Seroprevalence of neutralizing antibody among SARS-CoV-2 infected individuals / 预防医学

Objective@#To investigate the seroprevalence and influencing factors of serum neutralizing antibodies among SARS-CoV-2 infected individuals, so as to provide the evidence for developing the health management and COVID-19 vaccination strategy among SARS-CoV-2 infected individuals.@*Methods@#Recovered SARS-CoV-2 infected individuals from January 1st, 2020 to February 10th, 2021 in Zhejiang Province were recruited in March 2021. Participants' demographics, underlying diseases, date of definitive diagnosis and severity of clinical symptoms were collected using questionnaire surveys, and serum neutralizing antibody against SARS-CoV-2 was detected using a fluorescent immunoassay. In addition, factors affecting the seropositivity of neutralizing antibody against SARS-CoV-2 were identified using a multivariable logistic regression model. @*Results@#A total of 559 SARS-CoV-2 infected individuals were enrolled, including 480 confirmed cases and 79 asymptomatic carriers, with an median (interquartile range) age of 47.00 (22.00) years, and all participants had never received COVID-19 vaccination. The median (interquartile range) duration from diagnosis to serum sampling was 387.00 (11.00) days, and the seroprevalence of neutralizing antibody against SARS-CoV-2 was 83.90%. The serum neutralizing antibody against SARS-CoV-2 was all positive 9 months after diagnosis, and the seroprevalence of neutralizing antibody against SARS-CoV-2 appeared no tendency towards a decline with time within 14 months after diagnosis (P>0.05). Multivariable logistic regression analysis showed that women were 1.892 times (95%CI: 1.169-3.064) more likely to produce serum neutralizing antibodies against SARS-CoV-2 than men, and mild, common and severe/critically ill SARS-CoV-2 infected cases were 2.438 (95%CI: 1.305-4.557), 4.481 (95%CI: 2.318-8.663), and 23.525 (95%CI: 2.990-185.068) times more likely to produce serum neutralizing antibodies against SARS-CoV-2 than asymptomatic carrier, respectively.@*Conclusions@#The seroprevalence of neutralizing antibody was 100.00% among SARS-CoV-2 infected individuals within 9 months after diagnosis. Individuals' gender and severity of clinical symptoms correlate with the seroprevalence of neutralizing antibody against SARS-CoV-2.

Influenza-associated excess mortality in Zhejiang Province from 2016 to 2019 / 预防医学

Objective@#To estimate the influenza-associated excess mortality (IEM) in Zhejiang Province from 2016 to 2019, so as to provide insights into estimates of mortality burden due to influenza. @* Methods@#The data pertaining to all-cause death and influenza surveillance in Zhejiang Province from 2016 to 2019 were retrieved from Zhejiang Provincial Cause of Death Registration System and Influenza Surveillance System to create distributed lag non-linear models (DLNMs). The year-, influenza subtype- and age-specific IEM rates were estimated.@*Results@#The overall IEM was 18.67/105 (95%CI: 15.32/105-21.97/105) in Zhejiang Province from 2016 to 2019, with the lowest in 2016 (14.19/105, 95%CI: 12.00/105-16.37/105) and the highest in 2018 (22.92/105, 95%CI: 19.23/105-26.56/105). The IEM rates of influenza A (H1N1), influenza A (H3N2) and influenza B were 9.32/105 (95%CI: 7.65/105-10.98/105), 5.68/105 (95%CI: 4.24/105-7.11/105), and 3.66/105 (95%CI: 2.13/105-5.18/105). The greatest IEM was seen among residents at ages of 65 years and older (142.91/105, 95%CI: (115.99/105-169.55/105, followed by among individuals at ages of 15 to 64 years (2.74/105, 95%CI: 1.87/105-3.61/105), and the lowest was seen among individuals under 15 years of age (0.41/105, 95%CI: -0.33/105-1.14/105). @*Conclusions@#From 2016 to 2019, the highest IEM was seen in Zhejiang Province in 2018, and the elderly residents at ages of 65 years and above presented the greatest IEM, with influenza A (H1N1) as the predominant influenza subtype. Influenza surveillance and vaccination is recommended to be reinforced.

