Clinical follow-up study of SARS-CoV-2 Omicron infection / 上海预防医学

ObjectiveTo observe the clinical course and explore the risk factors for SARS-CoV-2 RNA negative conversion duration （NCD） in asymptomatic and mild-symptomatic patients infected with the SARS-CoV-2 Omicron variant. MethodsClinical data were collected from 244 confirmed cases of corona virus disease （COVID-19） with Omicron variant infection admitted to a temporal makeshift hospital in Shanghai from April 9， 2022 to May 20， 2022. Demographic and clinical data were analyzed， with a primary focus on the time of COVID-19 nucleic acid conversion. Univariate and multivariate Cox regression analysis were used to determine identify risk factors associated with NCD. ResultsThe median duration of negative RNA conversion was 9 days （ranged 7‒12 days）. The percentage of patients with positive nucleic acid results on the 5th， 7th， 10th， and 14th days after confirmed infection was 68.4%， 47.1%， 20.1%， and 5.7%， respectively. Kaplan-Meier curves indicated a median nucleic acid conversion time of 12 days （ranged 10‒14 days） for patients with hypertension， 9 days （ranged 7‒11 days） in patients without hypertension， and 11 days （ranged 9‒13 days） for patients aged ≥60 years， and 9 days （ranged 7‒11 days） for patients aged <60 years. Multivariate Cox regression analysis showed that only hypertension was an independent risk factor of NCD （RR=1.60； 95% CI： 1.03‒2.49， P=0.036）. ConclusionIn asymptomatic or mildly symptomatic patients infected with the Omicron variant， 20.1% patients continue to exhibit positive viral nucleic acid on the 10th days of infection. The independent risk factor associated with the conversion of SARS-CoV-2 nucleic acid to negative is hypertension.

Epidemiological characterization of a cluster of COVID-19 caused by SARS-CoV-2 Omicron variant at a construction site in Qingpu District， Shanghai / 上海预防医学

ObjectiveTo determine the epidemiological characteristics of a cluster of SARS-CoV-2 Omicron variant at a construction site and provide evidence for further COVID-19 prevention and control. MethodsDemographic data of all COVID-19 cases at a construction site in Qingpu District， Shanghai， and basic information of the construction site were retrospectively collected through filed investigation. Descriptive epidemiology was used for the analysis. Basic reproduction number （R0） and time-dependent reproduction number （Rt） were calculated using R program. ResultsDuring April 12 and May 8， 2022， a total of 314 cases were reported at the construction site， with an attack rate of 60.62%. The attack rate significantly differed between workers and managers （χ2=10.868， P<0.001）， whereas did not differ statistically by gender （χ2=0.358， P=0.550） or by vaccination status （χ2=2.861， P=0.091）. The age of all cases ranged from 5 months of age to 68 years， with a media age of 49.0 years （interquartile range： 39.8， 54.0）. In all cases， male was predominant （83.44%）. Moreover， the epidemic was mainly concentrated in the workers’ dormitory area， with infected cases identified in all buildings of each dormitory area. The attack rate ranged between 33.33% and 87.50% across the buildings. Symptoms and signs were observed among 43.0% of all cases， of which major clinical manifestations included cough （33.33%）， fever （30.37%） and headache （17.04%）. Clinical manifestations did not differ by gender （χ2=1.275， P=0.259） or by vaccination status （χ2=0.186， P=0.666）. Additionally， R0 was estimated to be 6.08 （95% confidence interval： 4.49‒8.02）. The Rt showed a decline in the beginning， followed by an increase and a re-decline. ConclusionThe cluster epidemic of COVID-19 caused by Omicron variant at the construction site is highly contagious， spreads rapidly and quietly， causes mild symptoms， which finally resulted in a large number of infected cases. It warrants rapid and strict containment when an epidemic occurs at construction sites.

Spatiotemporal characteristics and prevention and control measures of SARS-CoV-2 Omicron pandemic in Shanghai / 上海预防医学

ObjectiveTo analyze the spatiotemporal characteristics and prevention and control measures of the pandemic caused by the SARS-CoV-2 Omicron variant in Shanghai in 2022， aiming to optimize future prevention and control strategies. MethodsDescriptive statistical method was used to analyze data on daily infections released by the Shanghai Municipal Health Commission from March 1 to June 30， 2022. ResultsAs of 30 June， a total of 627 110 infections and 588 deaths had been reported in Shanghai. Most of the cases were in Pudong New Area （35.47%）， Minhang District （10.18%） and Huangpu District （9.27%）. The cumulative infection rate was 8.78% in Huangpu District， which was the highest among all the districts. With the progress of the pandemic， the prevention and control measures were strengthened from a “precise prevention and control” strategy to “block and grid” screening， and then upgraded to city-wide lockdown. All daily new infections were identified from the quarantined population on April 29， 2022， reaching the goal of “clearance of community transmission”. ConclusionThe cumulative infections in Shanghai exceeded any previous epidemics in mainland China. Given the enhanced transmissibility and vaccine-induced immune escape of the Omicron variant， timely and strong public health measures are needed to suppress the pandemic under the general policy of "Dynamic zero-COVID".

