The return of the RSV

Respiratory syncytial virus (RSV) hospitalizations disappeared in 2020. Now, with southern hemisphere 2021 winter behind us, RSV has returned. Despite it is difficult to weigh the impact of pandemic mitigation measures on common respiratory virus circulation, it appears that acute respiratory infections in children are returning to their usual epidemiology.

Molecular Epidemiological Characteristics of Human Rhinovirus Circulating in Shanghai, 2012 - 2020

Background Human Rhinoviruses (HRVs) are a common respiratory virus causing acute exacerbations of asthma, chronic obstructive pulmonary disease (COPD) and other related diseases. The sequence of 5’ untranslated region (UTR) and VP4/VP2 coding region of the genome are usually analyzed to classify HRV as HRV-A, HRV-B and HRV-C. Given the interest for new viral strains, we identified the phylogenetic characteristics and molecular epidemiological analysis of human rhinovirus in Shanghai from 2012 to 2020. Methods 6711 throat swabs and sputum samples from patients with acute respiratory infection (ARI) were collected, then the real-time reverse-transcriptase polymerase chain reaction (RT-PCR) method was used to detect HRV. And the fragment of 5 ' untranslated region (5'UTR) and the VP4/VP2 region were amplified for sequencing and gene typing. Results In total, 480/6711(7.2%) HRV-positive samples were detected from 2012–2020, in which 160 samples were further genotyped to HRV-A (109/160, 68.13%), HRV-B (32/160, 20.00%), HRV-C (19/160, 11.88%). We found 13 samples with unclassified results using 5'UTR. Then, these unclassified sample were genotyped to HRV-A and HRV-C by sequencing the VP4/VP2 region. The high incidence of HRV infection occurs in the fall and it is more prevalent in children than in adults. Conclusion Our study suggests that it is very significant to continuously detect and analyze the genotype distribution and epidemic trend of HRV, which can provide data support for disease prevention and treatment. And the 5' UTR and VP4/VP2 should be combined for HRV genotyping accurately.

Impact of social distancing on the spread of common respiratory viruses during the coronavirus disease outbreak

During the coronavirus disease (COVID-19) pandemic, social distancing was effective in controlling disease spread across South Korea. The impact of national social distancing on the spread of common respiratory virus infections has rarely been investigated. We evaluated the weekly proportion of negative respiratory virus polymerase chain reaction (PCR) test results and weekly positive rates of each respiratory virus during the social distancing period (10th–41st weeks of 2020) and the corresponding period in different years, utilizing the national respiratory virus surveillance dataset reported by the Korean Center for Disease Control and Prevention. The proportions of negative respiratory virus PCR test results increased up to 87.8% and 86.1% during level 3 and level 2 of the social distancing period, respectively. The higher the level of social distancing, the higher the proportion of negative respiratory virus PCR test results. During the social distancing period, the mean weekly positive rates for parainfluenza virus, influenza virus, human coronavirus, and human metapneumovirus were significantly lower than those during the same period in 2015–2019 (0.1% vs. 9.3%, P <0.001; 0.1% vs. 7.2%, P <0.001; 0.4% vs. 2.3%, P <0.001; and 0.2% vs. 5.3%, P <0.001, respectively). The mean positive rate for rhinovirus/enterovirus during level 3 social distancing was lower than that in the same period in 2015–2019 (8.5% vs. 19.0%, P <0.001), but the rate during level 1 social distancing was higher than that in the same period in 2015–2019 (38.3% vs. 19.4%, P <0.001). The national application of social distancing reduced the spread of common respiratory virus infections during the COVID-19 pandemic.

Implications of pre-existing asthma on COVID-19 pathogenesis

The coronavirus disease 2019 (COVID-19) pandemic spreading at an alarming rate has taken a heavy toll on the public healthcare systems and economies worldwide. An abnormal and overactivated inflammatory response is occasionally elicited by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and this hyperinflammation is associated with worse prognosis of COVID-19. Theoretically, one would expect asthma patients to be at a greater risk of SARS-CoV-2 infection considering their increased susceptibility to common respiratory virus-associated exacerbations. Surprisingly, current data do not consistently suggest an increased prevalence of asthma among COVID-19 patients. Considering the high global prevalence of asthma, the characteristics of the disease and/or their conventional therapy might play a role in their potential defense against COVID-19. This may be attributed to the T helper type 2 immune response predominantly seen in asthmatics. Likewise, asthma therapeutics, including corticosteroids and biologics, may in fact benefit the asthmatics by alleviating the development of hyperinflammation. On the other hand, elevated IL-17 levels are characteristically seen in a subset of asthma patients with severe disease as well as in COVID-19 patients. Targeting the IL-17 pathway as a treatment strategy could plausibly alleviate acute respiratory distress syndrome (ARDS) in COVID-19 patients with asthma demonstrating a predominant T helper type 17 response. A clinical trial including a drug targeting this pathway may thus, constitute a logical addition to the global pursuit for effective therapeutics against COVID-19. The complex interplay between the asthma endotypes and COVID-19 is not very well understood and will be discussed in this mini-review.

