Objective:To analyze the epidemiological characteristics of reinfection of 2019-nCoV and influencing factors, and provide evidence for effective prevention and control of COVID-19 epidemic.Methods:The incidence data of COVID-19 in Ningbo from January 1, 2020 to November 30, 2022 were collected from the infectious disease surveillance system of Chinese information system for disease control and prevention. The incidence of reinfection of 2019-nCoV was investigated by using questionnaire. logistic regression analysis was used to analyze the influences of gender, age, time interval from the first infection, history of underlying disease, 2019-nCoV vaccination dose and disease severity on the reinfection.Results:A total of 897 previous 2019-nCoV infection cases were investigated, of which 115 experienced the reinfection of 2019-nCoV, the reinfection rate was 12.82%. The interval between the two infections M( Q1, Q3) was 1 052 (504, 1 056) days. Univariate analysis showed that age, 2019-nCoV vaccination dose, history of underlying disease, type of 2019-nCoV variant causing the first infection, time interval from the first infection and severity of the first infection were associated with the reinfection rate (all P<0.05). Multivariate logistic regression analysis showed that the risk for reinfection in age group 30- years was higher than that in age group ≥60 years ( OR=2.10, 95% CI: 1.11-3.97). No reinfection occurred in those with time interval from the first infection of <6 months, and the risk for reinfection was higher in those with the time interval of ≥12 months than in those with the time interval of 6- months ( OR=6.68, 95% CI: 3.46-12.90). The risk for reinfection was higher in the common or mild cases than in the asymptomatic cases ( OR=2.64, 95% CI: 1.18-5.88; OR=2.79, 95% CI: 1.27-6.11). Conclusion:The time interval from the first infection was an important influencing factor for the reinfection of 2019-nCoV, and the probability of the reinfection within 6 months was low.

Objective: To investigate the origin of infection and risk factors of a case with SARS-CoV-2 infection associated with overseas countries in the Ningbo-Zhoushan Port, Zhejiang Province, so as to provide the evidence for improving the COVID-19 control measures at ports. Methods: Ningbo Center for Disease Control and Prevention ( CDC ) and Beilun CDC conducted case finding and epidemiological surveys immediately after being informed. The general information, history of vaccination and the travel during the latest 14 days were collected from the positive case, and all close contacts were tracked. Saliva samples were collected for SARS-CoV-2 nucleic acid testing and whole-genome sequencing, and the sequencing results were aligned with the GISAID's EpiCoV database. The origin of infection and transmission route of the positive case was investigated. Results: A case was identified positive for SARS-CoV-2 nucleic acid during company M's routine screening in the Ningbo-Zhoushan Port on August 10, 2021, and was confirmed positive for SARS-CoV-2 nucleic acid by Beilun CDC and Ningbo CDC on August 11. Whole-genome sequencing showed SARS-CoV-2 B.1.617.2 ( Delta ) variant, which shared the highest homology with the virus sequence uploaded by Russia on June, 2021 ( Russia/MOW-RII-MH27356S/2021 ). The case was a bundling worker for overseas container ships, and reported communicated with foreign boatmen and contacted materials without protected interventions on the SINOKOR AKITA Container Ship between August 4 and 5, 2021. This ship anchored at Vladivostok, Russia from July 27 to 29, anchored at Ningbo Harbor on August 4, and departed on August 5. Then, 11 boatmen from this ship were tested positive for SARS-CoV-2 nucleic acid on August 8. One asymptomatic case was reported in this epidemic; 254 close contacts and 617 secondary close contacts were identified, and all were tested negative for SARS-CoV-2 nucleic acid. No new cases with SARS-CoV-2 infections were detected until August 25, 2021, and the emergency response was therefore terminated. Conclusions The infection was a sporadic COVID-19 epidemic associated with overseas countries, which was caused by Delta variant infection through contacts with foreign boatmen or materials by a bundling worker in Ningbo-Zhoushan Port; fortunately, no epidemic spread occurred. Intensified closed-loop management and increased frequency of SARS-CoV-2 nucleic acid test among high-risk populations, and improving the precision and rapid emergency treatment of COVID-19 epidemics are required for the containment of COVID-19 at ports.

