Global prevalence of respiratory virus infections in adults and adolescents during the COVID-19 pandemic: A systematic review and meta-analysis

Human metapneumovirus (hMPV) in 2025: emerging trends and insights from community and hospital-based respiratory panel analyses-a comprehensive review

Human metapneumovirus (hMPV) is a significant respiratory pathogen, primarily impacting young, elderly, and immunocompromised populations. While the clinical presentations are similar to those of other respiratory viruses such as respiratory syncytial virus (RSV), influenza, and SARS-CoV-2, they can still lead to serious complications. The virus primarily transmits via respiratory droplets, with outbreaks peaking during winter and spring. In resource-limited settings, administration of multiplex PCR assays is essential for precise diagnosis, yet it presents significant challenges. Recent studies indicate a 6.24% infection rate in hospitalized patients presenting with acute respiratory infections (ARIs). Enhanced surveillance and prevention are essential given the morbidity and mortality rates of hMPV, which are comparable to those of influenza and RSV. Effective management requires enhanced diagnostic tools, improved public health strategies, and continuous research into antiviral therapies and vaccines. This study highlighted the growing importance of hMPV as a respiratory pathogen, focusing on its seasonal patterns, clinical manifestations in at-risk populations, transmission dynamics, and diagnostic challenges compared to other respiratory viruses.

Influenza epidemiology and co-infections within New South Wales-based multicentre health districts between 2018 and 2023

Influenza epidemiology spanning pre-COVID-19 pandemic to post-COVID-19 pandemic periods in Australia is insufficiently described. This study reviewed influenza epidemiology in two metropolitan New South Wales (NSW) health districts between 2018 and 2023 and investigated influenza virus (IFV) co-infections with other respiratory viruses (ORVs). A retrospective analysis of diagnostic polymerase chain reaction data from patients requiring testing for IFV and/or ORVs was conducted. Influenza detections were exceptionally low (n=57, <0.2% positivity) between April 2020 and 2021 when compared to those in 2019 (n=3,312, 14.4% positivity). Subsequent relaxation of public health measures corresponded with increased positivity rates: from 0.1% (33) in 2021 to 2.1% (4,028) in 2022 and 3.8% (4,362) in 2023. Influenza A virus (IAV) activity peaked earlier in 2022 and 2023 compared to most prepandemic years. Influenza B virus (IBV) detections were notably higher in 2019 and 2023. Co-infections were identified in 17.2% (346/2010) of IFV-positive samples, with rhinovirus being the most frequent co-infecting virus (7.4%). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was only detected in 1.3% of IFV infections. Logistic regression revealed significantly higher odds of IFV co-infections in children aged under 5 years [odds ratio (OR) 8.18; 95% confidence interval (CI) 5.44-12.29; p<0.01] and in those aged 5-17 years (OR 2.45; 95% CI 1.59-3.77; p<0.01). A significant increase in the likelihood of IFV co-infection was also observed in 2022 (OR 2.42; 95% CI 1.23-4.75; p<0.05). This study described influenza epidemiology across pre-COVID-19 pandemic, during-COVID-19 pandemic, and post-COVID-19 pandemic periods in NSW. Key findings include the earlier IAV peak activity in 2022-2023 and a rapid increase in IBV detection rate from 2022 to 2023, underscoring the need for sustained influenza surveillance to monitor the persistence of these trends. The surge in influenza detections in 2022-2023, accompanied with increased testing volumes, suggests that future surveillance efforts should account for changes in rates of testing when assessing severity of influenza seasons. The higher IFV co-infection frequency was observed in children and adolescents. 'Flurona' cases remain infrequent and exclusively associated with IAVs. These insights also inform the future application of multiplex diagnostic methods.

Epidemiology, co-infection, and seasonal patterns of respiratory tract infections in a tertiary care center in Saudi Arabia between 2021 and 2022

Objectives

To investigate the etiology and epidemiological trends of respiratory tract infections (RTIs) during the COVID-19 pandemic in Saudi Arabia, focusing on age and seasonality.

