ObjectiveTo analyze the evolutionary characteristics and genetic variations of the HA (hemagglutinin) and NA (neuraminidase) genes of influenza A(H1N1) viruses in Shanghai during 2024, to investigate their transmission patterns, and to evaluate their potential impact on vaccine effectiveness. MethodsFrom January to October 2024, throat swab specimens were collected from influenza like illness (ILI) patients at 4 hospitals in Shanghai. Real-time fluorescence ploymerase chain reaction (RT-PCR) was used for virus detection and isolation of H1N1 influenza viruses. Forty influenza A(H1N1) virus strains were sequenced using Illumina NovaSeq 6000 platform, followed by phylogenetic analyses, genetic distance analysis, and amino acid variation analyses of HA and NA genes. ResultsPhylogenetic tree of the HA and NA genes revealed that the 40 influenza A(H1N1) virus strains circulating in Shanghai in 2024 exhibited no significant geographic clustering, with a broad origin of strains and complex transmission chains. Genetic distance analyses demonstrated that the average intra-group genetic distances of HA and NA genes among the Shanghai strains were 0.005 1±0.000 6 and 0.004 6±0.000 6, respectively, which were comparable to or higher than those observed in global surveillance strains. Both HA and NA genes displayed frequent mutations. Compared to the 2023‒2024 and 2024‒2025 Northern Hemisphere A(H1N1) vaccine strains (WHO-recommended), the HA proteins of 40 Shanghai strains exhibited amino acid substitutions at positions 120, 137, 142, 169, 216, 223, 260, 277, 356 and 451, with critical mutations at positions 137 and 142 located within the Ca2 antigenic determinant. Furthermore, mutations in the NA protein were observed at positions 13, 50, 200, 257, 264, 339 and 382. ConclusionThe genetic background of the 2024 Shanghai influenza A(H1N1) virus strains is complex and diverse, and antigenic variation may affect vaccine effectiveness. Therefore, it is recommended to enhance genomic surveillance of influenza viruses, evaluate vaccine suitability, and implement more targeted prevention and control strategies against imported influenza viruses.

Objective:To investigate the feasibility of predicting the risk of spontaneous preterm birth in singleton pregnancy women with low risk of preterm birth by transabdominal-transvaginal ultrasound cervical length sequential screening in the second trimester.Methods:This prospective longitudinal cohort study included singleton pregnant women at 11-13 +6 gestational weeks who were admitted to Nanjing Drum Tower Hospital from January 2023 to September 2023. Transabdominal and transvaginal cervical lengths were measured during the mid-trimester fetal ultrasound scan at 18-24 weeks, and pregnancy outcomes were obtained after delivery. A short cervix was defined as a transvaginal cervical length of ≤25 mm, and the outcomes were defined as spontaneous preterm birth occurs between 20 and 36 +6 weeks and extremely preterm birth before 32 weeks. The area under the receiver operating characteristic (ROC) curve was used to evaluate the effectiveness of predicting spontaneous preterm birth by transabdominal and transvaginal cervix length, as well as the effectiveness of predicting short cervix by transabdominal cervical length. The relationship between transabdominal and transvaginal cervical length was evaluated using a scatter plot. Results:A total of 562 cases were included in this study, comprising 33 cases of spontaneous preterm birth (7 cases occurring before 32 weeks) and 529 cases of term birth. (1) Compared to the term birth group, transabdominal cervical length (median: 37.6 vs 33.2 mm; Z=-3.838, P<0.001) and transvaginal cervical length (median: 34.0 vs 29.9 mm, Z=-3.030, P=0.002) in the spontaneous preterm birth group were significantly shorter. (2) The areas under the ROC curve for predicting spontaneous preterm birth by transabdominal and transvaginal cervical length were 0.699 (95% CI: 0.588-0.809) and 0.657 (95% CI: 0.540-0.774), respectively. The sensitivity, specificity and positive predictive value of transvaginal cervical length Conclusions:In singleton pregnancy women with low risk of preterm birth, transabdominal-transvaginal cervical length sequential screening can reduce unnecessary transvaginal ultrasounds by approximately 41% without missing the diagnosis of pregnant women with a short cervix. This method also enhances the effectiveness of transvaginal cervical length to spontaneous preterm birth.

