corona Virus Disease 2019 (COVID-19) emergence. Whether there is an epidemiological correlation between the dynamic of two respiratory infectious diseases and their future trends needs to be explored.

OBJECTIVE

To assess the correlation between COVID-19 and influenza activity and estimate their upcoming epidemiological trends.

METHODS

We retrospectively described the dynamics of COVID-19 and influenza in six World Health Organization (WHO) regions from January 2020-March 2023, and used the long short-term memory (LSTM) machine learning model to learn potential patterns of previously observed activity to predict trends for the next sixteen weeks. Finally, the past and future correlation in epidemiology between two respiratory infectious diseases was assessed by the Spearman correlation coefficients.

RESULTS

With the emergence of original strain and other severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, influenza activity kept below 10% for more than one year in the six WHO regions. Subsequently, it gradually rose as the Delta activity dropped, but still peaked below Delta. During the Omicron pandemic and the upcoming period, the two increased as each other's activity decreased, becoming interactively dominant more than once and lasting 3-4 months. Correlation analysis showed that COVID-19 and influenza activity presented a predominantly negative correlation with coefficients above -0.3 in WHO regions, especially during the Omicron pandemic and the estimated upcoming period. They had a transient positive correlation in the European Region of WHO (EURO), and the Western Pacific Region of WHO (WPRO) when multiple dominant strains were mixed pandemic.

CONCLUSIONS

Influenza activity and former seasonal epidemiological patterns are shaken by the COVID-19 pandemic. Their activities are moderately and above inversely correlated, oppressing and competing with each other, showing a seesaw effect. In the post-pandemic era of COVID-19, the seesaw trends may be more prominent, prompting the possibility of using one another as early warning signals for future estimates and conducting optimized annual vaccine campaigns.

CLINICALTRIAL

Behavioral changes of preventive activities of influenza among children in satellite cities of a metropolitan area of Tokyo, Japan, by the COVID-19 pandemic

OBJECTIVE

In children in a metropolitan area of Tokyo, Japan, behavioral change and influenza infection associated with the frequency of nonpharmaceutical interventions (NPI) was assessed from the 2018-2019 season (Preseason) and the 2020-2021 season (coronavirus disease 2019 [COVID-19] season).

METHODS

We conducted an exclusive survey among children attending preschool, elementary school, and junior high school in the Toda and Warabi regions, Japan, during the 2018-2019 (Preseason, distributed via mail) and 2020-2021 seasons (COVID-19 season, conducted online). The proportion of preventive activities (hand washing, face mask-wearing, and vaccination) was compared in the Preseason with that of the COVID-19 season. The multivariate logistic regression model was further applied to calculate the adjusted odds ratio (AOR) with 95% confidence intervals (CIs) for influenza infection associated with NPI frequency (hand washing and face mask wearing) in each Preseason and COVID-19 season.

RESULTS

The proportion of vaccinated children who carried out hand washing and face mask wearing was remarkably higher during the COVID-19 season (48.8%) than in the Preseason (18.2%). A significant influenza infection reduction was observed among children who washed hands and wore face masks simultaneously (AOR, 0.87; 95% CI, 0.76-0.99; P = 0.033).

CONCLUSIONS

A strong interest and performance in the intensive measures for the prevention of influenza under the COVID-19 pandemic was demonstrated. Positive association was observed from a combination of NPI, hand washing, and face mask-wearing and influenza infection. This study's findings could help in activities or preventive measures against influenza and other communicable diseases in children.

Global patterns and drivers of influenza decline during the COVID-19 pandemic

OBJECTIVES

The influenza circulation reportedly declined during the COVID-19 pandemic in many countries. The occurrence of this change has not been studied worldwide nor its potential drivers.

METHODS

The change in the proportion of positive influenza samples reported by country and trimester was computed relative to the 2014-2019 period using the FluNet database. Random forests were used to determine predictors of change from demographical, weather, pandemic preparedness, COVID-19 incidence, and pandemic response characteristics. Regression trees were used to classify observations according to these predictors.

RESULTS

During the COVID-19 pandemic, the influenza decline relative to prepandemic levels was global but heterogeneous across space and time. It was more than 50% for 311 of 376 trimesters-countries and even more than 99% for 135. COVID-19 incidence and pandemic preparedness were the two most important predictors of the decline. Europe and North America initially showed limited decline despite high COVID-19 restrictions; however, there was a strong decline afterward in most temperate countries, where pandemic preparedness, COVID-19 incidence, and social restrictions were high; the decline was limited in countries where these factors were low. The "zero-COVID" countries experienced the greatest decline.