Methods

We conducted a retrospective analysis of 19,509 respiratory specimens collected from January 2021 to December 2022 at King Abdulaziz Medical City, Riyadh, using the BioFire Filmarray Respiratory Panel 2.1 plus kit.

Results

Of the analyzed specimens, 53.3% (10,406) tested positive for at least one pathogen. Pediatric patients represented 72.5% of positive cases. Rhinovirus/enterovirus (32%) was the most prevalent, followed by SARS-CoV-2 (16%), respiratory syncytial virus (RSV; 13%), and adenovirus (10%).

Conclusions

The study underscores the significant seasonality and age-specific prevalence of RTIs, with winter peaks and a high incidence of rhinovirus/enterovirus, SARS-CoV-2, RSV, and adenovirus. These results emphasize the necessity of ongoing surveillance and targeted public health interventions to manage RTIs effectively.

Hidden in plain sight: the impact of human rhinovirus infection in adults

BACKGROUND

Human rhinovirus (HRV), a non-enveloped RNA virus, was first identified more than 70 years ago. It is highly infectious and easily transmitted through aerosols and direct contact. The advent of multiplex PCR has enhanced the detection of a diverse range of respiratory viruses, and HRV consistently ranks among the most prevalent respiratory pathogens globally. Circulation occurs throughout the year, with peak incidence in autumn and spring in temperate climates. Remarkably, during the SARS-CoV-2 pandemic, HRV transmission persisted, demonstrating its resistance to stringent public health measures aimed at curbing viral transmission.

MAIN BODY

HRV is characterised by its extensive genetic diversity, comprising three species and more than 170 genotypes. This diversity and substantial number of concurrently circulating strains allows HRVs to frequently escape the adaptive immune system and poses formidable challenges for the development of effective vaccines and antiviral therapies. There is currently a lack of specific treatments. Historically, HRV has been associated with self-limiting upper respiratory infection. However, there is now extensive evidence highlighting its significant role in severe lower respiratory disease in adults, including exacerbations of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD), as well as pneumonia. These severe manifestations can occur even in immunocompetent individuals, broadening the clinical impact of this ubiquitous virus. Consequently, the burden of rhinovirus infections extends across various healthcare settings, from primary care to general hospital wards and intensive care units. The impact of HRV in adults, in terms of morbidity and healthcare utilisation, rivals that of the other major respiratory viruses, including influenza and respiratory syncytial virus. Recognition of this substantial burden underscores the critical need for novel treatment strategies and effective management protocols to mitigate the impact of HRV infections on public health.

CONCLUSION

This review examines the epidemiology, clinical manifestations, and risk factors associated with severe HRV infection in adults. By drawing on contemporary literature, we aim to provide a comprehensive overview of the virus's significant health implications. Understanding the scope of this impact is essential for developing new, targeted interventions and improving patient outcomes in the face of this persistent and adaptable pathogen.

Risk of acute exacerbation of chronic obstructive pulmonary disease after COVID-19 recovery: a nationwide population-based cohort study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with severe Coronavirus disease 2019 (COVID-19) outcomes. However, it is uncertain whether the risk of acute exacerbation of COPD (AECOPD) increases after recovering from COVID-19.

METHODS

This study included 2,118 individuals with COPD from the Korea National Health Insurance Service database who were also diagnosed with COVID-19. Matched controls were chosen using 1:1 propensity score (PS) matching. We compared the risk of AECOPD after COVID-19 recovery between the COVID-19 cohort and matched controls between October 8, 2020, and December 31, 2021, using PS-matched Cox proportional hazard regression models.

RESULTS

During a median follow-up of 62 days (interquartile range, 29-179 days), including a median of 14 days of recovery time after COVID-19, 68 people (5.6%) in the COVID-19 cohort and 50 (3.9%) in the matched control group experienced AECOPD. Compared to the matched controls, the COVID-19 cohort had a significantly higher risk of overall AECOPD (hazard ratio [HR] = 1.45, 95% confidence interval [CI] = 1.09-1.92). This increased risk was particularly evident for severe AECOPD among individuals who had severe COVID-19 within the first 30days post-recovery (aHR = 8.14, 95% CI = 3.32-19.97). When classified by COVID-19 severity, while severe COVID-19 significantly increased this risk (aHR = 2.97, 95% CI = 2.15-4.11), non-severe COVID did not significantly influence the risk of AECOPD, regardless of time duration or exacerbation severity.

