Cross immunity study of two different influenza A3 virus vaccine strain / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the cross immunity response between two similar strains of influenza A3 virus vaccine from 2007 to 2008.</p><p><b>METHODS</b>Healthy adults aged 18-60 years old without history of flu vaccination were inoculated Anflu ™( 52 cases) or VAXIGRIP ® (137 cases) influenza split vaccine. A micro-hemagglutination inhibition (HI) assay was used to test the serum specimens collected from the subjects before and after vaccination. The seroconversion rate, geometric mean titer (GMT) and antibody protective rate were used to evaluate the effect.</p><p><b>RESULTS</b>The seroconversion rates of Anflu ™ and VAXIGRIP ® tested by A/Hiroshima/52/2005 virus antigen were 82.7% (95%CI: 69.2% - 91.8%) and 80.3% (95%CI: 72.4% - 86.5%) respectively and there was no significant difference (χ(2) = 0.141, P > 0.05). The seroconversion rates of Anflu™ and VAXIGRIP ® tested by A/Wisconsin/67/2005 (H3N2)-like virus antigen were 71.2% (95%CI: 56.7% - 82.8%) and 73.7% (95%CI: 65.4% - 80.8%) respectively and there was no significant difference observed (χ(2) = 0.126, P > 0.05). GMT of Anflu™ and VAXIGRIP ® tested by A/Hiroshima/52/2005 virus antigen after vaccination increased 11.5 (95%CI: 7.5 - 17.5) times and 13.0 (95%CI: 10.0 - 16.9) times without significant difference (F = 0.497, P > 0.05). GMT of Anflu ™ and VAXIGRIP ® tested by A/Wisconsin/67/2005 (H3N2)-like virus antigen after vaccination increased 9.5 (95%CI: 6.3 - 14.3) and 10.9 (95%CI: 8.5 - 13.7) times, and there was no significant difference either (F = 0.554, P > 0.05). The antibody protective rate of two vaccines before and after immunity tested by A/Hiroshima/52/2005 virus antigen were 48.1% and 54.7% before vaccination and 98.1% and 95.6%after vaccination respectively without significant difference (χ(2) = 0.135 - 0.673, P > 0.05). The antibody protective rates of two vaccines tested by A/Wisconsin/67/2005 (H3N2)-like virus antigen were 11.5% and 13.9%before vaccination and 80.8% and 86.1%after vaccination respectively, and there was no significant difference (χ(2) = 0.178 - 0.834, P > 0.05). But the results tested by A/Hiroshima/52/2005 virus antigen were higher than those of A/Wisconsin/67/2005 (H3N2)-like virus antigen (χ(2) = 7.111 - 52.155, P < 0.01).</p><p><b>CONCLUSION</b>The two similar seasonal influenza vaccine strains recommended by WHO had a good cross immunity response, but the systematic error of test existed in two similar stains and the same strains should be used.</p>

Safety and immunogenicity on three lots of influenza split vaccines among adults / 中华流行病学杂志

Objective To evaluate the irnmunogenicity, safety and stability of the manufacture process regarding three consecutive lots of influenza split vaccines (Anflu ). Methods A double-blind, randomized and controlled clinical trial was conducted in healthy volunteers. A total of 566 subjects aged 18 to 60 years were recruited and stratified into four age groups before randomly assigned into four groups. Each group would receive one dose of influenza vaccine from either one of the three lots ofAnflu or one lot of the licensed control vaccine. Each dose of the vaccines contained 15 μg of each of the H1N1, H3N2 and B type antigen. Safety was assessed through 30-minute observation for immediate allergic reaction and three-day observation after vaccination. HI antibody titers were determined before vaccination and on day 21, after vaccination. Results Mild adverse reaction was reported and the overall incidence rates on fever of the four groups were from 1.4% to 2.8% but no significant difference was observed between groups. Seroconversion rates of the three viral strains in four groups were 80.3% and above with fold increase as≥11.1 and protection rate was≥93.4%. For the three lots of investigated vaccines, all of the indexes of the three viral strains in four groups exceeded the standards on EMEA and FDA for influenza vaccine. Conclusion The three consecutive lots of Anflu appeared to be good, with both consistent immunogenieity and safety, indicating the stability of manufacture process.

Evaluation on the role of hepatitis A vaccine in the prevention and control of hepatitis A in Tianjin city / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of prevention and control strategies on hepatitis A.</p><p><b>METHODS</b>Surveillance data on hepatitis A from 1990 to 2006 in Tianjin was analyzed, and the coverage rate of hepatitis A vaccine among targeted population was estimated, to compare the anti-HAV IgG level of children younger than 15 years old in 1999 and in 2005.</p><p><b>RESULTS</b>Results showed that a) the morbidity of hepatitis A decreased from 25.26/10(5) in 1990 to 0.82/10(5) in 2006; b) the ratio of hepatitis A in viral hepatitis decreased from 30.43% in 1990 to 1.05% in 2006; c) the estimated coverage rate was 72.7%; d) the positive rate of anti-HAV among children younger than 15 years old in 2005 was distinctly higher than that in 1999.</p><p><b>CONCLUSION</b>Positive results showed that it was successful to use hepatitis A vaccine as the strategy to prevent and control hepatitis A in the past five years in Tianjin.</p>

Epidemiological characteristics of severe acute respiratory syndrome in Tianjin and the assessment of effectiveness on measures of control / 中华流行病学杂志

<p><b>OBJECTIVE</b>To analyze the epidemiologic characteristics of severe acute respiratory syndrome (SARS) and to evaluate the effectiveness on its major control measures in Tianjn.</p><p><b>METHODS</b>Adopting two case reports 1 and 2, designed by the Tianjin Centers for Disease Control and Prevention to develop a unified case-tracing table including the map of the distribution of close contacts to SARS patients. With those methods, investigation on patients and their close contacts at hospital wards, families, communities and institutions of the patients were carried out.</p><p><b>RESULTS</b>From April 13 through May 8, 2003, there were 175 SARS cases including imported ones, were identified with an incidence rate of 1.9 cases per 100,000. Among them, 14 died with a fatality of 8.0%. The whole process of epidemic in Tianjin was less than one month with the following features: (1) 93.7% of the total SARS cases in Tianjin were directly or indirectly transmitted by a super-spreader. (2) 68.6% of the total SARS patients were concentrated in 3 hospitals A, B and C which was menifastated in 'clustering'. Through study on the rest of the SARS patients, results showed that 16.8% of them were transmitted through family close contact and 2.3% due to contact to colleagues. However, 12.6% of the patients were not able to show evidence that they had any contact to a diagnosed SARS patient. At the early stage of the epidemic, a number of medical practitioners were infected, taking up 38.2% of the total SARS cases. Among the total number of 1 975 medical workers who participated in the SARS medical cares and treatments, 3.4% of them got infected. During the outbreak, all index cases and chains of transmission seemed to be clear, with only 3 patients not able to be traced for the source of infection, taking up 2% of the total SARS patients in Tianjin. Among the 10 index cases, only the super spreader and another one index case transmitted the virus to their contacts but the rest of index cases did not cause any secondary infection.</p><p><b>CONCLUSION</b>Though SARS is clinically severe and can be spreaded quickly, the epidemic can be under control within a short period of time if chains of SARS transmission are broken down and effective measures as isolation and quarantine against patients as well as underscoring awareness among the publics in a scientific way, being carried out.</p>