CONCLUSION

Our findings set the stage for interpreting the resurgence of influenza worldwide.

Decline in reported measles cases in Italy in the COVID-19 era, January 2020 - July 2022: The need to prevent a resurgence upon lifting non-pharmaceutical pandemic measures

From January 2020 to July 2022, 120 measles cases were reported to the Italian national surveillance system, of which 105 had symptom onset in 2020, nine in 2021 and six in the first seven months of 2022. This represents a sharp decline compared to the time period immediately preceding the COVID-19 pandemic, most likely due to the non-pharmaceutical interventions implemented to prevent SARS-CoV2 transmission. Of 105 cases reported in 2020, 103 acquired the infection before a national lockdown was instituted on 9 March 2020. Overall, one quarter of cases reported at least one complication. As non-pharmaceutical pandemic measures are being eased worldwide, and considering measles seasonality, infectiousness, and its potential severity, it is important that countries ensure high vaccination coverage and close immunity gaps, to avoid risk of future outbreaks.

Sharp decline in rates of community respiratory viral detection among patients at the National Institutes of Health Clinical Center during the coronavirus disease 2019 (COVID-19) pandemic

OBJECTIVES

To analyze the frequency and rates of community respiratory virus infections detected in patients at the National Institutes of Health Clinical Center (NIHCC) between January 2015 and March 2021, comparing the trends before and during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

We conducted a retrospective study comparing frequency and rates of community respiratory viruses detected in NIHCC patients between January 2015 and March 2021. Test results from nasopharyngeal swabs and washes, bronchoalveolar lavages, and bronchial washes were included in this study. Results from viral-challenge studies and repeated positives were excluded. A quantitative data analysis was completed using cross tabulations. Comparisons were performed using mixed models, applying the Dunnett correction for multiplicity.

RESULTS

Frequency of all respiratory pathogens declined from an annual range of 0.88%-1.97% between January 2015 and March 2020 to 0.29% between April 2020 and March 2021. Individual viral pathogens declined sharply in frequency during the same period, with no cases of influenza A/B orparainfluenza and 1 case of respiratory syncytial virus (RSV). Rhino/enterovirusdetection continued, but with a substantially lower frequency of 4.27% between April 2020 and March 2021, compared with an annual range of 8.65%-18.28% between January 2015 and March 2020.

CONCLUSIONS

The decrease in viral respiratory infections detected in NIHCC patients during the pandemic was likely due to the layered COVID-19 prevention and mitigation measures implemented in the community and the hospital. Hospitals should consider continuing the use of nonpharmaceutical interventions in the future to prevent nosocomial transmission of respiratory viruses during times of high community viral load.

Influenza vaccination coverage among health-care workers during the COVID-19 epidemic in 2020/2021 influenza season: Evidence from a web-based survey in northwestern China

Vaccinating health-care workers against influenza during the COVID-19 pandemic can effectively prevent and control influenza and reduce COVID-19 strain on health systems. This study was conducted to explore influenza vaccination coverage and determinants among health-care workers during the COVID-19 pandemic in 2020/2021 influenza season in Ningxia. This cross-sectional survey included demographic characteristics of health-care workers, influenza vaccination status, reasons for not getting vaccinated, and whether influenza vaccination was recommended for others. We found that influenza vaccine rate of health-care workers was 39.6%. A binary logistic regression analysis showed that health-care workers' vaccination coverage was higher when the individuals were aware of the effect of the influenza vaccine (OR = 0.624, 95% CI: 0.486-0.802). Health-care workers who from internal medicine (OR = 1.494, 95% CI: 1.146-1.948), pediatrics (OR = 2.091, 95% CI: 1.476-2.962), and surgery departments (OR = 1.373, 95% CI: 1.014-1.859) had a lower coverage than those who worked in vaccination and infectious disease departments. The main reasons that some stated for not getting vaccinated were that they felt it was unnecessary (52.22%). Health-care workers who were vaccinated against influenza were more likely to recommend influenza vaccination to their patients than health-care workers who had not been vaccinated. The incidence of influenza among health-care workers was higher than that of the general population in Ningxia. Under the policy of voluntary and self-pay influenza vaccination in Ningxia, the coverage rate of influenza vaccine among health-care workers was far below the vaccination requirements of influenza vaccine in influenza season even during the COVID-19 epidemic.