CONCLUSION

Individuals with COPD who had severe COVID-19 have increased risk of AECOPD after COVID-19 recovery, especially within the first 30 days after COVID-19 recovery.

Exploring the Preventive Potential of Solubilized Sturgeon Oil on Acute Infection with Respiratory Viruses

Acute respiratory viral infections (ARIs) represent a significant global health challenge, contributing heavily to worldwide morbidity and mortality rates. Recent efforts to combat ARIs have focused on developing nasal spray formulations that effectively target the nasal mucosa. However, challenges such as irritation, discomfort, and safety concerns highlight the need for natural, eco-friendly ingredients. In this study, we evaluated the efficacy of solubilized sturgeon oil (SSO), prepared as an oil-in-water nanoemulsion from Siberian sturgeon, as an eco-friendly preventive nasal spray agent against ARIs. Intranasal pre-treatment with SSO effectively inhibited respiratory infections caused by SARS-CoV-2, influenza A virus (IAV), and respiratory syncytial virus (RSV). Additionally, it suppressed viral replication in both nasal and lung tissues. This antiviral effect was linked to reduced pulmonary inflammation, characterized by decreased infiltration of Ly-6C+ monocytes and Ly-6G+ neutrophils, along with lower pro-inflammatory cytokine levels. Histopathological analyses confirmed that nasal SSO administration significantly mitigated lung inflammation progression caused by viral infections. Notably, the protective effects of SSO against SARS-CoV-2, IAV, and RSV persisted for at least six hours following nasal application. These findings highlight SSO as a promising eco-friendly and safe candidate for nasal spray formulations, providing a potential frontline defense against ARIs.

The impact of the COVID-19 pandemic on antibiotic prescription rates in out-of-hours primary care - a register-based study in Denmark

BACKGROUND

Antibiotic prescription rates can be affected by pandemic measures such as lockdowns, social distancing, and remote consultations in general practice. Therefore, such emergency states may negatively affect antimicrobial stewardship, specifically in out-of-hours (OOH) primary care. As contact patterns changed in the COVID-19 pandemic, it would be relevant to explore the impact on antimicrobial stewardship.

AIM

To study the impact of the pandemic on antibiotic prescription rates in OOH primary care, overall and per age group.

METHODS

This cross-sectional register-based study used routine data from OOH primary care in the Central Denmark Region. We included all patient contacts in two equivalent time periods: pre-pandemic and pandemic period. The main outcome measure was defined as the number of antibiotic prescriptions per contact (antibiotic prescription rate).

RESULTS

The overall antibiotic prescription rate decreased during the first year of the pandemic compared to the pre-pandemic period (RR = 0.97, 95%CI: 0.96-0.98). Likewise, the rate decreased for clinic consultations (RR = 0.63, 95%CI: 0.62-0.64). However, an increase was seen for telephone consultations (RR = 1.73, 95%CI: 1.70-1.76). The decline in clinic consultations was largest for consultations involving children aged 0-10 years (RR = 0.53, 95%CI: 0.51-0.56).

CONCLUSION

Antibiotic prescription rates in Danish OOH primary care decreased during the first year of the COVID-19 pandemic, especially for young children. Prescription rates decreased in clinic consultations, whereas the rates increased in telephone consultations. Further research should explore if antibiotic prescription rates have returned to pre-pandemic levels, and if the introduction of video consultations has affected antibiotic prescription patterns in OOH primary care.