Epidemiological investigation of the first reported case of coronavirus disease 2019（COVID-19）in Zhejiang Province / 预防医学

Objective@# To conduct an epidemiological investigation on the first reported case of coronavirus disease 2019 （COVID-19） in Zhejiang Province, so as to provide reference for prevention and control of the disease.@*Methods @#According to the COVID-19 Diagnosis and Treatment Program （Trial） and the COVID-19 Prevention and Control Program （Trial） issued by National Health Commission of China, a field investigation was employed on a case of fever from Wuhan reported by Wenzhou in January 15, 2020; the real-time reverse transcription polymerase chain reaction （RT-PCR） assay was performed to detect the nucleic acid of severe acute respiratory syndrome coronavirus 2 （SARS-CoV-2） from the sputum specimens or throat swabs of the case; the close contacts of the case were tracked down; relevant prevention and control measures were implemented. @*Results @#The case had lived in Wuhan for long. On January 4 of 2020, he felt cold and uncomfortable without obvious inducement, and drove back to Wenzhou with his wife. He had fever （up to 39 ℃）, cough and expectoration on the next day. On January 9, the chest computed tomographic （CT） scan showed bilateral high-density patchy shadowing with blurred edges. On January 16, his throat swab and sputum samples were collected and sent to Zhejiang Provincial Center for Disease Control and Prevention （CDC） for detection of SARS-CoV-2. The result turned out to be positive on January 17, then was rechecked and confirmed by Chinese CDC on January 20. Two weeks before the onset of the disease, the patient was engaged in the door-to-door persuasion of installing elevators in an old residential area of Wuhan, and he denied any connection with other COVID-19 cases,markets,（sick or dead） poultry or poultry products. Totally 26 close contacts were identified and kept in quarantine. During this period,three of them developed fever or respiratory symptoms, but were excluded from COVID-19. On the afternoon of January 16,the health system of Zhejiang Province and Wenzhou City launched an emergency plan and implemented a series of prevention and control measures such as isolation and treatment of cases,screening and isolation of close contacts,and public health education. @*Conclusion @#According to the epidemiological history,clinical features and laboratory test Results,the patient was identified as the first reported case of COVID-19 in Zhejiang Province.

Preliminary investigation on the influencing factors and health impacts of hookworm infection in South Mountain area of Zhejiang Province / 中华地方病学杂志

Objective To understand the demographic characteristics and clinical features of hookworm infectors in high infection area in South Mountain area of Zhejiang Province,and to find the risk factors of infection,so as to provide the evidence for formulating prevention and control measures.Methods In 2018,according to the soil-borne nematode monitoring results of the previous year in Zhejiang Province,three villages with relatively more hookworm infections were selected from Qingtian County in South Mountain area of Zhejiang Province,and more than 10 cases of hookworm infection were selected from each survey site.A face to face questionnaire survey was conducted by all investigators using a questionnaire designed by the Center for Infectious Disease Control and Prevention,Zhejiang Provincial Center for Disease Control and Prevention,and information on the general condition,past diagnosis history,clinical symptoms and risk factors of infection of infected persons were collected.The stool samples were collected and tested for infection by modified Kato-Katz method to evaluate the drug deworming effect in the previous year.Results A total of 33 cases of hookworm infection were investigated,including 18 males and 15 females;the age ranged from 33-85 years old,mainly concentrated in 60-79 years old,a total of 23 cases (69.7％).Ten cases (30.3％) had been diagnosed with hookworm disease;19 cases (57.6％) had similar symptoms of hooky dermatitis;and 12 cases (36.4％) had gastrointestinal symptoms in the past three years.There were 31 cases (93.9％) worked in the field for more than one month each year,18 cases (54.5％) used fresh manure directly at home,6 cases (18.2％) were used to working barefoot in the field,and 30 cases (90.9％) used to wearing slippers in the field.A total of 32 eligible stool samples were examined,and 4 case (12.5％) were still positive for hookworm eggs.Conclusions Among the infectors,fertilizing with fresh stool,working barefoot or wearing slippers in the field may serve as the risk factors.There is a certain failure proportion to eliminate the infection status when adopting only one round anthelminthic treatment.For prevention and control hookworm infections,comprehensive intervention measures including infection source management,harmless treatment of stools,individual behavior intervention and environment improvement are suggested.

