Modeling the Long-term Antibody Response and Duration of Immune Protection Induced by an Inactivated, Preservative-free Hepatitis A Vaccine (Healive) in Children / 生物医学与环境科学（英文）

Objective@#Long-term seroprotection the hepatitis A vaccine is essential for the prevention of disease from the hepatitis A virus (HAV). Due to documented difficulties during decade-long follow-ups after receiving vaccines, statistical-modeling approaches have been applied to predict the duration of immune protection.@*Methods@#Based on five-year follow-up data from a randomized positive-controlled trial among Chinese children (1-8 years old) following a 0, 6 months vaccination schedule, a power-law model accounting for the kinetics of B-cell turnover, as well as a modified power-law model considering a memory-B-cell subpopulation, were fitted to predict the long-term immune responses induced by HAV vaccination (Healive or Havrix). Anti-HAV levels of each individual and seroconversion rates up to 30 years after vaccination were predicted.@*Results@#A total of 375 participants who completed the two-dose vaccination were included in the analysis. Both models predicted that, over a life-long period, participants vaccinated with Healive would have close but slightly higher antibody titers than those of participants vaccinated with Havrix. Additionally, consistent with previous studies, more than 90% of participants were predicted to maintain seroconversion for at least 30 years. Moreover, the modified power-law model predicted that the antibody titers would reach a plateau level after nearly 15 years post-vaccination.@*Conclusions@#Based on the results of our modeling, Healive may adequately induce long-term immune responses following a 0, 6 months vaccination schedule in children induction of memory B cells to provide stable and durable immune protection.

Safety and immunogenicity on the formulation of trivalent split influenza vaccine among healthy people aged over 18 years / 中华流行病学杂志

Objective To evaluate the safety and immunogenicity of split influenza vaccine (Anflu(R) ). Methods An open-labeled clinical trial was carried out in adults aged 18-60 years and elders aged over 60 years from August to September, 2010 in Shenyang, Liaoning province. One dose of split influenza vaccine was administered and adverse events were observed. Serum samples were obtained prior to vaccination and 21 days post vaccination. A/H1N1, A/H3N2 and B antibodies against influenza virus were measured using micro-hemagglutination inhibition (HI) assay. Results A total of 130 subjects were recruited and 120 paired serum samples were obtained. The overall rate of adverse events was 2.3% (3/130) and all of them with systemic reaction. No single serious adverse event was reported. 21 days after the vaccination, the sero-conversion rates of A/H1N1, A/H3N2 and B antibodies against influenza virus among adults were 82.5%, 93.7% and 92.1%, respectively. The Geometric Mean Titer (GMT) ratios were 20.2, 32.0 and 11.4, while the sero-protection rates were 92.1%, 98.4% and 98.4%, respectively. The sero-conversion rates of antibodies among elders were 89.5%, 91.2% and 87.7%, with the GMT ratios as 23.9, 39.8 and 15.1, respectively. The seroprotection rates were 93.0%, 94.7% and 96.5%,respectively. Conclusion All indexes ofA/H1N1,A/H3N2 and B antibodies exceeded the licensure criteria established by the EU Committee for Medicinal Products for Human Use,proving the trial vaccine Anflu(R) with good safety and immunogenicity.

Safety and immunogenicity of combined hepatitis A and hepatitis B vaccine according to 0 and 6 months schedule in healthy children / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the safety and immunogenicity of the Bilive(TM) combined hepatitis A and hepatitis B vaccine in healthy children.</p><p><b>METHODS</b>A total of 116 healthy children aged 1 - 10 years, who, without history of hepatitis A vaccine vaccination and anti-HAV negative, had completed the full immunization of hepatitis B vaccine were recruited in city of Changzhou in Jiangsu province. The Bilive(TM) combined hepatitis A and hepatitis B vaccine was administered according to a two-dose schedule (0, 6 months). The dosage was 250 U for hepatitis A antigen and 5 microg for hepatitis B surface antigen. The potential adverse effects were observed within 72 hours after vaccination. The serum samples were collected for the testing of anti-HAV and anti-HBs at month 1, 6 and 7 after initial dose.</p><p><b>RESULTS</b>The local and systemic adverse reactions after immunization were slight and temporary. The rates of local and systemic adverse reactions were 12.1% (14/116) and 6.0% (7/116). The sero-conversion rates of HAV were from 92.9% (92/99) to 100.0% (101/101) and the geometric mean titers (GMT) ranged from 47.0 mIU/ml to 2762.3 mIU/ml 1, 6, 7 months after initial dose. The sero-protection rate of HBV was 86.1% (87/101) before vaccination and came up to 100.0% (101/101) one month after initial dose, and the GMTs of HBV were from 894.3 mIU/ml to 3314.3 mIU/ml 1, 6, 7 months after initial dose.</p><p><b>CONCLUSION</b>The Bilive(TM) combined hepatitis A and hepatitis B vaccine has good safety and immunogenicity in healthy children who had preexisting immunity to hepatitis B virus.</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.