Epidemiology of respiratory viruses according to age group, 2023-24 winter season, Kyoto, Japan

The seasonality and epidemiology of viral acute respiratory infections (ARIs) have changed since the coronavirus disease 2019 pandemic. However, molecular-based ARI surveillance has not been conducted in Japan. We developed a regional surveillance program to define the local epidemiology of ARIs. Between December 2023 and March 2024, 2,992 upper respiratory samples collected from patients suspected of having ARIs at five facilities in Kyoto City, Japan, were tested for SARS-CoV-2, influenza virus, and respiratory syncytial virus (RSV) using RT‒PCR. Samples negative for these viruses were randomly selected for testing with the FilmArray Respiratory Panel, and the detection rates of other viruses were estimated. SARS-CoV-2, influenza virus, and RSV were detected in 598 (20.3%), 165 (5.6%), and 40 (1.4%) of the 2,949 samples with valid RT‒PCR results, respectively. The most prevalent viruses in the < 6, 6-17, 18-64, and ≥ 65 year age groups were rhinovirus/enterovirus, RSV, and SARS-CoV-2; influenza virus, seasonal coronavirus, and rhinovirus/enterovirus; SARS-CoV-2, seasonal coronavirus, and influenza virus; and SARS-CoV-2, seasonal coronavirus, and influenza virus, respectively. Significant differences in the detection rates of these viruses were detected between the age groups. This study highlights the importance of age-stratified molecular-based surveillance for a comprehensive understanding of the epidemiology of ARIs.

Cell therapies for viral diseases: a new frontier

Despite advances in medicine and antimicrobial research, viral infections continue to pose a major threat to human health. While major strides have been made in generating vaccines and small molecules to combat emerging pathogens, new modalities of treatment are warranted in diseases where there is a lack of treatment options, or where treatment cannot fully eradicate pathogens, as in HIV infection. Cellular therapies, some of which are FDA approved for treating cancer, take advantage of our developing understanding of the immune system, and harness this knowledge to enhance, or direct, immune responses toward infectious agents. As with cancer, viruses that evade immunity, do so by avoiding immune recognition or by redirecting the cellular responses that would eradicate them. As such, infusing virus specific immune cells has the potential to improve patient outcomes and should be investigated as a potential tool in the arsenal to fight infection. The present manuscript summarizes key findings made using cellular therapies for the treatment of viral infections, focusing on the potential that these strategies might have in controlling disease.

Spectrum of respiratory viruses identified from SARS-CoV-2-negative human respiratory tract specimens in Watansoppeng, Indonesia

Respiratory infections account for millions of hospital admissions worldwide. The aetiology of respiratory infections can be attributed to a diverse range of pathogens including viruses, bacteria and fungi. SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2)-negative specimens from Wattansoppeng city, South Sulawesi, were analysed to study the spectrum of respiratory viruses. Samples were screened for influenza virus, enterovirus, Paramyxoviridae, Nipah virus, Coronaviridae and Pneumoviridae. Of 210 specimens, 19 were positive for respiratory syncytial virus (RSV)-A, RSV-B, human parainfluenza virus type 1 (HPIV-1), HPIV-2, human rhinovirus (HRV)-A, HRV-B, HRV-C, human metapneumovirus (HMPV), influenza A virus (IAV) and coxsackievirus A6 (CV-A6). Influenza virus was of seasonal H3N2 subtype. The HMPVs were of genotypes B1 and A2a, while one RSV-A was of the ON-1 genotype. The viruses mostly affected children with unknown severity.

Supporting vaccine (co)-administration decisions: Development and validation of a tool for assessing the risk of severe outcomes due to lower respiratory tract infections

OBJECTIVE

To develop and validate a score to predict the 90-day risk of hospitalization/death in patients with low respiratory tract infections (LRTIs) with the aim to support clinical decision making on vaccine (co)-administration.

METHODS

We formed a cohort of patients aged 18 years or older being diagnosed with LRTIs in the period between January 1, 2012 and December 31, 2022. Each patient was followed until occurrence of respiratory-related hospitalization/death up to the end of the study period (December 31, 2022). Along with age and sex, forty determinants were adopted to assemble the respiratory tract infection (RTI)-Health Search (HS) core using the development sub-cohort. The prediction accuracy of the score was therefore assessed in the validation sub-cohort.