Objective:To investigate the clinical characteristics of cases with different congenital pulmonary airway malformations (CPAM) volume ratios (CVR) and the effect of maternal glucocorticoid treatment during pregnancy on CPAM.Methods:A retrospective study was conducted on 56 singleton pregnant women with fetal CPAM diagnosed prenatally in the Department of Obstetrics and Gynecology at Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, from September 2020 to May 2023. Among these, three cases received maternal glucocorticoid treatment during pregnancy and clinical conditions were reported in detail. Statistical analyses were performed using independent sample t-tests, non-parametric tests, Chi-square tests, or Fisher's exact test. Results:(1) General information: The average age of the 56 pregnant women with CPAM fetuses was (32.0±0.7) years. All fetuses had unilateral lesions, with 25 cases (44.6%) on the left side. Types Ⅰ, Ⅱ, and Ⅲ CPAM accounted for 5.4% (3/56), 50.0% (28/56), and 44.6% (25/56), respectively. Fetal hydrops occurred in two cases, and the maximum CVR during the fetal period for the other 54 non-hydropic fetuses was 0.79±0.66. (2) The CVR threshold for the risk of fetal hydrops was set as the mean maximum CVR of non-hydropic CPAM fetuses plus 2 standard deviations (0.79+2×0.66=2.1). The subjects were divided into two groups based on the maximum CVR during the fetal period: CVR≤2.0 group ( n=50) and CVR>2.0 group ( n=6). Comparison between the CVR>2.0 group and CVR≤2.0 group: The CVR>2.0 group had significantly higher rates of fetal hydrops [2/6 vs. 0.0% (0/50), Fisher's exact test], mediastinal shift [5/6 vs. 32.0% (16/50), χ 2=4.03], polyhydramnios [6/6 vs. 4.0% (2/50), Fisher's exact test], and postnatal surgery [4/5 vs. 22.2% (10/45), continuity correction χ 2=4.86] (all P<0.05). None of the fetuses with CVR≤2.0 had hydrops or received intrauterine intervention. The overall live birth rate was 89.3% (50/56). (3) Maternal glucocorticoid treatment during pregnancy: three of six fetuses with CVR>2.0 were treated with maternal glucocorticoid during pregnancy, and all were delivered alive at term after the intervention with resolution of edema and/or reduction in mass size. Two of them were treated with postnatal thoracoscopic surgery and were followed up to 5 and 14 months of age, respectively, with no abnormalities in feeding and development; the other was not treated surgically until 3 months of age, with no respiratory-related symptoms and no abnormalities in feeding and development. Conclusions:Prenatal ultrasound indicating CVR>2.0 is associated with increased rates of fetal hydrops, mediastinal shift, and polyhydramnios. Maternal glucocorticoid treatment during pregnancy may lead to favorable pregnancy outcomes for these CPAM fetuses.

Objective:To investigate the effectiveness and prognosis of using improved domestic neonatal ureteral stents (referred to as improved double-J stents) for thoraco-amniotic shunting (TAS) in treating fetal chylothorax.Methods:A retrospective analysis was conducted on the clinical data of 21 cases of fetal chylothorax treated with TAS using improved double-J stents at Nanjing Drum Tower Hospital, Nanjing University Medical School from April 1, 2018, to September 30, 2023. Surgical complications and perinatal outcomes were summarized, and the development of surviving infants in five domains (communication, gross motor, fine motor, problem-solving, and personal-social) was assessed using the Ages and Stages Questionnaires-Third Edition (ASQ-3). Descriptive statistical analysis was used. Results:(1) The median gestational age at prenatal diagnosis was 28.7 weeks (27.3-30.4 weeks), with 85.7% (18/21) of cases complicated by fetal hydrops, 90.5% (19/21) by polyhydramnios, and 85.7% (18/21) by bilateral pleural effusion. (2) The median gestational age at the first TAS was 30.9 weeks (29.7-32.7 weeks). Of the 21 cases, 10 required repeat stent placement due to dislodgement or blockage, with a total of 49 stent placements. The dislodgement rate within 7 days was 24.5% (12/49), and the blockage rate was 16.3% (8/49). The rate of premature rupture of membranes within one week post-stent placement was 9.5% (2/21), with an overall preterm premature rupture of membranes rate of 28.6% (6/21). The median interval from the first TAS to delivery was 30.0 d (19.8-40.0 d). Of the 21 cases, three opted for selective termination of pregnancy; the remaining 18 cases resulted in live births, with a median gestational age at delivery of 35.6 weeks (34.1-37.1 weeks), and three neonatal deaths. The overall neonatal survival rate was 15/18. Surviving infants were followed up to a median age of 30 months (7-48 months), with 13 showing normal development and two scoring below the ASQ-3 threshold.Conclusion:The improved double-J stent can be used for TAS in the treatment of fetal chylothorax, with generally favorable outcomes.

