Seasonal Coronaviruses and Other Neglected Respiratory Viruses: A Global Perspective and a Local Snapshot

Rhinovirus infection and co-infection in children with severe acute respiratory infection during the COVID-19 pandemic period

Rhinovirus causes respiratory tract infections in children and is found in co-infections. The objective of this research was to study the clinical profile of rhinovirus infection and co-infection in children with severe acute respiratory infection (SARI) during the COVID-19 pandemic period. We included 606 children ranging in age from 0.1 to 144 months of age from March 2020 to December 2021, hospitalized in the Pediatric Intensive Care Unit (PICU). The samples were collected by secretion from the nasopharynx region. A total of 259 children were tested positive for viral infection, 153 (59.07%) of them had a single rhinovirus infection and, 56 (36.6%) were aged between 60.1 and 144 months. Nine types of co-infections were identified and were found coinfection with three or more viruses (22/104, 21.15%). Observing the seasonality, the number of cases was similar between 2020 (49.53%) and 2021 (51.47%). Patients with a single infection (86.88%) and coinfection (67.30%) were more likely to have coughed. Patients with co-infection required the use of O2 for longer than those with a single rhinovirus infection. Hemogram results obtained from individuals with a single infection had higher levels of urea when compared to patients with co-infection with and other respiratory viruses. Multiple correspondence analyses indicated different clinical symptoms and comorbidities in patients with co-infection compared to those with single infection. The results found that the rhinovirus was much prevalent virus during the pandemic period and was found in co-infection with other virus types, what is important to diagnostic for the correct treatment of patients.

Polyoxometalate exerts broad-spectrum activity against human respiratory viruses hampering viral entry

Human respiratory viruses have an enormous impact on national health systems, societies, and economy due to the rapid airborne transmission and epidemic spread of such pathogens, while effective specific antiviral drugs to counteract infections are still lacking. Here, we identified two Keggin-type polyoxometalates (POMs), [TiW11CoO40]8- (TiW11Co) and [Ti2PW10O40]7- (Ti2PW10), endowed with broad-spectrum activity against enveloped and non-enveloped human respiratory viruses, i.e., coronavirus (HCoV-OC43), rhinovirus (HRV-A1), respiratory syncytial virus (RSV-A2), and adenovirus (AdV-5). Ti2PW10 showed highly favorable selectivity indexes against all tested viruses (SIs >700), and its antiviral potential was further investigated against human coronaviruses and rhinoviruses. This POM was found to inhibit replication of multiple HCoV and HRV strains, in different cell systems. Ti2PW10 did not affect virus binding or intracellular viral replication, but selectively inhibited the viral entry. Serial passaging of virus in presence of the POM revealed a high barrier to development of Ti2PW10-resistant variants of HRV-A1 or HCoV-OC43. Moreover, Ti2PW10 was able to inhibit HRV-A1 production in a 3D model of the human nasal epithelium and, importantly, the antiviral treatment did not determine cytotoxicity or tissue damage. A mucoadhesive thermosensitive in situ hydrogel formulation for nasal delivery was also developed for Ti2PW10. Overall, good biocompatibility on cell lines and human nasal epithelia, broad-spectrum activity, and absence of antiviral resistance development reveal the potential of Ti2PW10 as an antiviral candidate for the development of a treatment of acute respiratory viral diseases, warranting further studies to identify the specific target/s of the polyanion and assess its clinical potential.

Epidemiology of Respiratory Viruses in Korean Children Before and After the COVID-19 Pandemic: A Prospective Study From National Surveillance System

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic led to a decrease in the seasonal incidence of many respiratory viruses worldwide due to the impact of nonpharmaceutical interventions (NPIs). However, as NPI measures were relaxed, respiratory viral infections re-emerged. We aimed to characterize the epidemiology of respiratory viruses in Korean children during post-COVID-19 pandemic years compared to that before the pandemic.

METHODS

A nationwide prospective ongoing surveillance study has been conducted for detection of respiratory viruses between January 2017 and June 2023. We included data on adenovirus (AdV), human bocavirus (HBoV), human coronavirus (HCoV), human metapneumovirus (HMPV), human rhinovirus (HRV), influenza virus (IFV), parainfluenza virus (PIV), and respiratory syncytial virus (RSV), which were detected in children and adolescents younger than 20 years. We analyzed the weekly detection frequency of individual viruses and the age distribution of the affected children. The study period was divided into prepandemic (2017-2019) and postpandemic (2021-2023) periods.