RESULTS

We identified 252,319 patients being diagnosed with LRTIs (females: 54.7 %; mean age: 60 (SD:18.1)). When the risk of LRTIs-related hospitalizations/deaths was estimated via RTI-HScore, its predicted value was equal to 1.4 % over a 90-day event horizon. The score showed explained variation and discrimination accuracy were equal to 45 % (95 % CI: 44-47 %) and 81 % (95 % CI: 79-84 %), respectively. The calibration slope did not significantly differ from the unit (p = 0.8314).

CONCLUSIONS

The RTI-HScore was featured by good accuracy for prediction of LRTIs-related complications over a 90-day follow-up. Such a tool might therefore support general practitioners to enhance patients' care by facilitating approaches for (co)-administration of vaccines for respiratory infections through a score-based decision support system.

The Impact of Pretransplant Respiratory Virus Detection on Posttransplant Outcomes in Children Undergoing Hematopoietic Cell Transplantation

BACKGROUND

Pretransplant respiratory virus (RV) infections have been associated with negative transplant outcomes in adult hematopoietic cell transplantation (HCT) recipients. In the era of HCT delay because of high-risk RVs, we examined the impact of pretransplant RV detection on transplant outcomes in pediatric HCT recipients.

METHODS

This retrospective cohort study included pediatric myeloablative allogeneic HCT recipients from 2010 to 2019. All patients were screened for RV at least once within 90 days before HCT using reverse transcriptase polymerase chain reaction (PCR), regardless of symptoms. Posttransplant outcomes included days alive and out of hospital and progression to lower respiratory tract infection (LRTI).

RESULTS

Among 310 patients, 134 had an RV detected in the 90 days before HCT. In univariable analysis, transplant factors including younger age, total body irradiation, umbilical cord blood transplantation, lymphocyte count <100/mm3, HCT comorbidity index score ≥3, and viral factors including symptomatic infection, human rhinovirus as a virus type, and symptomatic pretransplant upper respiratory tract infection were associated with fewer days alive and out of hospital. In multivariable analysis, transplant factors remained significant, but not viral factors. There was a higher incidence of progression to posttransplant LRTI with the same pretransplant RV if the last positive PCR before HCT was ≤30 days compared with >30 days (P = .007).

CONCLUSIONS

In the setting of recommending HCT delay for high-risk RVs, symptomatic upper respiratory tract infection, including human rhinovirus infections, may lead to increased duration of hospitalization and early progression to LRTI when transplantation is performed within 30 days of the last positive PCR test.

Severe Bacterial Superinfection of Influenza Pneumonia in Immunocompetent Young Patients: Case Reports

Influenza can lead to or coexist with severe bacterial pneumonia, with the potential to permanently damage lung tissue, refractory to conservative treatment in the post-COVID-19 period. It can lead to serious complications; therefore, annual vaccinations are recommended. This case series with a literature review pertains to two young female patients with an insignificant past medical history, who required emergency lobectomy due to bacterial complications after influenza infection. Urgent lobectomy proves to be a feasible therapeutic option for selected patients with pleural complications.

Prevalence of Co-Infections in Primary Care Patients with Medically Attended Acute Respiratory Infection in the 2022/2023 Season

In the post-pandemic period, an endemic circulation of respiratory viruses has been re-established. Respiratory viruses are co-circulating with SARS-CoV-2. We performed a retrospective analysis of co-infections in primary care patients with medically attended acute respiratory infections (MAARI) who consulted from week 40/2022 to week 39/2023 and were tested for a panel of respiratory viruses. Out of 2099 samples tested, 1260 (60.0%) were positive for one virus. In 340 samples, co-infection was detected: two viruses in 281 (13.4%), three viruses in 51 (2.4%), and four viruses in eight (0.4%) samples. Respiratory viruses co-infected the patients with MAARI at very different rates. The lowest rates of co-infections were confirmed for influenza B (13.8%) and influenza A (22.9%) and the highest for human bocaviruses (84.0%) and human parechoviruses (82.1%). Co-infections were detected in 28.2% of SARS-CoV-2 positive samples. SARS-CoV-2 has never been co-infected with influenza B virus, enterovirus or adenovirus, although the latter was found as a co-infecting virus with all other respiratory viruses tested. The rate of co-infections decreased significantly with increasing age (p-value 0.000), and no difference was found regarding gender (p-value 0.672). It is important to understand the epidemiology of respiratory co-infections for prevention and management decisions in patients with MAARI.