Economic evaluation of different chickenpox vaccination strategies / 浙江大学学报·医学版

OBJECTIVE@#To evaluate the cost/benefit of different vaccination strategies related to chickenpox vaccine.@*METHODS@#The direct economic cost and indirect economic cost caused by chickenpox were obtained through questionnaire survey. The epidemic characteristics of chickenpox in Zhejiang province were studied by literature review. Dynamic model was set up by Matlab software based on the parameters of chickenpox, to predict the incidence trends of chickenpox with different immunization strategies (no vaccination, 1-dose vaccination, 2-dose vaccination) in future 40 years (2017-2056). A cost-benefit analysis was conducted, and the sensitivities of the main parameters were analyzed.@*RESULTS@#Through the questionnaire survey of 105 cases, the direct and indirect economic cost per case was 506.84 Yuan and 1045.39 Yuan respectively, with the total of 1552.23 Yuan. During the prediction period (40 years), there would be 7.0908 million cases in strategy 2, which was 59.71% less than strategy 1 (17.5989 million cases). Total vaccination costs in strategy 2 were 2.366 billion Yuan, with a total economic gain of 33.741 billion Yuan and benefit/cost ratio (BCR) of 14.26:1. If strategy 3 was adopted, 2.7249 million chickenpox cases would occur, with a decrease of 84.52% compared with strategy 1. Total vaccination costs in strategy 3 was 4.495 billion Yuan, with a total economic gain of 44.309 billion Yuan and BCR of 9.86:1. Analysis showed that the vaccine price was the most sensitive variable, followed by the incidence of chickenpox in the absence of vaccine.@*CONCLUSIONS@#In Zhejiang province, one-dose strategy and two-dose strategy were both cost effective. It is suggested that the chickenpox vaccination should be included in the immunization program in Zhejiang province.

Study on the genotypic characteristics of Japanese encephalitis virus and serology in the healthy population of Zhejiang province, 2012-2013 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To understand the genotypic characteristics and the neutralizing antibody levels of Japanese encephalitis virus (JEV) and Japanese encephalitis (JE) in both vector mosquitoes and in healthy people of Zhejiang province.</p><p><b>METHODS</b>Virus was isolated from mosquitos sampled from the Monitoring Stations located in Xianju county during 2012 to 2013. Phylogenetic and homological studies were carried out on the E gene. A total of 1 263 blood specimens from 642 healthy people were collected before and after the seasons of JE epidemics. JEV neutralizing antibody was detected by the micro-neutralization test.</p><p><b>RESULTS</b>Twenty-five JEV strains were isolated from a total of 11 650 mosquitoes. The identity of nucleotide appeared as 87.8%-99.7% both from 2012 to 2013 and from 1982 to 2010 while as 87.7%-88.0% with vaccine strain SA14-14-2, in Zhejiang. The phylogeny tree of E gene indicated that the newly isolated virus belonged to genotype I but no mutation of amino acid sequence coding conformational epitope was identified in the envelop protein. Both positive rates and the geometric mean titer (GMT) of neutralizing antibody in healthy people were 31.5%-42.0% and 1 : 2.56-1 : 3.53 in Xianju county, during 2012 and 2013, respectively. Both of the two positive rates (χ(2)≤1.76, P > 0.05) and the two GMTs (u≤0.64, P > 0.5) for antibodies pre or post the epidemic season did not show significant differences.</p><p><b>CONCLUSION</b>JEV isolated in Xianju during 2012 and 2013 belonged to genotype I. The positive rates of JEV neutralizing antibody from healthy people in Xianju were less than 42.0%, which showed no significant differendes pre or post JE epidemic season.</p>