RESULTS

A total of 19,589 and 14,068 samples were collected in the pre- and postpandemic periods, respectively. The overall detection rate of any virus throughout the study period was 63.1%, with the lowest occurring in the 2nd half of 2020 (50.6%) and the highest occurring in the 2nd half of 2021 (72.3%). Enveloped viruses (HCoV, HMPV, IFV, PIV, and RSV) almost disappeared, but nonenveloped viruses (AdV, HBoV, and HRV) were detected even during the peak of the COVID-19 pandemic. The codetection rate increased from 15.0% prepandemic to 19.1% postpandemic (P < 0.001). During the postpandemic period, a large out-of-season PIV and HMPV epidemic occurred, but the usual seasonality began to be restored in 2023. The mean age of children with each virus detected in 2023 was significantly greater than that in prepandemic years (P = 0.003 and 0.007 for AdV and HCoV, respectively; P < 0.001 for others). The mean age of children with IFV increased in 2022 (11.1 ± 5.2 years) from prepandemic years (7.9 ± 4.6 years) but decreased to 8.7 ± 4.1 years in 2023.

CONCLUSION

With the relaxation of NPI measures, several seasonal respiratory viruses cocirculated with unusual seasonal epidemic patterns and were associated with increasing age of infected children.

Prevalence and clinical impact of mono- and co-infections with endemic coronaviruses 229E, OC43, NL63, and HKU-1 during the COVID-19 pandemic

Introduction

Endemic human coronaviruses (eHCoVs) are found worldwide and usually result in mild to moderate upper respiratory tract infections. They can lead to more severe illnesses such as croup, bronchiolitis, and pneumonia in vulnerable populations. During the coronavirus disease 2019 (COVID-19) pandemic, information on HCoV prevalence and incidence and clinical impact of co-infections of HCoV with SARS-CoV-2 was lacking.

Objectives

Thus, this study aimed to determine the prevalence and clinical significance of infections caused by eHCoVs during the COVID-19 pandemic in Bulgaria.

Methods

From January 2021 to December 2022, nasopharyngeal swabs of patients with acute upper or lower respiratory tract infections were tested for 17 respiratory viruses using multiplex real-time polymerase chain reaction assays. The clinical data and laboratory parameters of patients infected with respiratory viruses were analysed.

Results

Of the 1375 patients screened, 24 (1.7 %) were positive for HCoVs, and 197 (14.3 %) were positive for eight other seasonal respiratory viruses. Five (0.7 %) of 740 patients positive for SARS-CoV-2 were co-infected with eHCoVs. Co-infected patients had a mean C-reactive protein level of 198.5 ± 2.12 mg/mL and a mean oxygen saturation of 82 ± 2.8 mmHg, while those in patients co-infected with SARS-CoV-2 and other respiratory viruses were 61.8 mg/mL and 92.8 ± 4.6 mmHg, respectively (p < 0.05). Pneumonia was diagnosed in 63.3 % of patients with HCoV infection and 6 % of patients positive for other seasonal respiratory viruses (p < 0.05). Patients with SARS-CoV-2 mono-infection stayed in hospital for an average of 5.8 ± 3.7 days, whereas the average hospital stay of patients with eHCoV and SARS-CoV-2 co-infection was 9 ± 1.4 days (p < 0.05).

Conclusion

These findings indicate the low prevalence of eHCoVs and low co-infection rate between eHCoVs and SARS-CoV-2 during the COVID-19 pandemic in Bulgaria. Despite their low incidence, such mixed infections can cause severe signs that require oxygen therapy and longer hospital stays, underlining the need for targeted testing of severe COVID-19 cases to identify potential co-infections.