ObjectiveTo predict the incidence trend of influenza-like illness proportion （ILI%） in Shanghai using the seasonal autoregressive integrated moving average model （SARIMA）， and to provide an important reference for timely prevention and control measures. MethodsTime series analysis was performed on ILI% surveillance data of Shanghai Municipal Center for Disease Control and Prevention from the 15^th week of 2015 to the 52^nd week of 2019， and a prediction model was established. Seasonal autoregressive integrated moving average （SARIMA） model was established using data from the foregoing 212 weeks， and prediction effect of the model was evaluated using data from the latter 36 weeks. ResultsFrom the 15^th week of 2015 to the 52^nd week of 2019， the average ILI% in Shanghai was 1.494%， showing an obvious epidemic peak. SARIMA（1，0，0） （2，0，0） ₅₂ was finally modeled. The residual of the model was white noise sequence， and the true values were all within the 95% confidence interval of the predicted values. ConclusionSARIMA（1，0，0） （2，0，0） ₅₂ can be used for the medium term prediction of ILI% in Shanghai， and can play an early warning role for the epidemic and outbreak of influenza in Shanghai.

Objective:To explore the clinical significance of cervical length (CL) measured by transabdominal ultrasound during fetal structural anomalies screeing at 20-24 +6 weeks of gestation. Methods:This was a retrospective nested case-control study based on a prospective longitudinal cohort of "Prediction and Prevention of Early-onset Preeclampsia", which recruited 4 995 singleton pregnant women at the gestational age of 11-13 +6 weeks in Nanjing Drum Tower Hospital from April 2019 to August 2022. All the subjects underwent second-trimester ultrasound screening for fetal structural anomalies in our hospital with image records. This study excluded the women who were lost to follow-up, underwent cervical cerclage, terminated the pregnancy due to personal or social factors, or had miscarriage before 20 weeks of gestation, and those with iatrogenic preterm births, intrauterine fetal death or no second-trimester cervical sonography images. Propensity score matching was used to match pregnant women with spontaneous preterm birth ( n=101) and those with full-term delivery ( n=101) in a 1∶1 ratio, with factors of maternal age, body mass index, preterm birth history, cesarean section history, and pregnancy interval ≥5 years. CL was measured based on the retained ultrasound images. Nonparametric test or Chi-square test were used for statistical analysis. Receiver operating characteristic (ROC) curve was used to evaluate the correlation between CL measured by transabdominal ultrasound in the second trimester and spontaneous preterm birth. Results:The CL measured by transabdominal ultrasound at 20-24 +6 weeks of gestation was significantly shorter in the spontaneous preterm birth group than that in the full-term group [2.8 cm (2.5-3.3 cm) vs. 3.4 cm (3.0-3.9 cm), Z=－5.85, P<0.001]. If CL<3.4 cm was used as the cut-off value for predicting spontaneous preterm birth (20-36 +6 weeks), the specificity and the sensitivity were 0.50 and 0.77, respectively, and the sensitivity reached 0.92 for predicting preterm birth before 32 weeks and 1.00 for predicting preterm birth before 28 weeks. If CL<3.7 cm was used as the cut-off value, the specificity and the sensitivity were 0.36 and 0.87, respectively, and the sensitivity was 1.00 for predicting preterm birth before 32 weeks. The efficacy of preterm birth screening at 28-36 +6 weeks of gestation was comparable to that at 20-36 +6 weeks, if CL<3.4 cm and CL<3.7 cm were used as the cut-off value, the sensitivity were 0.76 and 0.86, respectively. Conclusion:Transabdominal ultrasound measurement of CL in the second trimester can be a preliminary screening to determine whether further transvaginal ultrasound measurement of CL is needed for women without a history of preterm birth or late spontaneous abortion.