Viral Coinfections in Hospitalized Coronavirus Disease 2019 Patients Recruited to the International Severe Acute Respiratory and Emerging Infections Consortium WHO Clinical Characterisation Protocol UK Study

Background

We conducted this study to assess the prevalence of viral coinfection in a well characterized cohort of hospitalized coronavirus disease 2019 (COVID-19) patients and to investigate the impact of coinfection on disease severity.

Methods

Multiplex real-time polymerase chain reaction testing for endemic respiratory viruses was performed on upper respiratory tract samples from 1002 patients with COVID-19, aged <1 year to 102 years old, recruited to the International Severe Acute Respiratory and Emerging Infections Consortium WHO Clinical Characterisation Protocol UK study. Comprehensive demographic, clinical, and outcome data were collected prospectively up to 28 days post discharge.

Results

A coinfecting virus was detected in 20 (2.0%) participants. Multivariable analysis revealed no significant risk factors for coinfection, although this may be due to rarity of coinfection. Likewise, ordinal logistic regression analysis did not demonstrate a significant association between coinfection and increased disease severity.

Conclusions

Viral coinfection was rare among hospitalized COVID-19 patients in the United Kingdom during the first 18 months of the pandemic. With unbiased prospective sampling, we found no evidence of an association between viral coinfection and disease severity. Public health interventions disrupted normal seasonal transmission of respiratory viruses; relaxation of these measures mean it will be important to monitor the prevalence and impact of respiratory viral coinfections going forward.

Co-existence and co-infection of influenza A viruses and coronaviruses: Public health challenges

Since the 20th century, humans have lived through five pandemics caused by influenza A viruses (IAVs) (H1N1/1918, H2N2/1957, H3N2/1968, and H1N1/2009) and the coronavirus (CoV) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). IAVs and CoVs both have broad host ranges and share multiple hosts. Virus co-circulation and even co-infections facilitate genetic reassortment among IAVs and recombination among CoVs, further altering virus evolution dynamics and generating novel variants with increased cross-species transmission risk. Moreover, SARS-CoV-2 may maintain long-term circulation in humans as seasonal IAVs. Co-existence and co-infection of both viruses in humans could alter disease transmission patterns and aggravate disease burden. Herein, we demonstrate how virus-host ecology correlates with the co-existence and co-infection of IAVs and/or CoVs, further affecting virus evolution and disease dynamics and burden, calling for active virus surveillance and countermeasures for future public health challenges.

A retrospective evaluation of multiple definitions for ventilator associated pneumonia (VAP) diagnosis in an Australian regional intensive care unit

BACKGROUND

Ventilator Associated Pneumonia is a common complication of invasively ventilated patients with significant and underestimated morbidity and mortality. Defining VAP cases is greatly varied as many definitions are used with varying success and sensitivity. This study evaluates VAP detection using four definitions in a regional Australian Intensive Care Unit (ICU).

METHODS

A cohort of patients admitted to ICU at the Mackay Base Hospital from April 1st 2020 to March 31st 2021, who had endo-tracheal intubation and mechanical ventilation for longer than 48 h were identified. Each patient was examined across four common definitions of VAP. Head-to-head analysis of definitions was pursued to determine the most suitable definition. The four definitions used included: An Australian VAP definition, the CDC VAP definition, the Mackay Base Hospital Local Protocol and a Physician Decision Arm.

RESULTS

66 unique patients and 2 re-intubations were identified during the data collection window. The local protocol identified 8 cases of VAP. The Australian VAP definition identified 6 additional cases and 0 missed cases compared to the local protocol. The CDC definition missed 4 cases and identified 4 additional cases compared to the local protocol. Finally, the physician arm identified 10 cases including 8 additional cases and missed 6 cases.

CONCLUSIONS

VAP is an extremely difficult clinical condition to define and detect. Definitions have varied accuracy and suffer logistically for application to the individual patient. Refined criteria for diagnosis of VAP is greatly needed and its prevalence in intensive care units likely remains uncertain.