Design, synthesis, and biological evaluation of first-in-class indomethacin-based PROTACs degrading SARS-CoV-2 main protease and with broad-spectrum antiviral activity

To date, Proteolysis Targeting Chimera (PROTAC) technology has been successfully applied to mediate proteasomal-induced degradation of several pharmaceutical targets mainly related to oncology, immune disorders, and neurodegenerative diseases. On the other hand, its exploitation in the field of antiviral drug discovery is still in its infancy. Recently, we described two indomethacin (INM)-based PROTACs displaying broad-spectrum antiviral activity against coronaviruses. Here, we report the design, synthesis, and characterization of a novel series of INM-based PROTACs that recruit either Von-Hippel Lindau (VHL) or cereblon (CRBN) E3 ligases. The panel of INM-based PROTACs was also enlarged by varying the linker moiety. The antiviral activity resulted very susceptible to this modification, particularly for PROTACs hijacking VHL as E3 ligase, with one piperazine-based compound (PROTAC 6) showing potent anti-SARS-CoV-2 activity in infected human lung cells. Interestingly, degradation assays in both uninfected and virus-infected cells with the most promising PROTACs emerged so far (PROTACs 5 and 6) demonstrated that INM-PROTACs do not degrade human PGES-2 protein, as initially hypothesized, but induce the concentration-dependent degradation of SARS-CoV-2 main protease (Mpro) both in Mpro-transfected and in SARS-CoV-2-infected cells. Importantly, thanks to the target degradation, INM-PROTACs exhibited a considerable enhancement in antiviral activity with respect to indomethacin, with EC50 values in the low-micromolar/nanomolar range. Finally, kinetic solubility as well as metabolic and chemical stability were measured for PROTACs 5 and 6. Altogether, the identification of INM-based PROTACs as the first class of SARS-CoV-2 Mpro degraders demonstrating activity also in SARS-CoV-2-infected cells represents a significant advance in the development of effective, broad-spectrum anti-coronavirus strategies.

Viral Epitope Scanning Reveals Correlation between Seasonal HCoVs and SARS-CoV-2 Antibody Responses among Cancer and Non-Cancer Patients

Seasonal coronaviruses (HCoVs) are known to contribute to cross-reactive antibody (Ab) responses against SARS-CoV-2. While these responses are predictable due to the high homology between SARS-CoV-2 and other CoVs, the impact of these responses on susceptibility to SARS-CoV-2 infection in cancer patients is unclear. To investigate the influence of prior HCoV infection on anti-SARS-CoV-2 Ab responses among COVID-19 asymptomatic individuals with cancer and controls without cancers, we utilized the VirScan technology in which phage immunoprecipitation and sequencing (PhIP-seq) of longitudinal plasma samples was performed to investigate high-resolution (i.e., epitope level) humoral CoV responses. Despite testing positive for anti-SARS-CoV-2 Ab in the plasma, a majority of the participants were asymptomatic for COVID-19 with no prior history of COVID-19 diagnosis. Although the magnitudes of the anti-SARS-CoV-2 Ab responses were lower in individuals with Kaposi sarcoma (KS) compared to non-KS cancer individuals and those without cancer, the HCoV Ab repertoire was similar between individuals with and without cancer independent of age, sex, HIV status, and chemotherapy. The magnitudes of the anti-spike HCoV responses showed a strong positive association with those of the anti-SARS-CoV-2 spike in cancer patients, and only a weak association in non-cancer patients, suggesting that prior infection with HCoVs might play a role in limiting SARS-CoV-2 infection and COVID-19 disease severity.

The antiviral potential of the antiandrogen enzalutamide and the viral-androgen signaling interplay in seasonal coronaviruses

The sex disparity in COVID-19 outcomes with males generally faring worse than females has been associated with the androgen-regulated expression of the protease TMPRSS2 and the cell receptor ACE2 in the lung and fueled interest in antiandrogens as potential antivirals. In this study, we explored enzalutamide, an antiandrogen used commonly to treat prostate cancer, as a potential antiviral against the human coronaviruses which cause seasonal respiratory infections (HCoV-NL63, -229E, and -OC43). Using lentivirus-pseudotyped and authentic HCoV, we report that enzalutamide reduced 229E and NL63 entry and infection in both TMPRSS2- and nonexpressing immortalized cells, suggesting a TMPRSS2-independent mechanism. However, no effect was observed against OC43. To decipher this distinction, we performed RNA-sequencing analysis on 229E- and OC43-infected primary human airway cells. Our results show a significant induction of androgen-responsive genes by 229E compared to OC43 at 24 and 72 h postinfection. The virus-mediated effect on AR-signaling was further confirmed with a consensus androgen response element-driven luciferase assay in androgen-depleted MRC-5 cells. Specifically, 229E induced luciferase-reporter activity in the presence and absence of the synthetic androgen mibolerone, while OC43 inhibited induction. These findings highlight a complex interplay between viral infections and androgen-signaling, offering insights for disparities in viral outcomes and antiviral interventions.