Characteristics of digestive system symptoms and abdominal computed tomography imaging of patients infected with severe acute respiratory syndrome coronavirus 2 Omicron variant / 中华消化杂志

Objective:To investigate the characteristics of digestive system symptoms and its relation with the time of nucleic acid continuous positive in population infected with severe acute respiratory syndrome coronavirus 2 Omicron variant, and to analyze the abdominal computed tomography (CT) features of patients infected with Omicron variant.Methods:From April 11 to May 23, 2022, a questionnaire survey was conducted in patients infected with Omicron variant admitted to the Shanghai National Convention and Exhibition Center Fangcang Hospital. The questionnaire included basic information, the start time of nucleic acid positive, respiratory symptoms, digestive system syptoms and outcomes, etc.Combined with the clinical data, the relation between digestive tract symptoms and the time of nucleic acid continuous positive were analyzed. Thoracic and abdominal CT were performed for patients with continuous positive nucleic acid results ≥10 d, and the relationship between the abdominal CT imaging characteristics and the time of nucleic acid continuous positive was analyzed. Independent sample t-test and multivariate logistic regression were used for statistical analysis. Results:A total of 4 360 valid questionnaires were collected, including 2 475 males and 1 885 females, with a hospital stay of (6.8±4.9) d. Among the 4 360 patients, 1 979 patients (45.4%) had gastrointestinal symptoms such as loss of appetite, abdominal discomfort or pain, constipation and diarrhea. The time of nucleic acid continuous positive in patients with gastrointestinal symptoms was (7.4±5.5) d, which was longer than that of patients without gastrointestinal symptoms (6.5±3.6) d, and the difference was statistically significant ( t=3.78, P<0.001). During the isolation period in the Fangcang Hospital, the time of nucleic acid continuous positive in patients with complete remission of digestive tract symptoms was shorter than that of patients with no remission of digestive tract symptoms ((7.3±5.2) d vs. (8.5±5.7) d), and the difference was statistically significant ( t=2.25, P=0.025). The results of multivariate logistic regression analysis showed that the combination of gastrointestinal symptoms was an independent risk factor for continuous positive nucleic acid result ≥10 d ( OR=1.316, 95% confidence interval 1.294 to 2.205, P=0.046). Among the 299 patients with continuous positive nucleic acid results≥10 d, 187 cases (62.5%) had gastrointestinal symptoms, and 146 cases (48.8%) had abdominal CT findings of thickening of the gastroduodenal wall, thickening of the small intestinal wall, indistinct mesenteric vessels of the small intestine, and dilatation and pneumatosis of the colon. In patients with continuous positive nucleic acid results ≥10 d, abdominal CT indicated that patients with gastrointestinal imaging changes had a longer time of nucleic acid continuous positive than those without gastrointestinal imaging changes ((16.0±2.8) d vs. (13.0±2.1) d), and the difference was statistically significant ( t=2.62, P=0.009). Conclusions:Digestive system symptoms are common in patients infected with Omicron variant. The time of nucleic acid continuous positive in patients with gastrointestinal symptoms is longer than those without gastrointestinal symptoms. Some patients may have gastrointestinal lesions on abdominal CT.

Whole-genome characterization and traceability analysis of the first COVID-19 outbreak caused by Omicron variant in Henan Province / 中华微生物学和免疫学杂志

Objective:To analyze the whole genome of Omicron variants causing the first local Omicron outbreak in Henan Province and to investigate the mutations in the SARS-CoV-2 genome for source tracing.Methods:Respiratory tract samples from COVID-19 cases in the Omicron outbreak in Henan Province from January 7 to 29, 2022 were subjected to whole-genome sequencing and sequence alignment analysis. Whole-genome identity, variations and evolution of the Omicron variants were analyzed.Results:Through high-throughput sequencing, the whole-genome sequences of SARS-CoV-2 were obtained from 120 cases, which accounted for 25.64% (120/468) of all COVID-19 cases in Anyang during the same period. Compared with the genome of Wuhan reference strain (NC_045512.2), there were 57-59 nucleotide mutation sites in the 120 whole genome sequences, and one or two nucleotide mutation sites were added to the shared 57 nucleotide sites. All of the 120 strains were VOC/Omicron (BA.1.1) variants and shared high homology. The whole-genome sequence obtained from the first case A contained 57 nucleotide mutation sites, while apart from the 57 identical nucleotide mutation sites, one specific mutation site (C1594T) was found in the whole-genome sequence obtained from the first case B, suggesting that the two cases were in the same transmission chain. After comparing with the database of domestic and imported cases by the Chinese Center for Disease Control and Prevention and the Henan Provincial Center for Disease Control and Prevention, it was found that the current outbreak was linked with the same transmission chain as the existing local epidemics in other provinces. Moreover, epidemiological investigation showed that on January 2, case A had come into contact with her cousin and his family who returned from an affected area outside the province.Conclusions:Based on the gene sequencing results and epidemiological investigation, the COVID-19 outbreak in Anyang city, Henan Province was a local epidemic and the source of it was a college student who returned to Anyang city from other province on December 28, 2021. These infections were linked to the same transmission chain as the existing local infection in other provinces.