Breaking boundaries in microbiology: customizable nanoparticles transforming microbial detection

The detection and identification of microorganisms are crucial in microbiology laboratories. Traditionally, detecting and identifying microbes require extended periods of incubation, significant manual effort, skilled personnel, and advanced laboratory facilities. Recent progress in nanotechnology has provided novel opportunities for detecting and identifying bacteria, viruses, and microbial metabolites using customized nanoparticles. These improvements are thought to have the ability to surpass the constraints of existing procedures and make a substantial contribution to the development of rapid microbiological diagnosis. This review article examines the customizability of nanoparticles for detecting bacteria, viruses, and microbial metabolites and discusses recent cutting-edge studies demonstrating the use of nanotechnology in biomedical research.

Discovery of GS-7682, a Novel 4'-Cyano-Modified C-Nucleoside Prodrug with Broad Activity against Pneumo- and Picornaviruses and Efficacy in RSV-Infected African Green Monkeys

Acute respiratory viral infections, such as pneumovirus and respiratory picornavirus infections, exacerbate disease in COPD and asthma patients. A research program targeting respiratory syncytial virus (RSV) led to the discovery of GS-7682 (1), a novel phosphoramidate prodrug of a 4'-CN-4-aza-7,9-dideazaadenosine C-nucleoside GS-646089 (2) with broad antiviral activity against RSV (EC50 = 3-46 nM), human metapneumovirus (EC50 = 210 nM), human rhinovirus (EC50 = 54-61 nM), and enterovirus (EC50 = 83-90 nM). Prodrug optimization for cellular potency and lung cell metabolism identified 5'-methyl [(S)-hydroxy(phenoxy)phosphoryl]-l-alaninate in combination with 2',3'-diisobutyrate promoieties as being optimal for high levels of intracellular triphosphate formation in vitro and in vivo. 1 demonstrated significant reductions of viral loads in the lower respiratory tract of RSV-infected African green monkeys when administered once daily via intratracheal nebulized aerosol. Together, these findings support additional evaluation of 1 and its analogues as potential therapeutics for pneumo- and picornaviruses.

Viral infections causing asthma exacerbations in the age of biologics and the COVID-19 pandemic

PURPOSE OF REVIEW

Asthma exacerbations are associated with substantial symptom burden and healthcare costs. Viral infections are the most common identified cause of asthma exacerbations. The epidemiology of viral respiratory infections has undergone a significant evolution during the COVID-19 pandemic. The relationship between viruses and asthmatic hosts has long been recognized but it is still incompletely understood. The use of newly approved asthma biologics has helped us understand this interaction better.

RECENT FINDINGS

We review recent updates on the interaction between asthma and respiratory viruses, and we address how biologics and immunotherapies could affect this relationship by altering the respiratory mucosa cytokine milieu. By exploring the evolving epidemiological landscape of viral infections during the different phases of the COVID-19 pandemic, we emphasize the early post-pandemic stage, where a resurgence of pre-pandemic viruses with atypical seasonality patterns occurred. Finally, we discuss the newly developed RSV and SARS-CoV-2 vaccines and how they reduce respiratory infections.

SUMMARY

Characterizing how respiratory viruses interact with asthmatic hosts will allow us to identify tailored therapies to reduce the burden of asthma exacerbations. New vaccination strategies are likely to shape the future viral asthma exacerbation landscape.

Post-Coronavirus Disease 2019 Pandemic Antimicrobial Resistance

BACKGROUND AND AIM

Antimicrobial resistance (AMR) is a chronic issue of our Westernized society, mainly because of the uncontrolled and improper use of antimicrobials. The coronavirus disease 2019 (COVID-19) pandemic has triggered and expanded AMR diffusion all over the world, and its clinical and therapeutic features have changed. Thus, we aimed to review evidence from the literature on the definition and causative agents of AMR in the frame of the COVID-19 post-pandemic era.