Combined intravenous ribavirin and recombinant human interferon α1b aerosol inhalation for adenovirus pneumonia with plastic bronchitis in children: a case report and review of literature

Background

Human adenovirus (HAdV) infections in children can lead to profound pulmonary injury and are frequently associated with severe complications, particularly in cases concomitant with plastic bronchitis. Managing this condition presents significant challenges and carries an exceptionally high fatality rate. Regrettably, there are currently no specific antiviral agents that have demonstrated efficacy in treating severe adenovirus pneumonia in children.

Case presentation

We report a 10-month-old infant suffering from severe adenovirus pneumonia combined with plastic bronchitis (PB). He received intravenous ribavirin combined with recombinant human interferon α1b (INFα1b) aerosol inhalation and his condition eventually improved. No side effects occurred during the treatment, and the long-term prognosis was favorable.

Conclusion

In this case, the combination therapy of intravenous ribavirin and INFα1b seems to have contributed to the resolution of illness and may be considered for similar cases until stronger evidence is generated.

Rhinovirus dynamics across different social structures

Rhinoviruses (RV), common human respiratory viruses, exhibit significant antigenic diversity, yet their dynamics across distinct social structures remain poorly understood. Our study delves into RV dynamics within Kenya by analysing VP4/2 sequences across four different social structures: households, a public primary school, outpatient clinics in the Kilifi Health and Demographics Surveillance System (HDSS), and countrywide hospital admissions and outpatients. The study revealed the greatest diversity of RV infections at the countrywide level (114 types), followed by the Kilifi HDSS (78 types), the school (47 types), and households (40 types), cumulatively representing >90% of all known RV types. Notably, RV diversity correlated directly with the size of the population under observation, and several RV type variants occasionally fuelled RV infection waves. Our findings highlight the critical role of social structures in shaping RV dynamics, information that can be leveraged to enhance public health strategies. Future research should incorporate whole-genome analysis to understand fine-scale evolution across various social structures.

Significant reduction in the incidence of non-coronavirus infections in patients with chronic lymphocytic leukemia on ibrutinib and venetoclax treatment during the COVID-19 pandemic: An additional benefit of lockdown

Effective treatment and prevention of infections challenge management of patients with chronic lymphicytic leukemia (CLL). The COVID-19 pandemic resulted in the reduction of outpatient hospital visits as a part of non-pharmaceutical interventions that could affect the incidence of infectious complications. Study enrolled patients with CLL receiving ibrutinib or/and venetoclax who were observed at the Moscow City Centre of Hematology from 01 April 2017 to 31 March 2021. We found a reduction in the incidence of infectious episodes after the implementation of the lockdown in Moscow in 01 April 2020, when compared to data on the year prior to the lockdown (p < 0.0001), as well as when compared to the predictive model (p = 0.02), and based on individual infection profiles using cumulative sums (p < 0.0001). Bacterial infections had 4.44-fold decrease, bacterial in combination with undefined infections had 4.89-fold decrease, viral infections had unsignificant changes. The decrease in the number of outpatient visits coincides with the time of the lockdown could be a likely factor, explaining a decline in the incidence of infection. Patients were clustered according incidence and severity of infectious episodes for subgroup mortality assessment. No differences in overall survival due to COVID-19 were observed. Typical respiratory infections, bacterial and undefined, the transmission of which may be affected by patient-to-patient contact in the settings of out-patient health care visits were decreased, possibly due to SARS-CoV-2 restrictive measures. A positive correlation between outpatient visits and the incidence of bronchial and upper respiratory tract infection points at the role of hospital-acquired infection and attests to the necessity of reorganizing care for all patients with CLL.