How Drivers of Seasonality in Respiratory Infections May Impact Vaccine Strategy: A Case Study in How Coronavirus Disease 2019 (COVID-19) May Help Us Solve One of Influenza's Biggest Challenges

Vaccines against seasonal infections like influenza offer a recurring testbed, encompassing challenges in design, implementation, and uptake to combat a both familiar and ever-shifting threat. One of the pervading mysteries of influenza epidemiology is what causes the distinctive seasonal outbreak pattern. Proposed theories each suggest different paths forward in being able to tailor precision vaccines and/or deploy them most effectively. One of the greatest challenges in contrasting and supporting these theories is, of course, that there is no means by which to actually test them. In this communication we revisit theories and explore how the ongoing coronavirus disease 2019 (COVID-19) pandemic might provide a unique opportunity to better understand the global circulation of respiratory infections. We discuss how vaccine strategies may be targeted and improved by both isolating drivers and understanding the immunological consequences of seasonality, and how these insights about influenza vaccines may generalize to vaccines for other seasonal respiratory infections.

Trends in effectiveness of inactivated influenza vaccine in children by age groups in seven seasons immediately before the COVID-19 era

BACKGROUND

We have reported the vaccine effectiveness of inactivated influenza vaccine in children aged 6 months to 15 years between the 2013/14 and 2018/19 seasons. Younger (6-11 months) and older (6-15 years old) children tended to have lower vaccine effectiveness. The purpose of this study is to investigate whether the recent vaccine can be recommended to all age groups.

METHODS

The overall adjusted vaccine effectiveness was assessed from the 2013/14 until the 2020/21 season using a test-negative case-control design based on rapid influenza diagnostic test results. Vaccine effectiveness was calculated by influenza type and by age group (6-11 months, 1-2, 3-5, 6-12, and 13-15 years old) with adjustments including influenza seasons.

RESULTS

A total of 29,400 children (9347, 4435, and 15,618 for influenza A and B, and test-negatives, respectively) were enrolled. The overall vaccine effectiveness against influenza A, A(H1N1)pdm09, and B was significant (44% [95% confidence interval (CI), 41-47], 63% [95 %CI, 51-72], and 37% [95 %CI, 32-42], respectively). The vaccine was significantly effective against influenza A and B, except among children 6 to 11 months against influenza B. The age group with the highest vaccine effectiveness was 1 to 2 years old with both influenza A and B (60% [95 %CI, 55-65] and 52% [95 %CI, 41-61], respectively). Analysis for the 2020/21 season was not performed because no cases were reported.

CONCLUSIONS

This is the first report showing influenza vaccine effectiveness by age group in children for several seasons, including immediately before the coronavirus disease (COVID-19) era. The fact that significant vaccine effectiveness was observed in nearly every age group and every season shows that the recent vaccine can still be recommended to children for the upcoming influenza seasons, during and after the COVID-19 era.

Trends and Disparities in the Utilization of Influenza Vaccines Among Commercially Insured US Adults During the COVID-19 Pandemic

Objectives

Little is known about how the coronavirus disease 2019 (COVID-19) pandemic affected influenza vaccine utilization and disparities. We sought to estimate changes in the likelihood of receiving an influenza vaccine across different demographic subgroups during the COVID-19 pandemic.

Methods

In this cohort study, we analyzed influenza vaccine uptake from 2019 to 2020 using Optum commercial insurance claims data. Eligible individuals were aged 18 or above in 2018 and continuously enrolled from 08/01/2018 through 12/31/2020. Multivariable logistic regressions were fitted for the individual-level influenza vaccine uptake. Adjusting for demographic factors and medical histories, we estimated probabilities of receiving influenza vaccines before and after the COVID-19 pandemic across demographic subgroups.

Results

From August to December 2019, unadjusted influenza vaccination rate was 42.3%, while in the same period of 2020, the vaccination rate increased to 45.9%. Females had a higher vaccination rate in 2019 (OR: 1.16, 95% CI 1.15–1.16), but the increase was larger for males. Blacks and Hispanics had lower vaccination rates relative to whites in both flu seasons. Hispanics showed a greater increase in vaccination rate, increasing by 7.8 percentage points (p < .001) compared to 4.4 (p < .001) for whites. The vaccination rate for Blacks increased by 5.2 percentage points (p < .001). All income groups experienced vaccination improvements, but poorer individuals had lower vaccination rates in both seasons. The most profound disparities occurred when educational cohort were considered. The vaccination rate increased among college-educated enrollees by 8.8 percentage points (p < .001) during the pandemic compared to an increase of 2.8 percentage points (p < .001) for enrollees with less than a 12th grade education. Past influenza infections or vaccination increased the likelihood of vaccination (p < .001).

Conclusions

The COVID-19 pandemic was associated with increased influenza vaccine utilization. Disparities persisted but narrowed with respect to gender and race but worsened with respect to income and educational attainment.