Objective:To understand the seroepidemiological characteristics of pertussis in healthy population in Ningbo, and estimate the overall incidence of pertussis.Methods:A cross-sectional survey method was used in this study. A total of 1 206 healthy residents in 9 age groups were stratified randomly selected from 3 counties of Ningbo. Serum samples were collected from the subjects, and the pertussis toxin immunoglobulin G antibody (PT-IgG) levels were measured quantitatively by enzyme-linked immunosorbent assay (ELISA).Results:The mean PT-IgG seropositive rate in the subjects was 0.91% (95% CI:0.45%-1.63%) with a geometric mean titer (GMT) of 3.10 (95% CI:2.86-3.36) IU/ml. The seropositive rates ranged from 0.00% to 1.68%, and the GMTs ranged from 2.08 IU/ml to 5.28 IU/ml in 9 age groups. The incidence rate of pertussis was estimated to be 4 572.81 per 100 000 in age group ≥5 years (95% CI:1 807.30 per 100 000-9 348.12 per 100 000), and the peak of estimated incidence rates were found in age group 5- years (9 301.62 per 100 000, 95% CI:1 121.77 per 100 000-33 154.68 per 100 000) and age group ≥50 years old (8 967.02 per 100 000, 95% CI: 1 059.45 per 100 000-31 845.94 per 100 000). Conclusions:The actual incidence of pertussis was high in Ningbo in 2019. As a result of waning immunity after vaccination, pertussis can occur in adolescents and adults. The pertussis surveillance should be strengthened and the pertussis vaccination strategy should be improved.

Objective: To analyze the epidemiological characteristics of coronavirus disease 2019 （COVID-19） cases reported in Ningbo from January 22 to February 22, 2020, so as to provide guidance for the prevention and control of the COVID-19 epidemic. Methods: The confirmed cases of COVID-19 reported by Ningbo were selected from National Diseases Prevention and Control Information System to analyze the epidemiological characteristics by descriptive epidemiological method, including time, spatial and population distribution, clinical symptoms and exposure history. Results: A total of 157 confirmed cases of COVID-19 were reported and there was no death. The first confirmed case was reported on January 22. On the incidence curve, the peak was from January 22 to February 4, with a maximum of 15 cases in a single day. The incidence curve presented sustained human-to-human transmission. The number of the cases showed a declining trend from February 5. The confirmed cases were reported in all 10 counties（cities or districts）,among which 69（43.95%）cases were reported in Haishu District. The confirmed cases were mainly 30-69 years old,accounting for 78.34%;were mainly farmers,household workers and retired people,accounting for 59.87%;and were mainly clinically mild,accounting for 87.90%.There were 51 imported cases, accounting for 32.48%. The initial confirmed case was a local case. In the early stage of the epidemic, local cases and imported cases prevalent together,which was due to the outbreak caused by the large-scale buddhist activity on January 19.This event resulted in 67 confirmed cases and 15 asymptomatic cases. There totally reported 22 clusters with 138 （87.90%）confirmed cases. Conclusions In the early stage of the COVID-19 epidemic in Ningbo, the imported cases and local cases prevalent at the same time. Most of the cases were female, aged from 30 to 69 years, and their occupation were farmers, household workers and retired people. With comprehensive measures taken, the epidemic of COVID-19 in Ningbo have been under control.

Objective To investigate the clinical significance of combined heart and lung ultrasound in patients with severe left heart failure and pulmonary hypertension. Methods From March 2016 to June 2017, 75 patients with grade Ⅲ and Ⅳ heart failure and dyspnea were enrolled in Qingdao Municipal Hospital Affiliated to Qingdao University. Thirty-three patients had normal pulmonary artery pressure (normal pulmonary arterial pressure group), 25 patients had mild pulmonary hypertension (mild pulmonary hypertension group), and 17 patients had moderate to severe pulmonary hypertension (moderate to severe pulmonary hypertension group). The patient′s plasma B-type natriuretic peptide (BNP) was measured. Left ventricular diameter (LVD), right ventricular diameter (RVD), and left ventricular ejection fraction (LVEF) were measured by echocardiography. The patient′s lungs were observed by lung ultrasonography, and its number was recorded. One-way analysis of variance was used to compare the differences of LVD, RVD, and LVEF in three groups of patients with severe left heart failure. Further comparison between groups was performed using LSD-t test. Kruskal-wallis H test was used to compare the plasma BNP concentration and B-line number in three groups of patients with severe left heart failure. The Mann-Whitney U test was used to further compare the groups. The receiver operating characteristic (ROC) curve of pulmonary hypertension diagnosed by plasma BNP concentration and B line number in patients with severe left heart failure were drwan. Results The concentrations of BNP in patients with normal pulmonary arterial pressure, mild pulmonary hypertension, and moderate to severe pulmonary hypertension were 890 (614, 1516), 1460 (1245, 1950), and 2660 (1670, 3279) ng/L, respectively. The number of B line was 12 (9, 16), 17 (14, 18), 26 (20, 28), and the RVD was (22.1±1.7), (24.9±2.0), (26.3±2.8) mm, respectively. The number of B-line and RVD in the moderate-severe pulmonary hypertension group were both lager than those in the mild pulmonary hypertension group, and the number of B-line and RVD in the mild pulmonary hypertension group were both lager than those in the normal pulmonary artery pressure group. There was significant difference between any two groups (BNP concentration: U=210.500, P < 0.05; U=47.000, 73.000, both P < 0.001;B line number:U=189.000,P < 0.05;U=38.5000,64.000,both P < 0.001;RVD:t=0.553, 0.623, both P<0.001; t=0.656, P<0.05). There was no significant difference in LVD and LVEF between the three groups of patients. The ROC curve showed that the optimal threshold for the diagnosis of pulmonary hypertension in patients with severe left heart failure with BNP concentration was 1225 ng/L. The sensitivity was 85.7%,the specificity was 69.7%,the area under the curve was 0.814,and the 95% CI was 0.717 to 0.911. The optimal threshold for diagnosis of pulmonary hypertension in patients with severe left heart failure was B line number 14, the sensitivity was 88.1%, specificity was 66.7%, the area under the curve was 0.836, and 95%CI was 0.747 to 0.925.Conclusion Patients with severe left heart failure at different pulmonary artery pressure levels have different B-line findings, and the number of B-line increases with the severity of pulmonary hypertension, which warrants further study and application.

