[Prenatal screening for major fetal heart defects by training sonographers in township hospitals and county health centers: a feasibility study].

OBJECTIVE: To explore the feasibility of screening for major fetal heart disease by training sonographers in township or county level hospitals. METHODS: Training of B ultrasound scan for congenital heart defects was given to the sonographers from one county hospital, and thirteen township hospitals (or the district hospitals), and training of fetal echocardiography was given to sonographers from four city/county hospitals. The trained sonographers who had passed the examinations and had obtained qualifications after six months of independent practice began to screen fetal congenital heart defects. To evaluate the effectiveness, sensitivity and specificity of screening was calculated by using the diagnosis of expert neonatal/fetal echocardiographers as the gold standard. RESULTS: A total of 3 425 fetuses received one fetal B ultrasound screening, one fetal echocardiography and one neonatal echocardiography from April 1, 2004 to December 31, 2005. One hundred and sixty-five B ultrasound screening images (4.9%) from township hospitals and fifty-six fetal echocardiography images (1.7%) from county or city centers couldn't be reviewed because of poor quality. The sensitivity of fetal B ultrasound screening in the township and county hospitals was 30% and 0, and the specificity 93.3% and 99.9%, respectively. Nine fetuses with a major congenital heart disease were eventually found by the trained sonographers, and two cases were misdiagnosed and two unnoticed. The total sensitivity and specificity of fetal echocardiography were 81.8% and 99.9%, respectively. The sensitivity in the county and city hospitals was 66.7% and 100%, respectively. The specificity in the county and city hospitals was 99.9% and 100%, respectively. CONCLUSION: Under the current circumstances, township hospitals are unable to perform effective fetal cardiac screening. Screening on fetal congenital heart disease is suggested to be taken by trained sonographers in county and city level medical centers.

[Analysis of adverse events following 2009 influenza A (H1N1) vaccinoprophylaxis in Beijing].

OBJECTIVE: To evaluate the safety of 2009 influenza A (H1N1) vaccine based on mass immunization initiative in Beijing. METHOD: There were 2 113 280 people were vaccinated during September to December 2009. The information of adverse events following immunization (AEFI) was collected through surveillance system, and descriptive methodology was used for data analysis. RESULTS: A Total of 612 AEFI cases were reported, among which there were 321 vaccine reaction cases following immunization, 203 coincidental illness cases, 82 psychogenic reaction cases, and 6 pending cases. The rates of rare reactions and common reactions associated with vaccination were respectively 5.54/100 000 (117/2 113 280) and 9.65/100 000 (204/2 113 280). The rate of serious rare reaction was 0.19/100 000 (4/2 113 280). The rates of vaccine reactions in urban, suburb and county were 16.87/100 000 (36/213 519), 17.81/100 000 (187/1 049 817) and 11.53/100 000 (98/849 944), respectively. The rates of rare reaction and common reaction in different age groups were between 3.65/100 000 (6/164 604) to 8.99/100 000 (27/300 176), and between 0.61/100 000 (1/164 604) to 22.06/100 000 (85/385 275). The 117 rear vaccine reaction cases were mainly allergic reaction (107 cases), and the 204 common vaccine reaction cases were mainly fever (176 cases). There were 91.90% (295/321) vaccine reactions occurred within 24 hours of administration, and all cases had improved consequence. CONCLUSION: The mostly symptoms of AEFI cases during the period of 2009 influenza A (H1N1) vaccinoprophylaxis were anaphylaxis and fever. The types of adverse reactions and the level of serious events are consistent with the anticipation. There were no rear or new events occurred.

[Study on the cellular and humoral immunity effect of recombinant Chinese hamster ovary cell hepatitis B vaccine in adults].