Research progress in site mutations of SARS-CoV-2 Omicron variants / 中华微生物学和免疫学杂志

SARS-CoV-2 Omicron variant (B.1.1.529) was first discovered in South Africa in November 2021 and has since become a mainstream strain worldwide. Omicron variant was defined as the fifth "variant of concern (VOC)" by World Health Organization on November 26, 2021. This paper illustrates the mutation trends of Omicron variants in terms of SARS-CoV-2 genome and protein structure as well as nucleic acid site mutations and amino acid site mutations, describes the features of Omicron mutation sites in terms of lineage comparison among the VOCs and Omicron sublineages, and further highlights the influences of Omicron site mutations from the aspects of immune escape, virulence and transmission ability. Moreover, this paper also reviews the development of direct antiviral agents, antibodies and vaccines, aiming to provide reference for further investigation.

Quick guideline for diagnosis and treatment of novel coronavirus Omicron variant infection / 中华临床感染病杂志

Novel coronavirus Omicron variant infection can cause severe illness and even death in certain populations. Omicron variant infection may lead to systemic inflammatory response, coagulation disorder, multi-organ dysfunction and other pathophysiological changes, which are different from other Novel coronavirus variants to a certain extent, so therapeutic strategies should not be the same. The National Medical Center for Major Public Health Events invited experts in fields of infectious diseases, respiratory medicine, intensive care, pediatrics and fever clinic to develop this quick guideline based on the current best evidence and extensive clinical practices. This quick guideline aims to standardize the diagnosis and treatment of novel coronavirus Omicron infection, and to improve the disease management abilities of clinicians.

Clinical characteristics of family clustering pediatric and adult cases with severe acute respiratory syndrome coronavirus 2 Omicron variant infection / 中华传染病杂志

Objective:To investigate the clinical characteristics of family clustering pediatric and adult cases with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection in Shanghai City.Methods:A field investigation among the pediatric cases with Omicron variant infection and their household contacts from April 4 to April 30, 2022 in Children′s Hospital of Fudan University was conducted. The informations on case finding, clinical manifestations and SARS-CoV-2 vaccination status were collected. The epidemiological and clinical characteristics were compared between pediatric cases and adult cases. The independent sample t test or chi-square test was used for statistical analysis, and the relative risk ( RR) and 95% confidence interval (95% CI) were used to evaluate the protective effect of vaccination on the infection of Omicron variant. Results:There were 1 274 family members in 297 families including 370 children and 904 adults of whom 1 110(87.13%) were infected with Omicron variant, with 989(89.10%) symptomatic and 121(10.90%) asymptomatic. There were 355 children infected with Omicron variant, of whom 337(94.93%) were symptomatic, and the main manifestations were fever (96.74%(326/337)) and cough (40.36%(136/337)). Only one pediatric case with Rett syndrome developed critically severe pneumonia. A total of 194 pediatric cases had imaging examination, 64(32.99%) showed pulmonary inflammatory lesions. There were 755 adult cases infected with Omicron variant, of whom 652(86.26%) reported symptoms, and the main manifestations were fever (73.16%(477/652)) and cough (49.85%(325/652)). Among symptomatic cases, fever was more common in pediatric cases than in adult cases, while cough was more common in adult cases than in pediatric cases, and the differences were both statistically significant ( χ2=80.87 and 8.04, respectively, both P<0.01). The fever spike was higher in pediatric cases than in adult cases ((39.3±0.7) ℃ vs (38.6±0.6) ℃), and the difference was statistically significant ( t=9.85, P<0.001). The interval from the onset of symptoms to cycle threshold (Ct) value of the nucleic acid of Omicron variant≥35 was longer in pediatric cases than in adult cases ((13.0±3.1) d vs (10.9±3.6) d), and the difference had statistically significance ( t=2.97, P=0.004). Among 160 children aged 3 to 18 years, 54 (33.75%) received two-dose vaccination. Among the 904 adults, 388 (42.92%) received two-dose vaccination and 293 (32.41%) received a booster dose. In the adult cases, the risk of symptomatic infection was reduced by only 8% ( RR=0.92, 95% CI 0.86 to 0.98, P=0.014) following two-dose vaccination, and the risks of fever and cough following booster vaccination were reduced by 42%( RR=0.58, 95% CI 0.49 to 0.67, P=0.001) and 50% ( RR=0.50, 95% CI 0.34 to 0.78, P=0.001), respectively. Conclusions:Secondary attack rate and symptomatic rate of household infection are high in the context of the Omicron variant outbreak in Shanghai. Symptomatic infection is common in children and adults in household setting. Fever is the most common symptom and fever duration is short. Booster vaccination may provide certain protection against common symptoms caused by Omicron variant infection.

