Globally 113 702 confirmed (4125 new) 4012 deaths (203 new) China 80 924 confirmed (20 new) 3140 deaths (17 new) Outside of China 32 778 confirmed (4105 new) 872 deaths (186 new) 109 countries/territories/ areas (5 new) WHO RISK ASSESSMENT China Very High Regional Level Very High Global Level Very High HIGHLIGHTS • 5 new countries/territories/areas (Brunei Darussalam, Mongolia, Cyprus, Guernsey and Panama) have reported cases of COVID-19 in the past 24 hours. 1 https://www.iatatravelcentre.com/international-travel-document-news/1580226297.htm 2 https://pandemic.internationalsos.com/2019-ncov/ncov-travel-restrictions-flight-operations-and-screening 3 https://www.iata.org/en/pressroom/pr/2020-03-02-01/ 4 https://www.who.int/ith/2019-nCoV_advice_for_international_traffic-rev/en/

Epidemiologic data suggested that there was an obvious predominance of young adult patients with a slight female proneness in severe acute respiratory syndrome (SARS). The angiotensin-converting enzyme 2 (ACE2) was very recently identified as a functional receptor for SARS virus and is therefore a prime target for pathogenesis and pharmacological intervention. Rats of both genders at three distinct ages (young-adult, 3 months; middle-aged, 12 months; old, 24 months) were evaluated to determine the characteristic of ACE2 expression in lung and the effect of aging and gender on its expression. ACE2 was predominantly expressed in alveolar epithelium, bronchiolar epithelium, endothelium and smooth muscle cells of pulmonary vessels with similar content, whereas no obvious signal was detected in the bronchiolar smooth muscle cells. ACE2 expression is dramatically reduced with aging in both genders: young-adult vs. old P < 0.001 (by 78% in male and 67% in female, respectively) and middle-aged vs. old P < 0.001 (by 71% in male rats and 59% in female rats, respectively). The decrease of ACE2 content was relatively slight between young-adult and middle-aged groups (by 25% in male and 18% in female, respectively). Although there was no gender-related difference of ACE2 in young-adult and middle-aged groups, a significantly higher ACE2 content was detected in old female rats than male. In conclusion, the more elevated ACE2 in young adults as compared to aged groups may contribute to the predominance in SARS attacks in this age group.

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This preliminary study showed that intravenous infusion of autologous EPCs seemed to be feasible and safe, and might have beneficial effects on exercise capacity and pulmonary hemodynamics in patients with IPAH. (Safety and Efficacy Study of Transplantation of EPCs to Treat Idiopathic Pulmonary Arterial Hypertension; http://www.clinicaltrials.gov/ct/show/NCT00257413?order=1; NCT00257413).

Our observations indicated that EPC numbers and functional capacity were impaired in patients with IPAH, which might not only give potential insight into the pathophysiological mechanisms but also might be useful for identifying suitable therapeutic targets in these patients.

Background The clinical characteristics and outcome of COVID-19 in children are different from those in adults. We aimed to describe the characteristics of infants under 1 year of age (excluding newborns) with COVID-19. Methods We retrospectively retrieved data of 36 infants with SARS-CoV-2 infection in Wuhan Children's Hospital from January 26 to March 22, 2020. Clinical features, chest imaging findings, laboratory tests results, treatments and clinical outcomes were analyzed. Results The mean age of the infected infants was 6.43 months, with a range of 2-12 months. 61.11% of the patients were males and 38.89% females. 86.11% of the infants were infected due to family clustering. Cough (77.78%) and fever (47.22%) were the most common clinical manifestations. Chest CT scan revealed 61.11% bilateral pneumonia and 36.11% unilateral pneumonia. 47.22% of the infants developed complications. Increased leucocytes, neutrophils, lymphocytes, and thrombocytes were observed in 11.

Previous studies showed that high concentration of particulate matter (PM) 2.5 and PM10 carried a large number of bacterial and archaeal species, including pathogens and opportunistic pathogens. In this study, pharyngeal swabs from 83 subjects working in an open air farmer’s market were sampled before and after exposure to smog with PM2.5 and PM10 levels up to 200 and 300 μg/m3, respectively. Their microbiota were investigated using high-throughput sequencing targeting the V3–V4 regions of the 16S rRNA gene. The genus level phylotypes was increased from 649 to 767 in the post-smog pharyngeal microbiota, of which 142 were new and detected only in the post-smog microbiota. The 142 new genera were traced to sources such as soil, marine, feces, sewage sludge, freshwater, hot springs, and saline lakes. The abundance of the genera Streptococcus, Haemophilus, Moraxella, and Staphylococcus increased in the post-smog pharyngeal microbiota. All six alpha diversity indices and principal component analysis showed that the taxonomic composition of the post-smog pharyngeal microbiota was significantly different to that of the pre-smog pharyngeal microbiota. Redundancy analysis showed that the influences of PM2.5/PM10 exposure and smoking on the taxonomic composition of the pharyngeal microbiota were statistically significant (p < 0.001). Two days of exposure to high concentrations of PM2.5/PM10 changed the pharyngeal microbiota profiles, which may lead to an increase in respiratory diseases. Wearing masks could reduce the effect of high-level PM2.5/PM10 exposure on the pharyngeal microbiota.

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