Objective:To evaluate the performance of the influenza surveillance network and compare the epidemic intensity of influenza during 2014-2020 in Shanghai.Methods:Based on the weekly reports of influenza-like illness (ILI) and laboratory-confirmed influenza cases from January 1, 2014 to December 31, 2020. This study first evaluated the data reporting and specimen collection of ILI cases for each sentinel hospital, and then calculated the percentage of ILI (ILI%), the proportion of specimens tested positive for influenza, and the incidence of influenza among all ILI outpatient and emergency visits to measure the epidemic intensity of influenza. Finally, seasonal autoregressive integrated moving average (ARIMA) model was applied to quantify the changes in epidemic intensity of influenza in 2020.Results:The proportion of influenza surveillance sentinel hospitals with a score of less than 5 in the evaluation of ILI data reporting and samples collection were 9.68% and 21.05% in 2020 in Shanghai, respectively. ILI% was estimated to be 1.51% (95% CI: 1.50%-1.51%) and 2.31% (95% CI: 2.30%-2.32%), respectively for 2014-2019 and 2020; the proportion of specimens tested positive was 24.27% (95% CI: 24.02%- 24.51%) and 7.15% (95% CI: 6.78%-7.54%), respectively; and the incidence of influenza was 3.66‰ (95% CI: 3.62‰-3.70‰) and 1.65‰ (95% CI: 1.57‰-1.74‰), respectively. ARIMA model showed that ILI% was increased by 45.25% in 2020 in Shanghai, and the proportion of specimens tested positive and the incidence of influenza were reduced by 78.45% and 51.80%, respectively. Conclusions:In 2020, the performance of influenza surveillance system has changed, ILI% has increased, the proportion of specimens tested positive and the incidence of influenza has decreased in Shanghai. The change in the quality of influenza surveillance is also a potential factor affecting the epidemic intensity of influenza. In the future, the quality control of influenza surveillance network still needs to be further strengthened.

Objective:To study the infection status and epidemiological characteristics of parainfluenza virus (PIV) in acute respiratory tract infection adult cases in Shanghai from 2015 to 2021, and to provide a scientific basis for preventing and controlling PIV.Methods:Acute respiratory tract infections were collected from 13 hospitals in Shanghai from 2015 to 2021. Relevant information was registered, and respiratory specimens were sampled to detect respiratory pathogens by multiplex PCR.Results:A total of 5 104 adult acute respiratory tract infection cases were included; the overall positive rate of the respiratory pathogens was 29.37% (1 499/5 104). The positive rate of PIV was 2.61% (133/5 104), compared with 2.32% (55/2 369) and 2.85% (78/2 735) in influenza-like cases (ILI) and severe acute respiratory infection (SARI) cases, respectively. Among them, PIV3 accounted for the highest proportion (62.41%, 83/133), followed by PIV1 (18.80%, 25/133), PIV2 (9.77%, 13/133), and PIV4 (9.02%, 12/133). The incidence of PIV-positive cases was mainly distributed in the first and second quarters, accounting for 62.41% (83/133). The difference in the incidence in each quarter was significant ( χ2=24.78, P<0.001). Mixed infection accounted for 18.80% (25/133) of 133 PIV-positive cases, the mixed infection rates of ILI and SARI were 18.18% (10/55) and 19.23% (15/78), respectively, and the main mixed pathogen of PIV was coronavirus 229E. Conclusions:There are a certain proportion of PIV-positive acute respiratory tract infection cases in Shanghai. It is necessary to strengthen the etiological surveillance in acute respiratory tract infection cases, especially the mixed infection of PIV and other pathogens.