Study on the genotypic characteristics of Japanese encephalitis virus and serology in the healthy population of Zhejiang province,2012-2013 / 中华流行病学杂志

Objective To understand the genotypic characteristics and the neutralizing antibody levels of Japanese encephalitis virus(JEV)and Japanese encephalitis(JE)in both vector mosquitoes and in healthy people of Zhejiang province. Methods Virus was isolated from mosquitos sampled from the Monitoring Stations located in Xianju county during 2012 to 2013. Phylogenetic and homological studies were carried out on the E gene. A total of 1 263 blood specimens from 642 healthy people were collected before and after the seasons of JE epidemics. JEV neutralizing antibody was detected by the micro-neutralization test. Results Twenty-five JEV strains were isolated from a total of 11 650 mosquitoes. The identity of nucleotide appeared as 87.8%-99.7% both from 2012 to 2013 and from 1982 to 2010 while as 87.7%-88.0%with vaccine strain SA14-14-2,in Zhejiang. The phylogeny tree of E gene indicated that the newly isolated virus belonged to genotypeⅠ but no mutation of amino acid sequence coding conformational epitope was identified in the envelop protein. Both positive rates and the geometric mean titer(GMT)of neutralizing antibody in healthy people were 31.5%-42.0%and 1∶2.56-1∶3.53 in Xianju county,during 2012 and 2013,respectively. Both of the two positive rates(χ2≤1.76,P>0.05)and the two GMTs(u≤0.64,P>0.5)for antibodies pre or post the epidemic season did not show significant differences. Conclusion JEV isolated in Xianju during 2012 and 2013 belonged to genotypeⅠ. The positive rates of JEV neutralizing antibody from healthy people in Xianju were less than 42.0%,which showed no significant differendes pre or post JE epidemic season.

Study on the genotypic characteristics of Japanese encephalitis virus and serology in the healthy population of Zhejiang province,2012-2013 / 中华流行病学杂志

Objective To understand the genotypic characteristics and the neutralizing antibody levels of Japanese encephalitis virus(JEV)and Japanese encephalitis(JE)in both vector mosquitoes and in healthy people of Zhejiang province. Methods Virus was isolated from mosquitos sampled from the Monitoring Stations located in Xianju county during 2012 to 2013. Phylogenetic and homological studies were carried out on the E gene. A total of 1 263 blood specimens from 642 healthy people were collected before and after the seasons of JE epidemics. JEV neutralizing antibody was detected by the micro-neutralization test. Results Twenty-five JEV strains were isolated from a total of 11 650 mosquitoes. The identity of nucleotide appeared as 87.8%-99.7% both from 2012 to 2013 and from 1982 to 2010 while as 87.7%-88.0%with vaccine strain SA14-14-2,in Zhejiang. The phylogeny tree of E gene indicated that the newly isolated virus belonged to genotypeⅠ but no mutation of amino acid sequence coding conformational epitope was identified in the envelop protein. Both positive rates and the geometric mean titer(GMT)of neutralizing antibody in healthy people were 31.5%-42.0%and 1∶2.56-1∶3.53 in Xianju county,during 2012 and 2013,respectively. Both of the two positive rates(χ2≤1.76,P>0.05)and the two GMTs(u≤0.64,P>0.5)for antibodies pre or post the epidemic season did not show significant differences. Conclusion JEV isolated in Xianju during 2012 and 2013 belonged to genotypeⅠ. The positive rates of JEV neutralizing antibody from healthy people in Xianju were less than 42.0%,which showed no significant differendes pre or post JE epidemic season.