Diagnosis, treatment and prevention of severe acute respiratory syndrome coronavirus 2 infection in children: experts′ consensus statement (Fifth Edition)updated for the Omicron variant / 中华实用儿科临床杂志

China has classified the Corona Virus Disease 2019(COVID-19) as a statutory category B infectious disease and managed it according to Category B since January 8, 2023.In view that Omicron variant is currently the main epidemic strain in China, in order to guide the treatment of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) infection in children with the times, refer to the Diagnosis and Treatment Protocol for Novel Coronavirus Infection (Trial 10 th Edition), Expert Consensus on Diagnosis, Treatment and Prevention of Novel Coronavirus Infection in Children (Fourth Edition) and the Diagnosis and Treatment Strategy for Pediatric Related Viral Infections.The Expert Consensus on the Diagnosis, Treatment and Prevention of Novel Coronavirus Infection in Children (Fifth Edition) has been formulated and updated accordingly on related etiology, epidemiology, pathogenic mechanism, clinical manifestations, auxiliary examination, diagnosis and treatment, and added key points for the treatment of COVID-19 related encephalopathy, fulminating myocarditis and other serious complications for clinical reference.

Epidemiological investigation of a school COVID-19 outbreak in Shanghai / 上海预防医学

ObjectiveTo describe a COVID-19 outbreak due to SARS-CoV-2 Omicron variant in a school and provide suggestions for COVID-19 prevention and control. MethodsData on the COVID-19 outbreak in a school in Putuo District of Shanghai were collected from November 14 to December 20， 2022. Epidemiological characteristics， incidence rate of secondary cases and response measures were described and analyzed. ResultsA total of 27 COVID-19 cases were identified infected with SARS-CoV-2 Omicron BA.5.2 variant， including 14 students （51.9%） and 13 family members / teachers living with those students （48.1%）. The first case occurred on November 14， with peak incidence during November 16-18. The median generation interval of the second generation cases was 2 （2，3） days. The index case （case 1， a student） had a clear contact history outside the school， which was found through routine examination in key populations in the school. Immediate management was conducted after the notification. All the second generation cases were exposed students in the same class with case 1， which were identified during the quarantine， whereas the third generation cases were their family members/teachers living with the second generation cases. The incidence rate within the class and school were 36.8% and 3.0%， respectively. No further social transmission was found outside the school. ConclusionEarly detection， multi-sectoral collaboration， prompt control and quarantine measures are effective in containing SARS-CoV-2 transmission. Health promotion， surveillance， ventilation and prophylactic disinfection should be reinforced in schools， office buildings and other gathering places.

Influencing factors of negative conversion time of nucleic acid detection in 228 patients infected with Omicron variant of SARS-CoV-2 in Shanghai / 中国热带医学

@#Abstract: Objective To analyze and compare the effects of different clinical characteristics on the negative conversion time of nucleic acid detection after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection, and to provide a scientific basis for the isolation and treatment of coronavirus disease 2019 (COVID-19). Methods　The epidemiological and clinical data of 228 mild SARS-CoV-2 Omicron variant infected patients diagnosed in Shanghai were retrospectively collected from April 27, 2022 to June 8, 2022 in Wujiaochang designated Hospital, Yangpu District, Shanghai. The negative conversion time of nucleic acid detection was used as the outcome variable, and the patients were divided into A (≤18 days) and B (>18 days). Univariate and multivariate logistic regression analysis were used to analyze the influencing factors of the negative conversion time of nucleic acid detection. Results　The mean nucleic acid conversion time of 228 patients was (18.7±12.1) d, with the median time of 18 (2-46) d. Among them, 120 patients in group A had an average nucleic acid conversion time of (13.2±2.0) d, and 108 cases in group B had an average nucleic acid conversion time of (20.8±1.3) d. Univariate analysis showed that there were no statistically significant differences in the effects of hypertension, coronary heart disease, diabetes, hypokalemia, malignant tumors, neuropsychiatric diseases, chronic digestive diseases on the negative nucleic acid conversion time (P>0.05); however, there were significant differences in the effects of combined cerebrovascular disease, leukopenia, chronic respiratory system diseases and vaccination on the negative nucleic acid conversion time (P<0.05). Further multivariate logistic regression analysis revealed that the combination of chronic respiratory diseases and non-vaccination were significant risk factors for prolongation of negative nucleic acid conversion time (P<0.05). Conclusions The results of this study show that gender, age and whether hypertension, coronary heart disease, diabetes mellitus, hypokalemia, malignant tumor, neuropsychiatric disease and chronic digestive disease have no significant effect on the nucleic acid conversion time, whereas chronic respiratory disease and no vaccination are significantly correlated with the prolongation of nucleic acid conversion time in SARS-CoV-2 Omicron-infected patients.

The relationship between SARS-CoV-2 vaccination and COVID-19 in children / 中国热带医学

