Clinical features of severe acute respiratory syndrome coronavirus-2 Omicron variant infection in mother-infant dyads during lactation

Objective To summarize the clinical features, viral load changes, and outcomes of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Omicron variant infection in mother-infant dyads during lactation period. Methods A total of 24 pairs of lactating mothers and infants under one year old who were infected with SARS-CoV-2 and hospitalized in Lingang Branch of Shanghai Sixth People's Hospital from April 8 to May 30, 2022, were selected as the lactation group in this retrospective study. Another 24 non-lactating mothers, with children of one to three years old, who matched with those mothers in the lactation group in clinical classification and admission date were selected as the control group. Vaccination status, clinical symptoms, daily cycle threshold (Ct) of open reading frame 1ab (ORF1ab) gene and nucleocapsid protein (N) gene, and the duration of positive nucleic acid test were compared between the groups and were analyzed using two independent samples t test, one-way analysis of variance, LSD test, and Chi-square test. Results Among the 24 infants in the lactation group with an age of (6.5±2.1) months, 23 cases were mild type, one was common, and none had been vaccinated against SARS-CoV-2. The maternal age of the lactation and the control group did not differ statistically [(28.7±6.4) vs (28.2±5.2) years, t=0.30, P=0.768]. Mothers with mild type accounted for 88% (21/24) and those with common for 12% (3/24) in both groups of mothers. Three mothers received one dose of vaccine and two received two in the lactation group, while three received one dose and three received two in the control group [21%(5/24) vs 25%(6/24), χ2=0.12, P=0.731]. The most common symptoms of lactating infants were fever (100%, 24/24), followed by diarrhea (58%, 14/24), cough (50%, 12/24), and wheeze (29%, 7/24), those of the lactating mothers were fever (75%, 18/24), cough (75%, 18/24), and sore throat (63%, 15/24), while those of non-lactating mothers were cough (88%, 21/ 24), sore throat (71%, 17/24), and fever (58%, 14/24). The duration of positive nucleic acid test was the shortest in the lactating infants [(9.2±2.1) d (5-14 d)], followed by mothers in the control group [(11.2± 2.4) d (6-16 d)] and mothers in the lactation group [(14.0±4.2) d (8-26 d)] (LSD test, all P<0.05). Each day from day 2 to 9 after diagnosis, Ct values of nucleic acid of infants in the lactation group were all higher than those of mothers in both the lactation and control groups (LSD test, all P<0.05). On day 10, Ct value of nucleic acid infants was higher than that in mothers in the lactation group (ORF1ab gene: 37.91±4.34 vs 32.79±5.47;N gene: 37.95±4.58 vs 32.66±5.77), which was lower than those in mothers in the control group (ORF1ab gene: 32.79±5.47 vs 35.90±4.17;N gene: 32.66±5.77 vs 36.08±4.16) (LSD test, all P< 0.05). On day 11, the nucleic acid Ct values of mothers in the lactation group were all lower than those in the control group (ORF1ab gene: 35.03±3.74 vs 37.84±3.26, t=－2.78, P=0.008;N gene: 35.30±3.75 vs 38.11±2.90, t=－2.90, P=0.006). On day 12, Ct value of ORF1ab gene and N gene in mothers in the lactation group were similar to those in mothers in the control group (both P>0.05). Conclusions The SARS-CoV-2 vaccination rate of mothers and infants were low during lactation. Lactating infants infected with SARS-CoV-2 Omicron variant have low virus load and may have a quick recovery, while for the lactating mothers, the virus load is high and the recovery is slow. © 2022 Chinese Medical Journals Publishing House Co.Ltd. All rights reserved.