OBJECTIVE: To evaluate the cellular and humoral immunity effect of 10 µg and 20 µg recombinant Chinese hamster ovary (CHO) cell hepatitis B vaccine in adults by randomized double-blind controlled trials. METHOD: A total of 642 adults aged 18 - 45 years old, non-vaccinated against hepatitis B, and hepatitis B five blood indicators negative were selected as the study subjects. The study subjects were randomly divided into two groups and each group had 321 subjects. The subjects were given 10 µg and 20 µg recombinant CHO hepatitis B vaccination respectively by 0, 1st, 6th month schedule. Blood sample was collected from each study subject one month after the second dose vaccination. The anti-HBs level was detected by Abbott chemiluminescence detection method (I2000) to evaluate humoral immunity status. Of all the study objects, 153 cases were randomly selected by the Excel random function. Their blood samples were collected and Lymphocyte were separated to detect the IL-4 and IFN-γ levels in vitro by enzyme-linked immunospot (ELISPOT) method to evaluate the cellular immunity status. RESULTS: The anti-HBs seroconversion rates in 10 µg and 20 µg dose group were 88.8% (285/321) and 95.3% (306/321) respectively, and 95%CI were 85.4% - 92.2% and 93.0% - 97.6% respectively. The spot forming cell (SFC) of IL-4 of the 20 µg-dose group (x(-) = 20.31) were significantly higher than the 10 µg-dose group (x(-) = 8.19, t = 3.27, P < 0.01). With the increasing of anti-HBs titer, the SFC of IL-4 also went up significantly. There was a positive correlation between SFC of IL-4 and anti-HBs (Spearman correlation coefficient = 0.538, P < 0.0001). No significant difference was found for IFN-γ SFC in two groups (10 µg group: x(-) = 1.49; 20 µg group: x(-) = 0.86; t = 1.83, P > 0.05). CONCLUSION: The humoral and cellular immune effects of 20 µg recombinant CHO hepatitis B vaccine are better than that of the 10 µg recombinant CHO hepatitis B vaccine.20 µg recombinant CHO hepatitis B vaccine should be chosen as the adult's hepatitis B prevention vaccine.

The molecular characterization of serogroup C Neisseria meningitidis strains circulating in Beijing.

The aim of this study was to characterize the molecular features of serogroup C Neisseria meningitidis strains circulating in Beijing, China. Twenty out of 23 strains belonged to ST 4821. The causative serosubtype for meningococcal meningitis was P1.12-1,16-8. All of the strains expressed class 3 PorB protein. Among the five pulsed-field gel electrophoresis patterns observed, pattern III predominated.

Laboratory confirmation of a suspicious meningococcal meningitis death case.

A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.

Safety and immunogenicity of two freeze-dried Vero cell rabies vaccines for human use in post-exposure prophylaxis.

To provide basis for human rabies vaccination in China, the safety and immunogenicity of two freeze-dried Vero cell rabies vaccines for human use were assessed. A total of 250 volunteers were enrolled and divided into two groups: volunteers in Group A (n=200) were vaccinated five doses of Speeda Vero cell rabies vaccine manufactured by Liaoning Chengda Biotechnology Co. Ltd. on day 0, 3, 7, 14, 28 after exposure. Volunteers in Group B (n=50) were treated with Verorab Vero cell rabies vaccine manufactured by Sanofi Pasteur on the same schedule. The local and systematic adverse reactions were observed. Serum neutralizing antibody levels of 80 individuals in Group A and 50 individuals in Group B were tested with RFFIT on day 7, 14, 45, 180, 360 after the first dose. The seroconversion rates in Groups A and B were 40.3% and 37.0% on day 7 after the first dose, 95.5% and 97.7% on day 14, 100% and 100% on day 45, 100% and 100% on day 180, 89.1% and 89.5% on day 360 respectively, indicating no significant differences between the two groups. And no significant differences were found between the neutralizing antibody geometric mean titers (GMTs) of the two groups on day 7, 14, 45, 180 and 360 after the first dose, with the GMTs of day 14, 45, 180 and 360 all higher than 0.5IU/ml. Antibody levels of the two groups peaked around 2 weeks after the full vaccination program, followed by a 55% decrease up to day 180 and another 76% decrease up to day 360. Both groups experienced occasions of transient fever, rash, edema, and scleroma after vaccination. Neither group had any severe adverse reactions. It was concluded that both vaccines showed satisfactory safety and immunogenicity. Booster vaccination is recommended following another exposure after six months since the full vaccination program.