Objective To evaluate efficacy of thymopentin combined with ceftriaxone on patients with early syphilis serum fixation.Methods A total of 108 patients with early syphilis serum fixation were chosen and divided into observation group and control group by the number of tables (54 cases in each group).The control group were underwent conventional sodium penicillin with benzathine with nursing treatment,the observation group were treated with ceftriaxone thymopentin combined with nursing treatment,changes in the relevant indicators before and after treat-ment were observed.Results After treatment,IL -2,IL -10 and other indicators in the observation group were improved compared to the control group[IL -2:the control group before treatment (20.8 ±4.9)μg/L,after treatment (42.7 ±7.3)μg/L;the observation group before treatment(19.8 ±5.1)μg/L,after treatment (54.6 ±8.3)μg/L;IL -10:the control group before treatment (76.3 ±16.1)μg/L,after treatment (51.3 ±5.4)μg/L;the observation group before treatment(78.3 ±4.1)μg/L,after treatment(23.8 ±5.1)μg/L],the differences of the two groups after treatment were statistically significant (t =3.923,8.832,all P <0.05);after treatment,the RPR negative rates of the observation group at 3,6,12 months after treatment(72.2%,85.2%,96.3%)was significantly higher than those of the control group(53.7%,57.4%,63.0%),the differences were statistically significant (χ2 =4.932,11.372, 22.842,all P <0.05);the efficacy of the observation group at 3,6,12 months after treatment(75.9%,79.6%, 75.9%)were significantly better than those of the control group (72.2%,64.8%,57.4%),the differences were statistically significant (χ2 =5.232,6.183,all P <0.05 ).Conclusion Thymopentin combined with ceftriaxone treatment of early syphilis can significantly improve its fixed immunological parameters,which coordinated with nursing measures can strengthen patient care awareness,then the efficacy will be better,so it is worthy of clinical further promotion.

OBJECTIVETo evaluate the breakthrough varicella infection rate and varicella vaccine effectiveness (VE) among children who received 1-dose varicella vaccine.

METHODSA total of 57 180 subjects for the consecutive 4-year birth cohorts were selected from the local children born between 2007 and 2010 in Yinzhou District, Ninghai County and Yuyao City. And they were followed up for varicella from 2008 to 2013. The recipients of the vaccinations were identified through Ningbo Immunization Information System and data on breakthrough infections among the recipients were collected by using China Information System for Disease Control and Prevention. The breakthrough varicella rate and the VE were calculated and the trends of them were described from 2008 to 2013 among 4-year birth cohorts. The cumulative incidence of varicella was compared between vaccinated and unvaccinated children among the consecutive 4-year birth cohorts.