Burden of respiratory syncytial virus in adults in the United Kingdom: A systematic literature review and gap analysis

Despite the growing recognition of a potentially significant respiratory syncytial virus (RSV) disease burden in adults, relevant evidence in the United Kingdom (UK) is limited. This systematic literature review (SLR) aimed to identify the disease burden of RSV in UK adults, including certain high-risk subgroups and existing evidence gaps. Published studies (2011 onwards) reporting epidemiological, economic and clinical burden outcomes in UK adults (≥15 years) with RSV were identified from indexed databases, including MEDLINE, Embase and the Cochrane library. High-risk groups included elderly (≥65 years), immunocompromised, co-morbid and co-infected patients. Outcomes included RSV incidence/prevalence, mortality, clinical presentation and direct/indirect resource use/costs. Twenty-eight publications on 28 unique studies were identified, mostly in general/respiratory indicator (n = 17), elderly (n = 10) and immunocompromised (n = 6) cohorts. Main outcomes reported in the general/respiratory indicator cohort were RSV infection incidence (seasonal/annual: 0.09-17.9%/6.6-15.1%), mortality (8,482 deaths/season) and direct resource use (including mean general practitioner [GP] episodes/season: 487,247). Seasonal/annual incidence was 14.6-26.5%/0.7-16% in high-risk cohorts. Attributed to RSV in the elderly were 7,915 deaths/season and 175,070 mean GP episodes/season. Only two studies reported on co-morbid cohorts. Clinical burden outcomes were only reported in general and immunocompromised patients, and no evidence was found in any cohort on indirect economic burden or RSV complications. Evidence captured suggests that RSV may have a substantial burden in UK adults. However, available data were limited and highly heterogenous, with further studies needed to characterise the burden of RSV in adults and to validate our findings.

Immunohematologic Biomarkers in COVID-19: Insights into Pathogenesis, Prognosis, and Prevention

Coronavirus disease 2019 (COVID-19) has had profound effects on the health of individuals and on healthcare systems worldwide. While healthcare workers on the frontlines have fought to quell multiple waves of infection, the efforts of the larger research community have changed the arch of this pandemic as well. This review will focus on biomarker discovery and other efforts to identify features that predict outcomes, and in so doing, identify possible effector and passenger mechanisms of adverse outcomes. Identifying measurable soluble factors, cell-types, and clinical parameters that predict a patient's disease course will have a legacy for the study of immunologic responses, especially stimuli, which induce an overactive, yet ineffectual immune system. As prognostic biomarkers were identified, some have served to represent pathways of therapeutic interest in clinical trials. The pandemic conditions have created urgency for accelerated target identification and validation. Collectively, these COVID-19 studies of biomarkers, disease outcomes, and therapeutic efficacy have revealed that immunologic systems and responses to stimuli are more heterogeneous than previously assumed. Understanding the genetic and acquired features that mediate divergent immunologic outcomes in response to this global exposure is ongoing and will ultimately improve our preparedness for future pandemics, as well as impact preventive approaches to other immunologic diseases.

The Impact of Coronavirus Disease 2019 on Viral, Bacterial, and Fungal Respiratory Infections

Although coronavirus disease 2019 (COVID-19) remains an ongoing threat, concerns regarding other respiratory infections remain. Throughout the COVID-19 pandemic various epidemiologic trends have been observed in other respiratory viruses including a reduction in influenza and respiratory syncytial virus infections following onset of the COVID-19 pandemic. Observations suggest that infections with other respiratory viruses were reduced with social distancing, mask wearing, eye protection, and hand hygiene practices. Coinfections with COVID-19 exist not only with other respiratory viruses but also with bacterial pneumonias and other nosocomial and opportunistic infections. Coinfections have been associated with increased severity of illness and other adverse outcomes.

The Burden of Human Bocavirus 1 in Hospitalized Children With Respiratory Tract Infections

BACKGROUND

Human bocavirus 1 (HBoV1) is frequently codetected with other viruses, and detected in asymptomatic children. Thus, the burden of HBoV1 respiratory tract infections (RTI) has been unknown. Using HBoV1-mRNA to indicate true HBoV1 RTI, we assessed the burden of HBoV1 in hospitalized children and the impact of viral codetections, compared with respiratory syncytial virus (RSV).

METHODS

Over 11 years, we enrolled 4879 children <16 years old admitted with RTI. Nasopharyngeal aspirates were analyzed with polymerase chain reaction for HBoV1-DNA, HBoV1-mRNA, and 19 other pathogens.

