Evaluating the real-world vaccine effectiveness using a regression discontinuity design / 中华流行病学杂志

Estimating the actual real-world effectiveness of the vaccine is an essential part of the post-marketing evaluation. This regression discontinuity design (RDD) using observational data is designed to quantify the effect of an intervention when eligibility for the intervention is based on a defined cutoff as age, making it suited to estimate vaccine effects. This approach can avoid the high cost and ethical issues; overcome difficulties in the organization and practice process in randomized controlled trials, which leads to a higher level of causal inference evidence and more realistic results. Here, we describe key features of RDD in general, and then specific scenarios, with examples, to illustrate that RDD are an essential tool for advancing our understanding of vaccine effects.

Advances in research of interchangeable immunization with live attenuated Japanese encephalitis vaccines and inactivated vaccines / 中华预防医学杂志

Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis in Asia and the Western Pacific, which mainly invades central nervous system. Vaccination is the most important strategy to prevent JE. Currently, both live attenuated Japanese encephalitis vaccines (JE-L) and inactivated vaccines (JE-I) are in use. Due to the supply of vaccines and the personal choice of recipients, there will be a demand for interchangeable immunization of these two vaccines. However, relevant research is limited. By reviewing domestic and foreign research evidence, this article summarizes the current situation of the interchangeable use of JE-L and JE-I, and makes recommendations when the interchangeable immunization is in urgent need, so as to provide reference for practical vaccination and policymaking in China.

Epidemiological characteristics and spatiotemporal clustering of hepatitis A in Zhejiang Province from 2010 to 2019 / 中华预防医学杂志

Objective: To analyze the epidemiological characteristics and spatiotemporal clustering of hepatitis A in Zhejiang Province from 2010 to 2019. Methods: The data of hepatitis A incidence in Zhejiang Province from 2010 to 2019 were collected from the infectious disease surveillance system of China Information System for Disease Control and Prevention. ArcGIS 10.7 software was used for spatial autocorrelation analysis. SaTScan 9.6 software was used for spatiotemporal scanning analysis. SPSS 25.0 software was used for additional analysis. Results: Zhejiang Province has reported 5 465 cases of hepatitis A in 2010-2019 years, with an average annual incidence rate of 1.00/100 000, and periodicity and seasonality are not obvious. The incidence of male was higher than that of female (P=0.023), and the highest incidence rate was 50-59 years old. Spatial autocorrelation analysis showed that there was a positive spatial correlation between the incidence of hepatitis A in Zhejiang Province from 2010 to 2017, with the weakest correlation in 2010 (Moran's I =0.103, Z=1.769, P=0.049), and the strongest correlation in 2016 (Moran's I=0.328, Z=4.979, P=0.001). Spatiotemporal scanning analysis showed that there was spatial aggregation of hepatitis A in Zhejiang Province from 2010 to 2019, with a total of three aggregation areas identified. Among them, the mostly aggregation area was concentrated in Xiangshan county of Ningbo city, which covered 10 counties (cities and districts), including Ninghai county and Yinzhou district, and appeared from January 1 to June 30, 2012. Conclusion: The incidence level of hepatitis A in Zhejiang Province shows a stable fluctuation trend from 2010 to 2019, and the seasonal regularity is not obvious. The population group aged 50-59 years old is the key population. There is spatial aggregation in the epidemic situation of hepatitis A. Targeted prevention and control measures of hepatitis A should be done based on the law of spatiotemporal aggregation and local incidence.

Economic evaluation on new strategy for preventing poliomyelitis in Zhejiang Province / 预防医学

Objective To evaluate the economic effect of new strategy for preventing poliomyelitis in Zhejiang Province. Methods Based on the population of Zhejiang Province in 2016, cost-effectiveness ratio (CER) , benefit-cost ratio (BCR), and net benefit (NB) were applied to calculate the health economic difference for the new strategy and the original strategy as compared to no vaccination strategy. Univariate sensitivity analysis was used to assess the robustness of results with main parameters; including burdens of poliomyelitis, cost of vaccines, and the vaccination program itself, and the discount rate. Results CERdisease, CERdeath, BCR and NB for the new strategy were 1:52700 RMB Yuan per case, 1:1813700 RMB Yuan per case, 12.26 and 796.6622 million and CERdisease, CERdeath, BCR and NB for the original strategy were 1 :32900 RMB Yuan per case, 1 :1133900 RMB Yuan per case, 19.58 and 823.1753 million, respectively. The results of the univariate sensitivity analysis with main parameters were robust. Conclusion The new strategy for preventing poliomyelitis is necessary for this period of the global polio eradication. Though the new strategy appears not as good as the original strategy on economic evaluation, its health economic benefit is significant.