RESULTSThe rate of varicella vaccine coverage, vaccine cumulative incidence among the cohorts was 96.74% (55 317/57 180) and 0.56% (321/57 180). The breakthrough varicella infection for 4-year birth cohorts was 0.44% (244/55 317), and for each birth cohort was 0.95% (142/14 928), 0.44% (61/13 855), 0.22% (29/13 433) and 0.09% (12/13 101), respectively. It was on the rise from 2008 to 2013 and the 2007 birth cohort of it increased fastest from 0.04% (6/14 928) in 2007 to 0.32% (48/14 834) in 2013. The vaccine cumulative incidence of these who vaccinated 1-dose varicella (the breakthrough varicella infection) was lower than these who were unvaccinated (the incidence: 6.25% (37/592), 3.52% (15/426), 3.69% (17/461) and 2.08% (8/384)) by each birth cohort (χ²= 130.27, P < 0.001 for 2007 birth cohort; χ²= 74.11, P < 0.001 for 2008 birth cohort; χ²= 162.80, P < 0.001 for 2009 birth cohort; χ²= 100.01, P < 0.001 for 2010 birth cohort). The vaccine effectiveness for 4-year birth cohorts was 89.33% (95% CI: 86.7%-92.1%) and for each birth corhort was 84.78% (95% CI: 77.94%-89.50%), 86.82% (95% CI: 77.82%-92.95%), 93.99% (95% CI: 89.27%-96.81%) and 95.60% (95% CI: 89.18%-98.21%), respectively. The effectiveness of each birth cohort declinedgradually from 2008 to 2013 and the 2009 birth cohort of it decreased fastest from 98.86% in 2010 to 66.83% in 2013.

CONCLUSIONSThe 1-dose varicella vaccine effectiveness was good, but breakthrough varicella infection rate was on the rise with time and the VE declined gradually from 2008 to 2013.

Chickenpox ; Chickenpox Vaccine ; Child ; China ; Humans ; Incidence ; Vaccination ; Vaccine Potency

Objective To evaluate the breakthrough varicella infection rate and varicella vaccine effectiveness(VE) among children who received 1-dose varicella vaccine. Methods A total of 57 180 subjects for the consecutive 4-year birth cohorts were selected from the local children born between 2007 and 2010 in Yinzhou District, Ninghai County and Yuyao City.And they were followed up for varicella from 2008 to 2013. The recipients of the vaccinations were identified through Ningbo Immunization Information System and data on breakthrough infections among the recipients were collected by using China Information System for Disease Control and Prevention. The breakthrough varicella rate and the VE were calculated and the trends of them were described from 2008 to 2013 among 4-year birth cohorts.The cumulative incidence of varicella was compared between vaccinated and unvaccinated children among the consecutive 4-year birth cohorts. Results The rate of varicella vaccine coverage, vaccine cumulative incidence among the cohorts was 96.74%(55 317/57 180)and 0.56%(321/57 180). The breakthrough varicella infection for 4-year birth cohorts was 0.44%(244/55 317), and for each birth cohort was 0.95%(142/14 928),0.44%(61/13 855), 0.22%(29/13 433)and 0.09%(12/13 101), respectively. It was on the rise from 2008 to 2013 and the 2007 birth cohort of it increased fastest from 0.04%(6/14 928)in 2007 to 0.32%(48/14 834)in 2013.The vaccine cumulative incidence of these who vaccinated 1-dose varicella(the breakthrough varicella infection) was lower than these who were unvaccinated(the incidence:6.25%(37/592),3.52%(15/426),3.69%(17/461) and 2.08%(8/384))by each birth cohort(χ2=130.27,P<0.001 for 2007 birth cohort;χ2=74.11,P<0.001 for 2008 birth cohort;χ2=162.80,P<0.001 for 2009 birth cohort;χ2=100.01,P<0.001 for 2010 birth cohort) .The vaccine effectiveness for 4-year birth cohorts was 89.33%(95%CI:86.7%-92.1%) and for each birth corhort was 84.78%(95%CI:77.94%-89.50%),86.82%(95%CI:77.82%-92.95%),93.99%(95%CI:89.27%-96.81%)and 95.60%(95%CI:89.18%-98.21%), respectively. The effectiveness of each birth cohort declinedgradually from 2008 to 2013 and the 2009 birth cohort of it decreased fastest from 98.86%in 2010 to 66.83% in 2013. Conclusions The 1-dose varicella vaccine effectiveness was good, but breakthrough varicella infection rate was on the rise with time and the VE declined gradually from 2008 to 2013.