@#Abstract: Objective　To analyze the vaccination status of SARS-CoV-2 in children, and explore the relationship between SARS-CoV-2 vaccination and COVID-19 in children. Methods　A retrospective study was conducted to analyze the clinical data of 335 cases of SARS-CoV-2 Omicron variant infection from February 15, 2022 to March 18, 2022 in Shenzhen Third People's Hospital. Results　Among 335 children with SARS-CoV-2 infection, 174(51.9%) cases were vaccinated with the SARS-CoV-2 vaccine; 33(31.4%) cases were vaccinated in the 3-<6 years old group; 141(61.3%) cases were vaccinated in the 6-<14 years old group. There was a statistically significant difference in the proportion of SARS-CoV-2 vaccination between the 6-<14 years old group and the 3-<6 years old group (χ2=26.1, P<0.05). In the study cohort, 3-<6 years old group and 6-<14 years old group, there was no significant difference in the incidence of COVID-19 in the vaccinated group compared with the unvaccinated group (P>0.05). In the study cohort, the proportion of confirmed cases of 1 dose of SARS-CoV-2 vaccine and 2 doses or more of SARS-CoV-2 vaccine was 89.5% (68 cases) and 77.6% (76 cases), respectively; in the 6~<14 years old group, the proportion of confirmed cases of 1 dose of SARS-CoV-2 vaccine and 2 doses or more of SARS-CoV-2 vaccine was 90.0% (54 cases) and 76.5% (62 cases), respectively; the differences were statistically significant (χ2=4.264, P<0.05; χ2=4.279，P<0.05). The IgG levels of 18.28 (6.61, 55.2) AU/mL and 58.3 (25.85, 131.41) AU/mL in the study cohort who were vaccinated for 1 dose, 2 doses and more, respectively; the IgG levels of 20.13 (8.33, 44.33) AU/mL and 56.57 (25.85, 150.07) AU/mL in the 6~<14 years old group who were vaccinated for 1 dose, 2 doses and more, respectively; and the differences were statistically significant (Z=-4.37, P<0.05; Z=-3.96, P<0.05). Conclusions　Children who received 2 doses of SARS-CoV-2 vaccine have a lower incidence of COVID-19 and higher levels of SARS-CoV-2 antibodies compared with who received 1 dose . It is recommended that children are advised to be vaccinated against the COVID-19.

Epidemiological characteristics of infected patients aged 60 years and older during the outbreak of SARS-CoV-2 Omicron variant in Sanya, Hainan in 2022 / 中国热带医学

@# or older during the outbreak epidemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant in Sanya City, Hainan Province, August-September 2022, and to provide scientific and effective basis for formulating strategies for the prevention and treatment of COVID-19 in the elderly in the future. Methods　The data of 1 785 COVID-19 cases aged ≥60 years reported from August 1 to September 8, 2022 in Sanya City, and 537 local COVID-19 inpatients aged ≥60 years treated in Sanya Central Hospital were collected and analyzed using WPS Office 2018 software for data cleaning, database assistance, and drawing, and SPSS 22.0 software was used to statistically describe and analyze the counting data. Results　A total of 1 785 local COVID-19 cases aged ≥60 years were reported in China's Disease Prevention and Control Information System, including 1 509 confirmed cases (84.54%) and 276 asymptomatic cases (15.46%). Of the confirmed cases, 1 448 were mild cases (95.96%), 40 were common cases (2.65%), 10 were severe cases (0.66%), and 11 were critical cases (0.73%), and no deaths were reported. The ratio of male to female was 0.88∶1. The youngest was 60 years old, the oldest age was 107 years old, with a median age of 67 years old. Most of them (1 559 cases, 87.34%) were non-social employed personnel. Among them, 952 (53.33%) were from Tianya District and 733 (41.06%) from Jiyang District. Among the 537 COVID-19 elderly infected patients hospitalized in Sanya Central Hospital, infected patients with underlying diseases accounted for 287 (53.45%) cases of hypertension, diabetes and other types of basic diseases (chronic kidney disease, hyperlipidemia, chronic gastritis, gastric ulcer, etc.), and there were serious infections. Conclusions　Most of the elderly infected with Omicron variants were mild cases with few symptoms, but the elderly infected with Omicron variants were difficult to recover or even worsen the condition due to old age and underlying diseases. Therefore, by analyzing the various aspects of elderly infected cases, scientific and effective basis can be provided to prevent and control the epidemic situation in the future, and reduce the occurrence of severe, critical and death cases of COVID-19 in the elderly.

Clinical features of COVID-19 Omicron variant cases in makeshift hospital of National Exhibition and Convention Center (Shanghai) / 中国热带医学