An analysis on epidemiological characteristics of Japanese encephalitis in Zhejiang Province / 预防医学

Objective To analyze the epidemiological characteristics of Japanese encephalitis (JE) in Zhejiang Province from 2007 to 2016 for developing the measures of control and prevention. Methods The data were collected from national notifiable diseases registry system (NNDRS) and case-based JE surveillance system (JESS) from 2007 to 2016, and they were analyzed through descriptive epidemiological method and Microsoft Office Excel 2010. Results From 2007 to 2016, a total of 595 JE cases were reported in Zhejiang Province, with an average annual incidence of 0.114 per 100000 population, among which, 559 (93.95%) were laboratory confirmed. During the ten years, 20 cases died and the average annual case fatality rate was 3.36% . Cases were distributed mainly in Wenzhou, Ningbo and Taizhou Cities, which accounting for 54.79% of the total.The peak months were July, accounting for 86.89% of all the cases.And 85.71% of all the cases were in the age of 0-14 years and 47.73% were scattered children.And 22.77% of the JE cases were vaccinated but 14.01% of them did not complete the whole course.And 77.23% of the cases did not have the experience of vaccination or unknown.Conclusion The incidence of JE is decreasing. The occurrence of JE is sporadic with distinct seasonal peak and mainly concentrating in young-age children.

An analysis on the hepatitis B report data from a pilot surveillance in Zhejiang Province / 预防医学

Objective To evaluate the quality of the hepatitis B report data on a pilot surveillance in Zhejiang Province from 2013 to 2015.Methods Hepatitis B report data of 6 pilots in Zhejiang Province from 2013 to 2015 were extracted from national notifiable infectious disease reporting system,including reported cases of hepatitis B,classification of hepatitis B cases and supplementary card information etc. To evaluate the accuracy of hepatitis B classification,information of supplementary cards was used to make classification diagnose for hepatitis B.Results A total of 3214 hepatitis B cases were reported in 6 pilot surveillance counties in Zhejiang Province between 2013 and 2015. Excluded 32 duplicated cases within the year and between years,3182 hepatitis B cases were actually reported,hepatitis B cases repeated reporting rate was 1%. A total of 2717 hepatitis B cases were correctly classified,and the accuracy rate of classification was 85.39%,showing an increasing trend (P<0.05). The proportion of accurate classification of reported hepatitis B by referring to the results of positive time of HBsAg and ALT from the supplementary card were 80.86% and 97.29% respectively. Among those reported acute hepatitis B cases,90.43% of them filled with anti-HBc IgM positive in supplementary card. The proportion of accurate classification of reported hepatitis B by referring to the information for liver puncture and the HBsAg and anti-HBs transform during the recovery period in supplementary cards were 0.19% and 5.13% respectively. Among those reported acute hepatitis B cases,0.69% of them were chronic or undetermined. Among those reported chronic hepatitis B cases,13.92% of them were acute,undetermined or HPV carrier. Five out of 3182 cases were unclassified,accounting for 0.16%.Conclusion The quality of classification diagnosis for hepatitis B should be improved in Zhejiang Province. Filling in the supplementary card is very beneficial for the classification of hepatitis B.

A study on the status and equity of resource allocation for community vaccination services in Zhejiang Province / 预防医学

Objective To evaluate the status and equity of resource allocation for community vaccination services in Zhejiang Province.Methods A descriptive analysis was conducted,and Gini coefficient and Theil index were used to analyze the reasonableness and the demographic equity of resource allocation for community vaccination services in Zhejiang Province in 2013.Results The Gini coefficient of vaccination clinic and clinic staff based on population distribution in Zhejiang Province were 0.403 6 and 0.355 4,respectively.The total Theil index of vaccination clinic and clinic staff were 0.204 4 and 0.207 1,respectively.Both vaccination clinic and clinic staff,Theil index within the region were far higher than inter -regional Theil index.Conclusion The demographic equity of resource allocation for community vaccination services in Zhejiang Province should be improved.The disparity within the region is the main reason of unequal in resource allocation for community vaccination service.