RESULTS

HBoV1-mRNA was detected in 2.7% (130/4850) samples, modestly peaking in autumn and winter. Forty-three percent with HBoV1 mRNA were 12-17 months old, and only 5% were <6 months old. A total of 73.8% had viral codetections. It was more likely to detect HBoV1-mRNA if HBoV1-DNA was detected alone (odds ratio [OR]: 3.9, 95% confidence interval [CI]: 1.7-8.9) or with 1 viral codetection (OR: 1.9, 95% CI: 1.1-3.3), compared to ≥2 codetections. Codetection of severe viruses like RSV had lower odds for HBoV1-mRNA (OR: 0.34, 95% CI: 0.19-0.61). The yearly lower RTI hospitalization rate per 1000 children <5 years was 0.7 for HBoV1-mRNA and 8.7 for RSV.

CONCLUSIONS

True HBoV1 RTI is most likely when HBoV1-DNA is detected alone, or with 1 codetected virus. Hospitalization due to HBoV1 LRTI is 10-12 times less common than RSV.

Coincidence of Candida Endophthalmitis, and Aspergillus and Pneumocystis jirovecii Pneumonia in a COVID-19 Patient: Case Report

INTRODUCTION

Coronavirus disease 2019 (COVID-19) is associated with immune system dysfunction and makes patients vulnerable to opportunistic infections. This report presents a patient with a history of COVID-19, suffering from opportunistic infections.

CASE DESCRIPTION

We reported a 64-year-old man complaining of progressive visual loss in his left eye, who had previously been hospitalized for three weeks due to COVID-19. In the ophthalmologic assessment, large foci of dense subretinal and intraretinal infiltrations involving the macula were observed (compatible with endogenous fungal endophthalmitis). Real-time PCR result of intraocular fluid was positive for Candida spp. During subsequent hospitalization, the patient also suffered from fever and productive coughs (manifestations of pneumonia caused by Aspergillus fumigatus and Pneumocystis jirovecii). In response to antibiotic therapy, the fever and coughs subsided, and the ocular examination revealed a dramatic decrease in the size of retinal infiltrations.

CONCLUSIONS

In patients with severe COVID-19, long-term ICU admission and immunosuppressive drugs lead to immune system dysfunction and make the patient more susceptible to opportunistic infections. Consequently, fungal pathogens such as Aspergillus, Pneumocystis jirovecii, and Candida spp. may cause infection in different body organs. Thus, clinicians should be alert and have clinical suspicion to diagnose accurately and manage patients accordingly.

Spread of Pathogens Causing Respiratory Viral Diseases Before and During CoVID-19 Pandemic in Kazakhstan

Analyze clinical samples collected and determine the etiology of viral pathogens and the dynamics of their spread. Acute respiratory viral infections remain one of the key health problems worldwide. They constitute etiologically independent diseases, with similar clinical infection manifestations and a single mechanism for the transmission of pathogens. 4712 nasopharyngeal swabs were collected from people before and during the COVID-19 pandemic with acute respiratory infections that tested negative for COVID-19 and were examined in this study. The collected samples were screened by a real-time polymerase chain reaction on a Rotor-Gene Q6 plex instrument. Statistical processing of the results, tabular, and graphical data were analyzed in the MS Excel. The largest number of the nasopharyngeal swabs were collected from children under 17 years of age (60.75%). In 702 samples (9.85%) pathogens of respiratory infections of non-influenza etiology were detected, including adenovirus, bocavirus, coronavirus, metapneumovirus, paramyxovirus types I–IV, respiratory syncytial virus, and rhinovirus. At the same time, both before and during the COVID-19 pandemic, different influenza virus variants co-circulation (A/H1N1, A/H3N2, and type B) were discovered, with a predominance of viruses with the antigenic formula A/H1N1. The results of the study indicate the need for continuous monitoring of the viral pathogens spread, which will expand the existing knowledge of the viral etiology of respiratory diseases and highlight the importance of viruses in the respiratory infections occurrence.