A prospective cohort study of the presence of SARS-CoV-2 in clinical samples from multiple bodily sites: implications for transmission routes of COVID-19

Objective: The coronavirus disease 2019 (COVID-19) epidemic resulting from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has still spread globally. The occurrence of the Delta variant, which is more infectious and spreads faster than earlier forms of the virus that causes COVID-19, makes infection prevention more challenging. Therefore, this study aimed to gain a comprehensive insight into the transmission routes of SARS-CoV-2 for curbing the propagation of SARS-CoV-2 in human populations. Methods: We studied a prospective cohort of 576 patients admitted consecutively to the First Affiliated Hospital of Guangzhou Medical University from January 21 to June 8, 2020. These patients were chosen based on their similar clinical phenotypes or imaging findings. There were 21 (3.6%) laboratory-confirmed COVID-19 patients (16 severe and 5 mild cases) and 555 non-COVID-19 patients. The antibody response and routes and duration of viral shedding were systematically evaluated in serial clinical specimens. Moreover, SARS-CoV-2 RNA was also detected in a mouth rinse, urine, and tear samples. This study was approved by the Medical Ethical Committee of The First Affiliated Hospital of Guangzhou Medical University (approval No. 2020-77). Results: SARS-CoV-2 mainly existed in sputum, nasal and throat swabs, and feces samples. Virus latency was longer in sputum and feces samples than in nasopharyngeal samples. IgG antibody response in respiratory samples was related to disease severity. Although droplets and aerosols are the major transmission routes for COVID-19, covert routes of transmission from asymptomatic patients, contaminated surfaces, and wastewater are also of interest. Conclusion: Our findings provide a solid foundation for developing prophylactic measures against SARS-CoV-2.

[A pathological report of three COVID-19 cases by minimal invasive autopsies].

Objective: To investigate the pathological characteristics and the clinical significance of novel coronavirus (2019-nCoV)-infected pneumonia (termed by WHO as coronavirus disease 2019, COVID-19). Methods: Minimally invasive autopsies from lung, heart, kidney, spleen, bone marrow, liver, pancreas, stomach, intestine, thyroid and skin were performed on three patients died of novel coronavirus pneumonia in Chongqing, China. Hematoxylin and eosin staining (HE), transmission electron microcopy, and histochemical staining were performed to investigate the pathological changes of indicated organs or tissues. Immunohistochemical staining was conducted to evaluate the infiltration of immune cells as well as the expression of 2019-nCoV proteins. Real time PCR was carried out to detect the RNA of 2019-nCoV. Results: Various damages were observed in the alveolar structure, with minor serous exudation and fibrin exudation. Hyaline membrane formation was observed in some alveoli. The infiltrated immune cells in alveoli were majorly macrophages and monocytes. Moderate multinucleated giant cells, minimal lymphocytes, eosinophils and neutrophils were also observed. Most of infiltrated lymphocytes were CD4-positive T cells. Significant proliferation of type Ⅱ alveolar epithelia and focal desquamation of alveolar epithelia were also indicated. The blood vessels of alveolar septum were congested, edematous and widened, with modest infiltration of monocytes and lymphocytes. Hyaline thrombi were found in a minority of microvessels. Focal hemorrhage in lung tissue, organization of exudates in some alveolar cavities, and pulmonary interstitial fibrosis were observed. Part of the bronchial epithelia were exfoliated. Coronavirus particles in bronchial mucosal epithelia and type Ⅱ alveolar epithelia were observed under electron microscope. Immunohistochemical staining showed that part of the alveolar epithelia and macrophages were positive for 2019-nCoV antigen. Real time PCR analyses identified positive signals for 2019-nCoV nucleic acid. Decreased numbers of lymphocyte, cell degeneration and necrosis were observed in spleen. Furthermore, degeneration and necrosis of parenchymal cells, formation of hyaline thrombus in small vessels, and pathological changes of chronic diseases were observed in other organs and tissues, while no evidence of coronavirus infection was observed in these organs. Conclusions: The lungs from novel coronavirus pneumonia patients manifest significant pathological lesions, including the alveolar exudative inflammation and interstitial inflammation, alveolar epithelium proliferation and hyaline membrane formation. While the 2019-nCoV is mainly distributed in lung, the infection also involves in the damages of heart, vessels, liver, kidney and other organs. Further studies are warranted to investigate the mechanism underlying pathological changes of this disease.