METHODS

We conducted a search on PubMed and Medline for original articles, reviews, meta-analyses, and case series using the following keywords, their acronyms, and their associations: antibiotics, antimicrobial resistance, severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), COVID-19 pandemic, personal protective equipment.

RESULTS

AMR had a significant rise in incidence both in in-hospital and outpatient populations (ranging from 5 up to 50%) worldwide, but with a variegated profile according to the germ and microorganism considered. Not only bacteria but also fungi have developed more frequent and diffuse AMR. These findings are explained by the increased use and misuse of antibiotics and preventive measures during the first waves of the SARS-CoV2 pandemic, especially in hospitalized patients. Subsequently, the reduction in and end of the lockdown and the use of personal protective equipment have allowed for the indiscriminate circulation of resistant microorganisms from low-income countries to the rest of the world with the emergence of new multi- and polyresistant organisms. However, there is not a clear association between COVID-19 and AMR changes in the post-pandemic period.

CONCLUSIONS

AMR in some microorganisms has significantly increased and changed its characteristics during and after the end of the pandemic phase of COVID-19. An integrated supranational monitoring approach to this challenge is warranted in the years to come. In detail, a rational, personalized, and regulated use of antibiotics and antimicrobials is needed.

Sphingosine Prevents Rhinoviral Infections

Rhinoviral infections cause approximately 50% of upper respiratory tract infections and novel treatment options are urgently required. We tested the effects of 10 μM to 20 μM sphingosine on the infection of cultured and freshly isolated human cells with minor and major group rhinovirus in vitro. We also performed in vivo studies on mice that were treated with an intranasal application of 10 μL of either a 10 μM or a 100 μM sphingosine prior and after infection with rhinovirus strains 1 and 2 and determined the infection of nasal epithelial cells in the presence or absence of sphingosine. Finally, we determined and characterized a direct binding of sphingosine to rhinovirus. Our data show that treating freshly isolated human nasal epithelial cells with sphingosine prevents infections with rhinovirus strains 2 (minor group) and 14 (major group). Nasal infection of mice with rhinovirus 1b and 2 is prevented by the intranasal application of sphingosine before or as long as 8 h after infection with rhinovirus. Nasal application of the same doses of sphingosine exerts no adverse effects on epithelial cells as determined by hemalaun and TUNEL stainings. The solvent, octylglucopyranoside, was without any effect in vitro and in vivo. Mechanistically, we demonstrate that the positively charged lipid sphingosine binds to negatively charged molecules in the virus, which seems to prevent the infection of epithelial cells. These findings indicate that exogenous sphingosine prevents infections with rhinoviruses, a finding that could be therapeutically exploited. In addition, we demonstrated that sphingosine has no obvious adverse effects on the nasal mucosa. Sphingosine prevents rhinoviral infections by a biophysical mode of action, suggesting that sphingosine could serve to prevent many viral infections of airways and epithelial cells in general. Future studies need to determine the molecular mechanisms of how sphingosine prevents rhinoviral infections and whether sphingosine also prevents infections with other viruses inducing respiratory tract infections. Furthermore, our studies do not provide detailed pharmacokinetics that are definitely required before the further development of sphingosine.

The specifics of encephalitis after COVID-19

Encephalitis is a group of acute infectious diseases affecting the substance of the brain. They often lead to disability or death, and, therefore, require urgent medical attention. The article discusses the etiology, pathogenesis, and clinical picture of encephalitis, with special attention to the course of this disease after the COVID-19 pandemic. We note the growing number of encephalitis cases, especially of autoimmune variety and those caused by herpes. The possible reason behind this trend is the disruption of operation of the immune system brought by COVID-19, which manifests as a cytokine storm, neuroinflammation, and autoimmune reactions. There are cases of COVID-19-dependent encephalitis described. The pathways taken by SARS-CoV-2 to penetrate into the cells of the central nervous system have not yet been fully studied, although there are hypotheses that this happens both trans-synaptically through mechanoreceptors and chemoreceptors of the respiratory system into the medulla oblongata, and through receptors of the angiotensin converting enzyme 2.