Objective:To analyze the changes in the epidemiological characteristics of scarlet fever cases in Shanghai City before and after the outbreak of coronavirus disease 2019 (COVID-19), and to provide a reference for scientific prevention and control of scarlet fever.Methods:The information of scarlet fever reported cases in Shanghai City from January 2016 to June 2021 in the information system of Chinese Disease Prevention and Control was collected, and the differences in time trend, regional distribution, age and gender distribution of cases before and after the outbreak of COVID-19 in Shanghai City were analyzed by descriptive epidemiologic method.Results:The incidence rate of scarlet fever reported in 2016-2019 was (0.22-4.02)/100 000 in each month, with a median of 1.13/100 000. During January 2020 (the outbreak began in Shanghai City) and June 2021, the incidence rate of scarlet fever was (0.01-1.64)/100 000, with a median of 0.14/100 000, which was 12.39% of that before the outbreak of COVID-19. During February and June 2020, the monthly reported incidence rate of scarlet fever was (0.18-0.58)/100 000, showing an upward trend compared with the same period in 2020 ((0.01-0.05)/100 000). From 2016 to 2019, the annual reported incidence rate of each district was (0.55-65.48)/100 000, with a median of 9.57/100 000; while in 2020, the annual reported incidence rate of each district was (0.29-9.85)/100 000, with a median of 2.18/100 000, which was 22.78% of that before the outbreak of COVID-19. The incidence of scarlet fever dropped significantly. The incidence rate in Minhang District was still the highest. The cases were mainly four to eight years old, and there was no substantial difference of the proportions before and after COVID-19 pandemic, with the incidence rate of six years old group the highest. The proportion of male was more than female in reported case, while the male ratio in reported cases was not significantly different before and after COVID-19 pandemic.Conclusions:The incidence rate of scarlet fever in Shanghai City has dropped sharply after COVID-19 pandemic. The main epidemiological characteristics of the regional and population distribution of cases remain unchanged.

Objective:To study the epidemiological characteristics and mixed infection of adenovirus in acute respiratory tract infections in Shanghai from 2015 to 2019, and to provide scientific basis for the prevention and control of adenovirus.Methods:Acute respiratory tract infections were collected from 3 hospitals in Shanghai from 2015 to 2019. Relevant information was registered and respiratory specimens were sampled for detection of respiratory pathogens by multiplex PCR.Results:A total of 1 543 cases of acute respiratory tract infection were included. The positive rate of adenovirus was 2.92%(45/1 543), the positive rates of influenza like illness (ILI) and severe acute respiratory illness (SARI) were 2.74%(29/1 058) and 3.30%(16/485), respectively. The positive rate of ILI during January-May 2019 was 5.43%(7/129), higher than that in the same period of 2015- 2018 (0.52%-4.48%) (Fisher’s exact test value=8.92, P=0.036). The incidence of adenovirus-positive cases was mainly distributed in the first and second quarters, accounting for 62.22% (28/45). The difference of the incidence of adenovirus-positive cases in each quarter was significant ( χ2= 12.52, P=0.006). The positive rate in the second quarter was highest (6.03%), which was higher than that in other quarters (1.89%-2.93%). There were significant differences among different age groups ( χ2=16.94, P=0.001), and the positive rate decreased with age ( χ2=10.16, P=0.001). The positive rate of 13-19 years old group (9.43%) was higher than that of other age groups (1.48%-4.81%). The positive rate of student group (12.07%) was higher than that of other occupations (2.61%). The difference was systematic ( χ2=11.53, P=0.001). Mixed infection accounted for 31.11% (14/45) of 45 adenovirus positive cases. The mixed infection rates of ILI and SARI were 34.48% (10/29) and 25.00% (4/16), respectively. Among 14 cases of mixed infection, the main mixed infection pathogens of adenovirus were influenza A virus and coronavirus. Conclusion:Adenovirus surveillance should be further strengthened in adolescents with a focus on students and other key groups in the second quarter.