Reduced Seasonal Coronavirus Antibody Responses in Children Following COVID-19 Mitigation Measures, The Netherlands

SARS-CoV-2 prevention and control measures did not only impact SARS-CoV-2 circulation, but also the timing and prevalence of other seasonal respiratory viruses. Especially in children, information on exposure and infections to seasonal coronaviruses as well as SARS-CoV-2 in the first year of the pandemic is largely lacking. Therefore, we set up a one-year serological survey in a large tertiary hospital in the Netherlands. We show that seasonal coronavirus seroprevalence significantly decreased in 2021 in children less than one year, most likely due to COVID-19 control measures. The SARS-CoV-2 seroprevalence in children and adolescents increased from 0.4% to 11.3%, the highest in adolescents. This implies higher exposure rates in adolescents as compared to the general population (>18 years old). It is clear that there have been significant changes in the circulation and subsequent immunity against most respiratory pathogens as a result of the mitigation measures. The implications on shorter as well as longer term are still largely unknown, but the impact of the SARS-CoV-2 pandemic and subsequent control measures will continue to affect the dynamics of other pathogens.

The Prevalence of COVID-19 in Europe by the End of November 2022: A Cross-Sectional Study

Background The world has been affected differently by the coronavirus disease 2019 (COVID-19), and Europe reaped the largest number of cases and deaths. Moreover, COVID-19 statistics are dynamic. Objectives The current study aimed to use COVID-19 data to examine the COVID-19 prevalence in Europe by the end of November 2022 and compare the findings globally. Methods The primary data on COVID-19 for each European country were obtained from the "Worldometer" website. The data include the cumulative incidence of COVID-19 per country, the cumulative number of deaths, the total number of tests performed, the number of cases per million population, the number of deaths per million, the number of tests per million, and the total population. The case-fatality rate was calculated (number of deaths/number of cases). In addition, the median age and the vaccination coverage rate (people who received two doses) for each European country were extracted from the "United Nations" website and the "Our World in Data" website, respectively. To compare European countries to the globe, COVID-19 data for each continent were obtained. The analysis of variance (ANOVA) test was used to compare variances across the means of the four parts of Europe based on the geographic division. An independent sample t-test was also used to compare the means between the European Union (EU) states and non-EU states. The Spearman correlation coefficient was used to determine the relationship between different variables across Europe. Results As of December 1, 2022, about 648 million COVID-19 cases and 6.6 million deaths have been recorded worldwide. Europe accounted for nearly 36.8% and 29.5% of all cases and deaths, respectively. Based on the number of deaths per million, Europe was the most affected continent after South America. Nearly 6.8 billion tests have been conducted worldwide, 41% done in Europe; 43 European countries have performed tests more than their population. However, COVID-19 statistics were inconsistent across the four parts of Europe. A significant difference was noticed between Eastern Europe and others, especially Northern Europe and Western Europe. By affiliation with the EU, there was no significant difference. For global comparison, the mean deaths per million, the mean cases per million, and the mean tests per population for European countries were higher than those of the world's countries, although they recorded a lower mean case-fatality rate (CFR). Thirteen European countries were among the 15 most affected countries worldwide based on the number of deaths per million, most located in Eastern and Southern Europe. The number of cases and the number of deaths were significantly proportional to the number of tests performed. Conclusions By the end of November 2022, Europe had the most cases of COVID-19, the most deaths, and the most tests performed, even though it accounts for 9.4% of the world's population. However, COVID-19 data were inconsistent across the four parts of Europe, especially between Eastern Europe and others. Given the natural immunity acquired during the three years and the excellent vaccine coverage in Europe, it is essential to reconsider the definition of a suspected case and establish more specific criteria for testing.

Etiologies of outpatient medically attended acute respiratory infections among young Ecuadorian children prior to the start of the 2020 SARS-CoV-2 pandemic

BACKGROUND

Implementation of respiratory virus prevention measures requires detailed understanding of regional epidemiology; however, data from many tropical countries are sparse. We describe etiologies of ambulatory pediatric acute respiratory tract infections (ARTI) in Ecuador immediately preceding the onset of the SARS-CoV-2 pandemic.

METHODS

Children < 5 years presenting to a designated study site with an ARTI were eligible. Informed consent was obtained. Demographic and clinical data were recorded. A nasopharyngeal swab was collected, processed, and analyzed using multiplex polymerase chain reaction (PCR) for common respiratory pathogens. Rhinovirus/enterovirus positive samples were further characterized by genomic sequencing.