@#Objective To summarize and analyze the epidemiological and clinical characteristics of COVID-19 Omicron variant cases in makeshift hospital, and the influence of age, sex and vaccination status on the disease duration, so as to provide reference for the prevention and control of the COVID-19 epidemic. Methods The epidemiological and clinical characteristics of COVID-19 cases admitted to makeshift hospital of National Convention and Exhibition Center (Shanghai) from April 9 to May 31, 2022 were retrospectively described and analyzed, and further cohort analysis was conducted to determine the influence of age, sex and vaccination status on the disease duration of COVID-19 cases in the author's branch hospital. Results Among the 174 466 COVID-19 cases in makeshift hospital, most of them were male, accounting for 59.38%. The infected cases were mainly young and middle-aged people aged 18-59 years old, accounting for 83.50%, followed by 12.30% of the elderly group over 60 years old; the average hospital stay was 7.40 days; the proportion of patients with fever was less than 27.79%; 15.37% (26 817/174 466) of the patients complicated with underlying diseases, and the top three were hypertension, diabetes and coronary heart disease. The proportion of people who received COVID-19 vaccine accounted for 79.56% (13 799/17 956), of which the highest proportion of three doses was 44.09%. The disease duration of 17 956 COVID-19 cases in the author's branch of makeshift hospital was 10.18 (7.34, 13.05) days. The disease duration in the elderly group was the longest with 11.34 (8.35, 14.37) days, followed by 11.17 (9.07, 14.33) days in the preschool group, 10.37 (8.14, 13.34)· days in the middle-aged group, 10.07 (7.37, 12.37) days in the school-age group, and 9.34 (7.05, 12.16) days in the young group. There was significant difference in the overall distribution of disease duration among the five groups (H=550.479 P<0.01). The disease duration in each age group basically showed a V-shaped distribution. The disease duration was 10.27 (7.34, 12.57) days in males and 10.10 (7.25, 13.09) days in females, and there was no significant difference (Z=-1.505 P>0.05). The disease duration of vaccinated patients was 10.24 (7.35, 13.05) days, and that of unvaccinated patients was 9.47 (7.09, 12.47) days. There was significant difference between the two groups (Z=-4.338 P<0.01). Conclusions COVID-19 Omicron variant cases have a high proportion of males, mainly young and middle-aged, and the proportion of fever patients is less than 30%. The disease duration is significantly lower than that of the original strain in Wuhan, and shows "V" distribution with each age group. Sex had no effect on the disease duration. COVID-19 vaccination did not have a clinical effect on the disease duration.

Association between vaccination status and COVID-19-related health outcomes among community-dwelling COVID-19 patients in Nara, Japan

BACKGROUND@#Many previous studies have reported COVID-19 vaccine effectiveness, but there are few studies in Japan. This community-based, retrospective observational study investigated the association between vaccination status and COVID-19-related health outcomes in COVID-19 patients by SARS-CoV-2 variant type.@*METHODS@#The study participants were 24,314 COVID-19 patients aged 12 or older whose diagnoses were reported to the Nara Prefecture Chuwa Public Health Center from April 2021 to March 2022, during periods when the alpha, delta, and omicron variants of COVID-19 were predominant. The outcome variables were severe health consequences (SHC) (i.e., ICU admission and COVID-19-related death), hospitalization, and extension of recovery period. The explanatory variable was vaccination status at least 14 days prior to infection. Covariates included gender, age, population size, the number of risk factors for aggravation, and the number of symptoms at diagnosis. The generalized estimating equations of the multivariable Poisson regression models were used to estimate the adjusted incidence proportion (AIP) and 95% confidence interval (CI) for each health outcome. We performed stratified analyses by SARS-CoV-2 variant type, but the association between vaccination status and COVID-19-related health outcomes was stratified only for the delta and omicron variants due to the small number of vaccinated patients during the alpha variant.@*RESULTS@#Of the 24,314 participants, 255 (1.0%) had SHC; of the 24,059 participants without SHC, 2,102 (8.7%) were hospitalized; and of the 19,603 participants without SHC, hospitalization, and missing data on recovery period, 2,960 (15.1%) had extension of recovery period. Multivariable Poisson regression models showed that regardless of SARS-CoV-2 variant type or health outcome, those who received two or more vaccine doses had significantly lower risk of health outcomes than those who did not receive the vaccine, and there was a dose-response relationship in which the AIP for health outcomes decreased with an increased number of vaccinations.@*CONCLUSION@#A higher number of vaccinations were associated with lower risk of COVID-19-related health outcomes, not only in the delta variant but also in the omicron variant. Our findings suggest that increasing the number of COVID-19 vaccine doses can prevent severe disease and lead to early recovery of patients not requiring hospitalization.

Clinical features of severe acute respiratory syndrome coronavirus 2 Omicron variant infection in children: an analysis of 201 cases / 中国当代儿科杂志

OBJECTIVES@#To study the clinical features of children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection.@*METHODS@#A retrospective analysis was performed on the medical data of 201 children with coronavirus disease 2019 (COVID-19) who were hospitalized and diagnosed with SARS-CoV-2 Omicron variant infection in Quanzhou First Hospital from March 14 to April 7, 2022. Among the 201 children, there were 34 children with asymptomatic infection and 167 with symptomatic infection. The two groups were compared in terms of clinical features, results of experimental examinations, and outcome.@*RESULTS@#Of all the 201 children, 161 (80.1%) had a history of exposure to COVID-19 patients and 132 (65.7%) had a history of COVID-19 vaccination. Among the 167 children with symptomatic infections, 151 had mild COVID-19 and 16 had common COVID-19, with no severe infection or death. Among the 101 children who underwent chest CT examination, 16 had ground glass changes and 20 had nodular or linear opacities. The mean time to nucleic acid clearance was (14±4) days for the 201 children with Omicron variant infection, and the symptomatic infection group had a significantly longer time than the asymptomatic infection group [(15±4) days vs (11±4) days, P<0.05]. The group vaccinated with one or two doses of COVID-19 vaccine had a significantly higher positive rate of IgG than the group without vaccination (P<0.05). The proportions of children with increased blood lymphocyte count in the symptomatic infection group was significantly lower than that in the asymptomatic infection group (P<0.05). Compared with the asymptomatic infection group, the symptomatic infection group had significantly higher proportions of children with increased interleukin-6, increased fibrinogen, and increased D-dimer (P<0.05).@*CONCLUSIONS@#Most of the children with Omicron variant infection have clinical symptoms, which are generally mild. The children with symptomatic infection are often accompanied by decreased or normal blood lymphocyte count and increased levels of interleukin-6, fibrinogen, and D-dimer, with a relatively long time to nucleic acid clearance. Some of them had ground glass changes on chest CT.