Objective To evaluate the breakthrough varicella infection rate and varicella vaccine effectiveness(VE) among children who received 1-dose varicella vaccine. Methods A total of 57 180 subjects for the consecutive 4-year birth cohorts were selected from the local children born between 2007 and 2010 in Yinzhou District, Ninghai County and Yuyao City.And they were followed up for varicella from 2008 to 2013. The recipients of the vaccinations were identified through Ningbo Immunization Information System and data on breakthrough infections among the recipients were collected by using China Information System for Disease Control and Prevention. The breakthrough varicella rate and the VE were calculated and the trends of them were described from 2008 to 2013 among 4-year birth cohorts.The cumulative incidence of varicella was compared between vaccinated and unvaccinated children among the consecutive 4-year birth cohorts. Results The rate of varicella vaccine coverage, vaccine cumulative incidence among the cohorts was 96.74%(55 317/57 180)and 0.56%(321/57 180). The breakthrough varicella infection for 4-year birth cohorts was 0.44%(244/55 317), and for each birth cohort was 0.95%(142/14 928),0.44%(61/13 855), 0.22%(29/13 433)and 0.09%(12/13 101), respectively. It was on the rise from 2008 to 2013 and the 2007 birth cohort of it increased fastest from 0.04%(6/14 928)in 2007 to 0.32%(48/14 834)in 2013.The vaccine cumulative incidence of these who vaccinated 1-dose varicella(the breakthrough varicella infection) was lower than these who were unvaccinated(the incidence:6.25%(37/592),3.52%(15/426),3.69%(17/461) and 2.08%(8/384))by each birth cohort(χ2=130.27,P<0.001 for 2007 birth cohort;χ2=74.11,P<0.001 for 2008 birth cohort;χ2=162.80,P<0.001 for 2009 birth cohort;χ2=100.01,P<0.001 for 2010 birth cohort) .The vaccine effectiveness for 4-year birth cohorts was 89.33%(95%CI:86.7%-92.1%) and for each birth corhort was 84.78%(95%CI:77.94%-89.50%),86.82%(95%CI:77.82%-92.95%),93.99%(95%CI:89.27%-96.81%)and 95.60%(95%CI:89.18%-98.21%), respectively. The effectiveness of each birth cohort declinedgradually from 2008 to 2013 and the 2009 birth cohort of it decreased fastest from 98.86%in 2010 to 66.83% in 2013. Conclusions The 1-dose varicella vaccine effectiveness was good, but breakthrough varicella infection rate was on the rise with time and the VE declined gradually from 2008 to 2013.

OBJECTIVETo analyze the epidemiological characteristics and the bacterial pathogen composition of pneumonia among children under 5 years old in Ningbo.

METHODSIn 2013 February-April, we selected pediatric ward in three hospitals according to stratified cluster random sampling, and from which we collected all 57 556 hospitalized cases in January 2009-December 2012 period of children under 5 years old. A total of 16 740 medical records and bacterial spectrum records of pneumonia or bronchial pneumonia cases among children under 5 years old were described to calculate the proportions of children pneumonia or bronchial pneumonia hospitalized cases accounted for hospitalized children over the same period(referred to as proportions of pneumonia incidence), the detection rate of bacterial pathogens, proportions of bacterial spectrum, and to analyze the characteristics and bacterial pathogen composition of pneumonia among children under 5 years.

RESULTSThe proportions of children pneumonia in 2009-2012 were 26.16% (2 882/11 017), 31.23% (4 004/12 819), 29.35% (4 898/16 689) and 29.10% (4 956/17 031)(Z = 3.13, P < 0.01), and were in a downward trend by the increasing of age(Z = -113.74, P < 0.01). The proportions of children pneumonia of 0-5 age group were 50.71% (6 756/13 318), 26.60% (3 159/11 877), 24.17% (2 574 /10 648), 22.36% (2 509 /11 223) and 16.63% (1 745 /10 490). The proportions of children pneumonia with different season were 26.90% (3 725/13 850), 26.51% (3 788/14 287), 29.59% (4 442/15 011) and 33.21% (4 785 /14 408) (χ² = 198.77, P < 0.01). The proportions of severe children pneumonia of 0-5 age group were 1.10% (74/6 753), 0.47% (15/3 159), 0.19% (5 /2 574),0.08% (2 /2 509) and 0.06% (1 /1 745), with a downward trend by the age(F = 57.62, P < 0.01). The detection rate of Klebsiella pneumoniae, Haemophilus influenzae,Acinetobacter baumannii, Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae was 19.3% (540/2 805), 16.4% (460/2 805), 13.6% (381/2 805), 11.9% (335/2 805), 11.5% (323/2 805) and 6.8% (192/2 805).

CONCLUSIONIn 2009-2012, the proportions of children pneumonia under 5 year old constituted a relatively high proportion in Ningbo city. Children under 1 year old were the major suffering group of pneumonia and severe pneumonia, which should be the key prevention group. The major bacterial pathogens of children's pneumonia in Ningbo are gram-negative bacteria.

Acinetobacter baumannii ; Child ; Epidemics ; Escherichia coli ; Gram-Negative Bacteria ; Haemophilus influenzae ; Humans ; Incidence ; Infant ; Klebsiella pneumoniae ; Pneumonia ; Staphylococcus aureus ; Streptococcus pneumoniae