Analysis on coverage rate of primary immunization of measles vaccine among migrant children in Yiwu, Zhejiang province from 2007 to 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the coverage rate of primary immunization of measles containing vaccine (MCV1) among migrant children in Yiwu,Zhejiang province.</p><p><b>METHODS</b>Household cluster sampling survey and probability proportion to size sampling method were adopted. A total of 967 migrant children born from 1st July 2007 to 1st July 2010 and their caregivers were selected as target population. Standard face-to-face interviews were conducted to investigate the subjects' knowledge, attitude, practice (KAP) of immunization, MCV1 vaccination and determinants. Multi-variable weighted average score method was adopted to evaluate the result of our survey on KAP. Kaplan-Meier analysis was adopted to assess the coverage of MCV1 and Cox regression analysis was adopted to explore the influencing factors associated with the coverage of MCV1.</p><p><b>RESULTS</b>Out of the 967 children, 104 were born in 2007, accounting for 10.8%; 301 were born in 2008, accounting for 31.1%; 343 were born in 2009, accounting for 35.5% and 219 were born in 2010, accounting for 22.6%. Among the surveyed caregivers, 71.9% (695/967) were mothers and 90.2% (872/976) were migrant from other provinces. According to the result of survey on KAP among caregivers, 56.2% (543/967) scored ≥ 4 points on knowledge, 75.8% (734/967) scored ≥ 4 points on attitude and 48.7% (471/967) scored ≥ 4 points on behavior. 86.6% (838/967) of surveyed caregivers' education levels were under junior middle school.85.9% (831/967) of the migrant children were born in hospitals.36.3% (351/967) of the surveyed families' household income were under 2000 yuan per month.32.7% (316/967) of surveyed caregivers waited less than 15 min for immunization for each time. Coverage rate of MCV1 was 85.9% (831/967; 95%CI: 83.7%-88.1%). The timely coverage rates at 8 months, 12 months, and 24 months were 58.8% (569/967; 95%CI: 55.5%-62.1%), 88.2% (853/967; 95%CI: 86.0%-90.4%) and 98.6% (953/967; 95%CI: 97.8%-99.4%), respectively. The average age of MCV1 immunization for each birth cohort between 2007 and 2010 were 10.4, 10.1, 10.1 and 9.3 month, respectively; without statistical significance (χ(2) = 0.722, P = 0.398). According to the analysis by Cox regression, the caregivers aged ≤ 25 years (24.3% (235/967), RR = 1.520 (95%CI: 1.280-1.800)), the caregivers' education level above college (2.8% (27/967), RR = 3.841 (95%CI: 2.287-6.451)), delivered in county-level hospital (49.4% (478/967), RR = 6.048 (95%CI: 4.311-8.485)), household income > 4000 yuan per month (21.7% (210/967), RR = 1.366 (95%CI:1.163-1.604)), the average score of attitude towards immunization ≥ 4 points (75.9%(734/967), RR = 2.613 (95%CI: 1.026-6.655)), the average waiting time for each vaccination ≤ 15 min (32.7% (316/967), RR = 2.116 (95%CI: 1.341-3.339)) were the important factors to improve the timely immunization coverage rate of MCV1 among migrant children.</p><p><b>CONCLUSION</b>The coverage of MCV1 were obviously delayed among migrant children in Yiwu, Zhejiang province. We suggest that the investigation of migrant children should be strengthened and remind or recall mechanism for immunization should be established. Increasing the open days for immunization clinics and reducing the waiting time for vaccination could also improve the coverage and timeliness of the MCV vaccination.</p>

Study on the molecular characteristics of Japanese encephalitis virus living in vector mosquitoes, in Zhejiang province, 2009-2010 / 中华流行病学杂志

Objective To investigate the molecular characteristics of Japanese encephalitis virus (JEV) living in vector mosquitoes,from Zhejiang province.Methods A total of 13620 mosquitoes were collected from the monitoring stations located in Cixi city and Xianju county in Zhejiang province,in July and August,2009-2010.Nucleic acid of JEV from the mosquitoes was monitored by using real-time RT-PCR.The virus strains were isolated with BHK-21 cell line,with E genes of the isolated viruses amplified,sequenced and their phylogeny and homology analyzed.Results The positive rates of JEV for those mosquitoes collected in the stations of Cixi and Xianju were 17.0％ (27/159) and 3.4％ ( 1/29 ),respectively.Twenty-two JEV strains were isolated,accounted for 15.4％ among the 143 batches of mosquitoes collected in 2010.All E genes in the 6 sequenced virus isolates contained 1500 nucleotides encoding 500 amino acids,in which no inserts and deletions were identified.The identity rates of nucleotide and amino acid in E gene were 99.2％-99.8％ and 100.0％ among the 6 JEV strains isolated from Zhejiang,99.1％-99.3％ and 99.2％-99.8％ between the Zhejiang strains in 2009-2010 and the Zhejiang strains in 2007-2008,respectively,87.6％-88.0％ and 97.8％ between the 6 Zhejiang strains and the vaccine strain SA 14-14-2 of JEV,respectively.The phylogeny tree of E gene indicated that the JEV isolates in Zhejiang during 2009-2010 was located in the branch of the genotype Ⅰ.Conclusion Mosquitoes collected from Cixi and Xianju areas carried JEV,with the rate of JEV in Cixi higher than in Xianju.All the Zhejiang isolates in 2009-2010 were proven to be the genotype Ⅰ of JEV.