Efficacy and Safety of Huashi Baidu Granules in Treating Patients with SARS-CoV-2 Omicron Variant: A Single-Center Retrospective Cohort Study / 中国结合医学杂志

OBJECTIVE@#To evaluate the efficacy and safety of Huashi Baidu Granules (HSBD) in treating patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant.@*METHODS@#A single-center retrospective cohort study was conducted during COVID-19 Omicron epidemic in the Mobile Cabin Hospital of Shanghai New International Expo Center from April 1st to May 23rd, 2022. All COVID-19 patients with asymptomatic or mild infection were assigned to the treatment group (HSBD users) and the control group (non-HSBD users). After propensity score matching in a 1:1 ratio, 496 HSBD users of treatment group were matched by propensity score to 496 non-HSBD users. Patients in the treatment group were administrated HSBD (5 g/bag) orally for 1 bag twice a day for 7 consecutive days. Patients in the control group received standard care and routine treatment. The primary outcomes were the negative conversion time of nucleic acid and negative conversion rate at day 7. Secondary outcomes included the hospitalized days, the time of the first nucleic acid negative conversion, and new-onset symptoms in asymptomatic patients. Adverse events (AEs) that occurred during the study were recorded. Further subgroup analysis was conducted in vaccinated (378 HSBD users and 390 non-HSBD users) and unvaccinated patients (118 HSBD users and 106 non-HSBD users).@*RESULTS@#The median negative conversion time of nucleic acid in the treatment group was significantly shortened than the control group [3 days (IQR: 2-5 days) vs. 5 days (IQR: 4-6 days); P<0.01]. The negative conversion rate of nucleic acid in the treatment group were significantly higher than those in the control group at day 7 (91.73% vs. 86.90%, P=0.014). Compared with the control group, the hospitalized days in the treatment group were significantly reduced [10 days (IQR: 8-11 days) vs. 11 days (IQR: 10.25-12 days); P<0.01]. The time of the first nucleic acid negative conversion had significant differences between the treatment and control groups [3 days (IQR: 2-4 days) vs. 5 days (IQR: 4-6 days); P<0.01]. The incidence of new-onset symptoms including cough, pharyngalgia, expectoration and fever in the treatment group were lower than the control group (P<0.05 or P<0.01). In the vaccinated patients, the median negative conversion time and hospitalized days were significantly shorter than the control group after HSDB treatment [3 days (IQR: 2-5 days) vs. 5 days (IQR: 4-6 days), P<0.01; 10 days (IQR: 8-11 days) vs. 11 days (IQR: 10-12 days), P<0.01]. In the unvaccinated patients, HSBD treatment efficiently shorten the median negative conversion time and hospitalized days [4 days (IQR: 2-6 days) vs. 5 days (IQR: 4-7 days), P<0.01; 10.5 days (IQR: 8.75-11 days) vs. 11.0 days (IQR: 10.75-13 days); P<0.01]. No serious AEs were reported during the study.@*CONCLUSION@#HSBD treatment significantly shortened the negative conversion time of nuclear acid, the length of hospitalization, and the time of the first nucleic acid negative conversion in patients infected with SARS-COV-2 Omicron variant (Trial registry No. ChiCTR2200060472).

Clinical characteristics of neonates infected with the Omicron variant of SARS-CoV-2: a multicenter cross-sectional survey / 中国当代儿科杂志

OBJECTIVES@#To investigate the clinical characteristics of neonates infected with the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).@*METHODS@#A cross-sectional survey was conducted on 542 hospitalized neonates with confirmed coronavirus disease 2019 (COVID-19) in 27 hospitals in Shenzhen from December 7, 2022, to January 12, 2023 (during the Omicron variant epidemic period). The neonates were divided into two groups: asymptomatic infection and symptomatic infection. The clinical characteristics, results of laboratory examination, chest X-ray findings, and outcome were compared between the two groups.@*RESULTS@#Among the 542 neonates, there were 285 males and 257 females. Among them, 515 (95.0%) were full-term infants, and 27 (5.0%) were preterm infants. The asymptomatic infection group had 60 cases, and the symptomatic infection group had 482 cases. Among them, 336 cases (69.7%) were mild, 125 cases (25.9%) were moderate, 15 cases (3.1%) were severe, and 6 cases (1.2%) were critical. Fever was the most common symptom (434 cases, 90.0%), followed by cough and/or spitting (183 cases, 38.0%), nasal congestion and/or runny nose (131 cases, 27.2%), shortness of breath (36 cases, 7.5%), and feeding intolerance (30 cases, 6.2%). Among the 325 cases who underwent chest X-ray examination, 136 cases (41.8%) had patchy or consolidative shadows in the lungs, 2 cases (0.6%) had pneumothorax, 2 cases (0.6%) had decreased lung transparency, and 185 cases (57.0%) showed no abnormality. Among the 396 cases (73.1%) who received treatment, 341 cases (86.1%) received symptomatic treatment, 137 cases (34.6%) received antibiotic treatment, 4 cases (1.0%) received immunoglobulin treatment, and 23 cases (5.8%) received respiratory support treatment. All 542 neonates were discharged from the hospital after their clinical symptoms were relieved, and the median hospital stay was 5 days. The white blood cell count, neutrophil count, hemoglobin, and procalcitonin were lower in the symptomatic infection group than those in the asymptomatic infection group (P<0.05), while the platelet count and blood glucose levels were higher in the symptomatic infection group than those in the asymptomatic infection group (P<0.05). The proportions of neonates with decreased neutrophil count, increased platelet count, and decreased hemoglobin concentration were higher in the symptomatic infection group than those in the asymptomatic group (P<0.05).@*CONCLUSIONS@#Most neonates with COVID-19 caused by the Omicron variant of SARS-CoV-2 are mild, with fever as the predominant symptom. Symptomatic neonates with COVID-19 are often accompanied by decreased neutrophil count, increased platelet count, and decreased hemoglobin level. Symptomatic treatment is the main treatment, and the prognosis is good.