Influenza Vaccination Uptake in the General Italian Population during the 2020–2021 Flu Season: Data from the EPICOVID-19 Online Web-Based Survey

To assess influenza vaccine uptake during the 2020/2021 flu season and compare it with that of the 2019/2020 flu season among respondents to the second phase of the web-based EPICOVID-19 survey, we performed an observational web-based nationwide online survey (January–February 2021) in which respondents to the first survey (April–June 2020) were contacted and asked to complete a second questionnaire. Factors associated with vaccine uptake in the 2020/2021 flu season were assessed by applying a multivariable multinomial logistic regression model. Out of the 198,822 respondents to the first survey, 41,473 (20.9%) agreed to fill out the follow-up questionnaire; of these, 8339 (20.1%) were vaccinated only during the 2020/2021 season, 8828 (21.3%) were vaccinated during both seasons and 22,710 (54.8%) were vaccinated in neither season. Educational level (medium (aOR 1.33 95%CI 1.13–1.56) and high (aOR 1.69 95%CI 1.44–1.97) vs. low) and socio-economic deprivation according to SES scoring (1 point aOR 0.83 (95%CI 0.78–0.89), 2 aOR 0.68 (95%CI 0.60–0.77) points or ≥3 points aOR 0.42 (95%CI 0.28–0.45) vs. 0 points) were found to be associated with flu vaccine uptake. Our study shows that social determinants seemed to affect flu vaccination uptake and identifies specific categories of the population to target during future influenza vaccination campaigns.

The Influence of COVID-19 on Influenza and Respiratory Syncytial Virus Activities

Background: Respiratory viral diseases have considerably declined since the COVID-19 outbreak, perhaps through influence by nonpharmaceutical interventions. We conducted a cross-sectional study using the CDC database to compare the pre- vs. post-pandemic flu activity (incidence) between the US states. Our secondary objectives were to estimate the association between flu activity and flu vaccination rates and compare the national trends of flu and RSV activities since the pandemic outbreak. Methods: We estimated the difference between pre-pandemic (April 2019–March 2020) and post-pandemic (April 2020–March 2021) flu activity between individual states using the Wilcoxon signed-rank test. The association between flu activity and immunization rates was also measured. Finally, parallel time trend graphs for flu and RSV activities were illustrated with a time series modeler. Results: The median (IQR) pre-pandemic flu activity was 4.10 (1.38), higher than the post-pandemic activity (1.38 (0.71)) (p-value < 0.001). There was no difference between pre-pandemic (45.50% (39.10%)) and post-pandemic (45.0% (19.84%)) flu vaccine acceptance (p-value > 0.05). Flu activity and vaccination rates were not associated (p-value > 0.05). Flu activity has declined since the COVID-19 outbreak, while RSV made a strong comeback in June 2021. Conclusion: Flu activity has significantly diminished throughout the pandemic while a sudden upsurge in RSV is a public health concern indicative of possible resurgence of other viruses. Flu vaccine acceptance neither changed during the pandemic nor influenced the diminished Flu activity.

Different Circulation Pattern of Multiple Respiratory Viruses in Southern China During the COVID-19 Pandemic

China implemented stringent non-pharmaceutical interventions (NPIs) in spring 2020, which has effectively suppressed SARS-CoV-2. In this study, we utilized data from routine respiratory virus testing requests from physicians and examined circulation of 11 other respiratory viruses in Southern China, from January 1, 2018 to December 31, 2020. A total of 58,169 throat swabs from patients with acute respiratory tract infections (ARTIs) were collected and tested. We found that while the overall activity of respiratory viruses was lower during the period with stringent NPIs, virus activity rebounded shortly after the NPIs were relaxed and social activities resumed. Only influenza was effectively suppressed with very low circulation which extended to the end of 2020. Circulation of other respiratory viruses in the community was maintained even during the period of stringent interventions, especially for rhinovirus. Our study shows that NPIs against COVID-19 have different impacts on respiratory viruses.

Systematic review with meta-analysis of diagnostic test accuracy for COVID-19 by mass spectrometry

BACKGROUND

The global COVID-19 pandemic has led to extensive development in many fields, including the diagnosis of COVID-19 infection by mass spectrometry. The aim of this systematic review and meta-analysis was to assess the accuracy of mass spectrometry diagnostic tests developed so far, across a wide range of biological matrices, and additionally to assess risks of bias and applicability in studies published to date.