If Not COVID-19 What Is It? Analysis of COVID-19 versus Common Respiratory Viruses among Symptomatic Health Care Workers in a Tertiary Infectious Disease Referral Hospital in Manila, Philippines

The COVID-19 global pandemic is entering its second year. In this short report we present additional results as a supplement to our previous paper on COVID-19 and common respiratory virus screening for healthcare workers (HCWs) in a tertiary infectious disease referral hospital in Manila, Philippines. We sought to understand what etiologic agents could explain the upper/lower respiratory tract infection-like (URTI/LRTI-like) symptoms exhibited by 88% of the 324 HCWs tested. Among the patients who had URTI/LRTI-like symptoms, only seven (2%) were positive for COVID-19, while 38 (13%) of the symptomatic participants were identified positive for another viral etiologic agent. Rhinovirus was the most common infection, with 21 (9%) of the symptomatic participants positive for rhinovirus. Based on these results, testing symptomatic HCWs for common respiratory illnesses in addition to COVID-19 should be considered during this time of global pandemic.

scRNA-seq reveals ACE2 and TMPRSS2 expression in TROP2+ Liver Progenitor Cells: Implications in COVID-19 associated Liver Dysfunction

SummaryThe recent pandemic of coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 was first reported in China (December 2019) and now prevalent in ∼170 countries across the globe. Entry of SARS-CoV-2 into mammalian cells require the binding of viral Spike (S) proteins to the ACE2 (angiotensin converting enzyme 2) receptor. Once entered the S protein is primed by a specialised serine protease, TMPRSS2 (Transmembrane Serine Protease 2) in the host cell. Importantly, beside respiratory symptoms, consistent with other common respiratory virus infection when patients become viraemic, a significant number of COVID-19 patients also develop liver comorbidities. We explored if specific target cell-type in the mammalian liver, could be implicated in disease pathophysiology other than the general deleterious response to cytokine storms. Here we employed single-cell RNA-seq (scRNA-seq) to survey the human liver and identified potentially implicated liver cell-type for viral ingress. We report the co-expression of ACE2 and TMPRSS2 in a TROP2+ liver progenitor population. Importantly, we fail to detect the expression of ACE2 in hepatocyte or any other liver (immune and stromal) cell types. These results indicated that in COVID-19 associated liver dysfunction and cell death, viral infection of TROP2+ progenitors in liver may significantly impaired liver regeneration and could lead to pathology.Highlights- EPCAM+ Liver progenitors co-express ACE2 and TMPRSS2- ACE2 and TMPRSS2 expression is highest in TROP2high progenitors- ACE2 and TMPRSS2 cells express cholangiocyte biased fate markers- ACE2 and TMPRSS2 positive cells are absent in human fetal liver

Antibiotic Minocycline Prevents Respiratory Syncytial Virus Infection

Treatment drugs, besides their specific activity, often have multiple effects on the body. The undesired effect of the drug may be repurposed as therapeutics, saving significant investigative time and effort. Minocycline has anti-cancer, anti-oxidant, anti-inflammatory, and anti-apoptotic properties. Presently, minocycline is also known to show anti-viral activity against Influenza virus, Japanese encephalitis virus, Simian immunodeficiency virus, Human immunodeficiency virus and West Nile virus. Here, we investigate the effect of minocycline on Respiratory syncytial virus (RSV), a common respiratory virus that causes severe mortality and morbidity in infants, children, and older adult populations. Currently, there is no effective vaccine or treatment for RSV infection; hence, there is a critical need for alternative and effective drug choices. Our study shows that minocycline reduces the RSV-mediated cytopathic effect and prevents RSV infection. This is the first study demonstrating the anti-viral activity of minocycline against RSV.