Clinical features of children with coronavirus disease 2019 in different age groups during the epidemic of Omicron variant / 中国当代儿科杂志

OBJECTIVES@#To study the differences in the clinical features of children with coronavirus disease 2019 (COVID-19) in different age groups during the epidemic of Omicron variant.@*METHODS@#A retrospective analysis was performed on the clinical data of 211 children with COVID-19 who were admitted to the Department of General Pediatrics, Zhongshan People's Hospital, from December 9, 2022 to January 8, 2023. According to their age, they were divided into 4 groups: 1 month-<1 year (n=84), 1-<3 years group (n=64), 3-<5 years (n=29), and ≥5 years (n=34). The above groups were compared in terms of general status, clinical features, ancillary examination results, treatment, and outcome.@*RESULTS@#The children aged <3 years accounted for 70.1% (148/211) of all hospitalized children with COVID-19, and the 3-<5 years group and the ≥5 years group had a significantly higher proportion of children with underlying diseases than the 1 month-<1 year group and the 1-<3 years group (P<0.05). Compared with the other three groups, the 1 month-<1 year group had significantly higher incidence rates of dyspnea, nasal congestion/nasal discharge, diarrhea and significantly lower incidence rates of convulsion and nervous system involvement (P<0.05). Moreover, compared with the other three groups, the 1 month-<1 year group had significantly higher incidence rates of increases in bile acid and creatine kinase isoenzyme and significantly lower incidence rates of decreased platelet count, increased neutrophil percentage, and decreased lymphocyte percentage (P<0.05). The 1 month-<1 year group had a significantly higher incidence rate of mild COVID-19 than the 1-<3 years group and a significantly lower incidence rate of severe/critical COVID-19 than the other three groups (P<0.05). Compared with the other three groups, the 1 month-<1 year group had a significantly higher proportion of children receiving oxygen inhalation therapy (P<0.05).@*CONCLUSIONS@#Children with COVID-19 in different age groups have different clinical features during the epidemic of Omicron variant, especially between the children aged 1 month to <1 year and those aged ≥1 year.

Clinical features of children with febrile seizures caused by Omicron variant infection / 中国当代儿科杂志

OBJECTIVES@#To study the clinical features of children with febrile seizures after Omicron variant infection.@*METHODS@#A retrospective analysis was performed on the clinical data of children with febrile seizures after Omicron variant infection who were admitted to the Department of Neurology, Children's Hospital Affiliated to the Capital Institute of Pediatrics, from December 1 to 31, 2022 (during the epidemic of Omicron variant; Omicron group), and the children with febrile seizures (without Omicron variant infection) who were admitted from December 1 to 31, in 2021 were included as the non-Omicron group. Clinical features were compared between the two groups.@*RESULTS@#There were 381 children in the Omicron group (250 boys and 131 girls), with a mean age of (3.2±2.4) years. There were 112 children in the non-Omicron group (72 boys and 40 girls), with a mean age of (3.5±1.8) years. The number of children in the Omicron group was 3.4 times that in the non-Omicron group. The proportion of children in two age groups, aged 1 to <2 years and 6-10.83 years, in the Omicron group was higher than that in the non-Omicron group, while the proportion of children in two age groups, aged 4 to <5 years and 5 to <6 years, was lower in the Omicron group than that in the non-Omicron group (P<0.05).The Omicron group had a significantly higher proportion of children with cluster seizures and status convulsion than the non-Omicron group (P<0.05). Among the children with recurrence of febrile seizures, the proportion of children aged 6-10.83 years in the Omicron group was higher than that in the non-Omicron group, while the proportion of children aged 3 years, 4 years, and 5 years in the Omicron group was lower than that in the non-Omicron group (P<0.05).@*CONCLUSIONS@#Children with febrile seizures after Omicron variant infection tend to have a wider age range, with an increase in the proportion of children with cluster seizures and status convulsion during the course of fever.