METHOD

23 retrospective observational cohort studies were included in the systematic review using the PRISMA-DTA framework, with a total of 2858 COVID-19 positive participants and 2544 controls. Risks of bias and applicability were assessed via a QUADAS-2 questionnaire. A meta-analysis was also performed focusing on sensitivity, specificity, diagnostic accuracy and Youden's Index, in addition to assessing heterogeneity.

FINDINGS

Sensitivity averaged 0.87 in the studies reviewed herein (interquartile range 0.81-0.96) and specificity 0.88 (interquartile range 0.82-0.98), with an area under the receiver operating characteristic summary curve of 0.93. By subgroup, the best diagnostic results were achieved by viral proteomic analyses of nasopharyngeal swabs and metabolomic analyses of plasma and serum. The performance of other sampling matrices (breath, sebum, saliva) was less good, indicating that these protocols are currently insufficiently mature for clinical application.

CONCLUSIONS

This systematic review and meta-analysis demonstrates the potential for mass spectrometry and 'omics in achieving accurate test results for COVID-19 diagnosis, but also highlights the need for further work to optimize and harmonize practice across laboratories before these methods can be translated to clinical applications.

Epidemiological and Virological Surveillance of Seasonal Influenza Viruses - China, 2020-2021

INTRODUCTION

During the coronavirus disease 2019 (COVID-19) pandemic, the circulation of seasonal influenza virus declined globally and remained below previous seasonal levels. We analyzed the results of the epidemiology, antigenic, and genetic characteristics, and antiviral susceptibilities of seasonal influenza viruses isolated from the mainland of China during October 5, 2020 through September 5, 2021, to better assess the risk of influenza during subsequent influenza season in 2021-2022.

METHODS

Positive rates of influenza virus detection during this period were based on real-time polymerase chain reaction (PCR) detection by the Chinese National Influenza Surveillance Network laboratories, and isolated viruses from influenza positive samples were submitted to the Chinese National Influenza Center. Antigenic analyses for influenza viruses were conducted using the hemagglutination inhibition assay. Next-generation sequencing was used for genetic analyses. Viruses were tested for resistance to antiviral medications using a phenotypic assay and next-generation sequencing.

RESULTS

In southern China, the influenza positivity rate was elevated especially after March 2021 and was higher than the same period the previous year with the COVID-19 pandemic. In northern China, influenza positive rate peaked at Week 18 in 2021 and has declined since then. Nearly all isolated viruses were B/Victoria lineage viruses during the study period, and 37.3% of these viruses are antigenically similar to the reference viruses representing the vaccine components for the 2020-2021 and 2021-2022 Northern Hemisphere influenza season. All seasonal influenza viruses were susceptible to neuraminidase inhibitors and endonuclease inhibitors.

CONCLUSIONS

Influenza activity has gradually increased in the mainland of China in 2021, although the intensity of activity is still lower than before the COVID-19 pandemic. The diversity of circulating influenza types/subtypes decreased, with the vast majority being B/Victoria lineage viruses. The surveillance data from this study suggest that we should strengthen influenza surveillance during the upcoming traditional influenza season. It also provided evidence for vaccine recommendations and prevention and control of influenza and clinical use of antiviral drugs.

DYNAMICS OF CHILDHOOD RESPIRATORY INFECTIONS DURING THE COVID-19 PANDEMIC: THE EFFECT OF QUARANTINE АND BEYOND

Monitoring epidemic processes and the dynamics of the spread of infectious diseases is essential for predicting their distribution and effective planning in healthcare. The importance of studying seasonal trends in the spread of respiratory viral infections and the specific effects of non-pharmaceutical interventions in nationwide scales and the use of available vaccines stand out even more in the context of the coronavirus disease-19 (COVID-19) pandemic. Even if the dynamics of pediatric respiratory viral infections show some variation at the national and local levels, depending on health regulation, respiratory viral pathogens follow a typical pattern of incidence. Therefore, we hypothesize that anticipated reduction of the incidence of common respiratory viral infections would undoubtedly exert positive effects, such as ease of burdening healthcare that combates the COVID-19 pandemic. However, we suspect a shift in familiar seasonal characteristics of common respiratory viral infections. We also speculate that strict long-term limitations of the natural spread of respiratory viral infections can lead to the development of hard-to-predict epidemiological outliers. Additionally, the tricky balance between humanity’s natural impulse to return to normalcy and control the new and still dynamically evolving infection could lead to new threats from old and well-known pathogens. Finally, we hypothesize that the absence of regular influenza virus circulation may lead to a high mismatch rate and a significant reduction in flu vaccine efficacy.