RESULTS

A total of 820 subjects were enrolled in the study between July 2018 and March 2020. A total of 655 (80%) samples identified at least one pathogen. Rhinoviruses (44%) were most common, followed by enteroviruses (17%), parainfluenza viruses (17%), respiratory syncytial virus (RSV) (15%), and influenza viruses (13%). Enterovirus D68 was the most common enterovirus detected and was among the leading causes of bronchiolitis. Seasonal RSV and influenza virus activity were different along the coast compared with the highlands.

CONCLUSIONS

Ongoing regional surveillance studies are necessary to optimize available and emerging pathogen-specific preventative measures.

Comprehensive role of SARS-CoV-2 spike glycoprotein in regulating host signaling pathway

Since the outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, global public health and the economy have suffered unprecedented damage. Based on the increasing related literature, the characteristics and pathogenic mechanisms of the virus, and epidemiological and clinical features of the disease are being rapidly discovered. The spike glycoprotein (S protein), as a key antigen of SARS-CoV-2 for developing vaccines, antibodies, and drug targets, has been shown to play an important role in viral entry, tissue tropism, and pathogenesis. In this review, we summarize the molecular mechanisms of interaction between S protein and host factors, especially receptor-mediated viral modulation of host signaling pathways, and highlight the progression of potential therapeutic targets, prophylactic and therapeutic agents for prevention and treatment of SARS-CoV-2 infection.

Immunodetection assays for the quantification of seasonal common cold coronaviruses OC43, NL63, or 229E infection confirm nirmatrelvir as broad coronavirus inhibitor

Besides pandemic SARS-CoV-2, also endemic seasonal human common cold coronaviruses (hCoVs) have a significant impact on human health and economy. Studies on hCoVs and the identification of antivirals are therefore crucial to improve human well-being. However, hCoVs have long been neglected and the methodology to study virus infection, replication and inhibition warrants being updated. We here evaluated the established plaque-based assays to determine viral titers and cell-to-cell spread and developed protocols for the immunodetection of the viral nucleocapsid protein by flow cytometry and in-cell ELISA to study infection rates at early time points. The developed protocols allow detection of hCoV-229E infection after 2, and hCoV-NL63 and -OC43 infection after 3 days at a single cell level or in a 96 well microtiter format, in large sample numbers without being laborious or expensive. Both assays can be applied to assess the susceptibility of cells to hCoV infection and replication, and to determine the efficacy of antiviral compounds as well as neutralizing antibodies in a sensitive and quantitative manner. Application revealed that clinically applied SARS-CoV-2 targeting monoclonal antibodies are inactive against hCoVs, but that the viral polymerase targeting antivirals remdesivir and molnupiravir are broadly active also against all three hCoVs. Further, the in-cell ELISA provided evidence that nirmatrelvir, previously shown to broadly inhibit coronavirus proteases, also prevents replication of authentic hCoVs. Importantly, the protocols described here can be easily adapted to other coronavirus strains and species as well as viruses of other families within a short time. This will facilitate future research on known and emerging (corona)viruses, support the identification of antivirals and increase the preparedness for future virus outbreaks.

Changes in the pattern and disease burden of acute viral respiratory infections before and during the COVID-19 pandemic

Objectives

We conducted a comparative analysis of the differences in the incidence of 8 acute respiratory viruses and the changes in their patterns before and during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

Three sentinel surveillance systems of the Korea Disease Control and Prevention Agency and data from the Health Insurance Review and Assessment Service were analyzed. The average numbers of reported cases and the related hospital admissions and outpatient data were compared between April 2018–2019 and 2020–2021. Changes in the disease burden and medical expenditures between these 2 time periods were evaluated.

Results

During the COVID-19 pandemic, the number of reported cases of all acute respiratory viral infections, except for human bocavirus, decreased significantly. Data from the Health Insurance Review and Assessment Service also showed decreases in the actual amount of medical service usage and a marked reduction in medical expenditures.

Conclusion

Non-pharmacological interventions in response to COVID-19 showed preventive effects on the transmission of other respiratory viruses, as well as COVID-19. Although COVID-19 had a tremendous impact on society as a whole, with high social costs, there were also positive effects, such as a reduction in the incidence of acute respiratory viral infections.