[Study on the immuno-effects and influencing factors of Chinese hamster ovary (CHO) cell hepatitis B vaccine among adults, under different dosages].

OBJECTIVE: To evaluate the immuno-effect and related influencing factors on 10 µg and 20 µg Chinese hamster ovary (CHO) cell hepatitis B vaccine, using the randomized double-blind controlled trials in adult population. METHODS: A total of 642 adults aged 18 - 45 years old, non-vaccinated against hepatitis B, and negative on five blood indicators for hepatitis B, were selected as the study objects from four districts in Beijing. The study objects were randomly divided into two groups, and then accepted 10 µg and 20 µg recombinant CHO hepatitis B vaccination by 0 - 1 - 6 month schedule. Influencing factors were investigated by means of questionnaire. Blood samples were collected one month after the third dose of vaccination. Anti-HBs level was detected by Abott chemiluminescence detection method. For the anti-HBs negative person, fluorescent quantitative PCR method was used to find out if the person had been infected with HBV. Logistic regression analysis was used to find out the influencing factors of anti-HBs seroconversion on every studied subject. RESULTS: The anti-HBs seroconversion rates on 10 µg and 20 µg dose groups were 88.8% (95%CI: 85.4% - 92.2%) and 95.3% (95%CI: 93.0% - 97.6%) respectively. Taking the anti-HBs level < 100 mIU/ml as the low/non-response standard, the low response and non-response rates were 34.3% and 17.4% respectively. The geometric mean titers (GMT) of anti-HBs were 173.42 mIU/ml for the 10 µg dose group and 588.51 mIU/ml for the 20 µg dose group. Data from the Multivariate analysis showed that:diabetes, spouses infected with hepatitis B virus and old age were unfavorable factors for anti-HBs Seroconversion. 20 µg dose of the vaccine was conducive to seroconversion. CONCLUSION: 20 µg CHO hepatitis B vaccine seemed better than 10 µg CHO hepatitis B vaccine while many factors need to be taken into account for evaluation on hepatitis B vaccines.

[Effectiveness on post-exposure vaccination of varicella and its influencing factors in elementary schools in Beijing].

OBJECTIVE: To evaluate the effectiveness of post-exposure varicella vaccination in elementary schools in Beijing and to explore its influencing factors. METHODS: From May to July 2007, varicella cases from 49 elementary schools in 4 districts in Beijing were observed prospectively. The study included 7882 children who were from the same classrooms, same floor or same bungalow areas with the varicella cases. Vaccination status, history on varicella and onset of rashes were collected to calculate the secondary attack rate among those children under observation and then the effectiveness of vaccine was calculated. RESULTS: The protection rate on post-exposure vaccination among children under observation was 85.26%. The rates were higher when the 1st case had received varicella vaccine before the onset, vaccines were administered soon after the exposure or there were less varicella cases occurred in the schools. For children in the same class, same floor or bungalow with varicella cases before post-exposure vaccination, the average rates of protection by vaccination were 84.26% and 87.06%, respectively. When the 1st case had received varicella vaccine prior to the onset, the post-exposure protection rates reached 92.09% and 93.06%, respectively, higher than that of the case when the 1st case had received no vaccination. When the administration of vaccine right after the occurrence of first varicella case, the rates of the effectiveness of vaccine were 83.09% and 93.02%, both of which were higher than that of vaccine administered after the occurrence of 2 or 3 cases. When the vaccine administration of vaccination combined with the isolation of the already infected cases or within 5 days after the onset of the 1st case, the vaccine effectiveness could reach 86.60% and 92.73%, both were higher than otherwise. However, in those schools that bungalows were used as classrooms but without bus, canteen from school or student lodgings, it seemed that post exposure vaccination was more effective in preventing varicella from occurring. CONCLUSION: Varicella vaccination after exposure in elementary schools in Beijing was effective in prevention and control of the disease. Immediate administration together with the isolation of cases could maximize the effectiveness of the vaccine.