Immunogenicity and safety of three consecutive lots on a inactivated hepatitis A vaccine: a double-blind,randomized and controlled trial in children / 中华流行病学杂志

Objective To evaluate the immunogenicity, safety, stability and consistency of three consecutive lots of a inactivated hepatitis A vaccine (Healive(R)). Methods A double-blind, randomized and controlled clinical trial was conducted in healthy volunteers aged from 1 to 8 years. Totally, 400 subjects were enrolled and assigned into four groups, each receiving one of the three lots of Healive(R) or an licensed control vaccine in 0 and 6th month. Safety was assessed through a 30 minutes and three days observation,thereafter. Anti-HAV titers were determined on the 1st, 6th and 7th month after the vaccination.Results Seroconversion rate of four groups were all 100% by the end of the schedule while GMTs of Healive(R) were 3237.06-3814.14 mIU/ml but were not significantly different. GMT of control vaccine was 1467.49 mIU/ml. Healive(R) and control vaccine were well tolerated with 1%-5% incidence of overall adverse reactions in which most of them were mild and moderate. No severe adverse reaction was reported.Conclusion The three consecutive lots of Healive(R) were well consistent as indicated by immunogenicity and safety while immunogenicity was better than the vaccine used as control.

Serological investigation on close contacts to patients with severe acute respiratory syndrome in an SARS outbreak / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the evidence of severe acute respiratory syndrome (SARS) infection among close contacts to SARS patients and the level of sera IgG antibody in SARS cases.</p><p><b>METHODS</b>Specific IgG antibody against SARS-CoV in serum samples from contacts to patients, five months before an SARS outbreak in Beijing. Neutralized test, ELISA and immunity adherence test were studied. Samples were collected after clinical onset of patients or close contacts to patients, for 22 - 24 weeks. 19 close contacts and 13 cases were included in the study.</p><p><b>RESULTS</b>In close contacts, all tests were negative on three methods. All SARS cases were positive except one by immunity adherence test. The neutralized antibody levels were from 1:16 to 1:203, with medium level of 1:43.</p><p><b>CONCLUSION</b>According to our survey, there was no latent infection among close contacts. IgG antibody in sera continued to be at higher levels among SARS cases 22 - 24 weeks after onset.</p>

The study on the 0, 12 month vaccination schedule' of Healive inactivated hepatitis A vaccine in children / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the safety, immunogenicity and fit dosage of Healive inactivated hepatitis A vaccine (HAV) in children.</p><p><b>METHODS</b>A total of 85 susceptible aged 4 - 10 years with HAV seronegative children, had been enrolled from two adjacent villages in a county. The volunteers were randomized allocated into two groups and to receive a priming dose of 250 U/0.5 ml/dose or 500 U/1.0 ml/dose of Healive vaccine, produced by Sinovac Biotech Co, Ltd. A booster of the same dose was given at 12th month. Local and systemic side effects were examined and seroconversion rate as well as geometric mean titers of anti-HAV antibody were tested at 3-week, 12-month after the primary dose and at 1 month after the booster dose.</p><p><b>RESULTS</b>The vaccine was well tolerated in both groups. At 21 days after the primary dose, the seroconversion rates were 94.4%, 100.0% and geometric mean titers (GMT) were 195 mIU/ml and 370 mIU/ml in 250 U and 500 U groups respectively. At 12 months after the primary dose, the seroconversion rate of anti-HAV was 100.0%, and GMT raised to 361 mIU/ml, 456 mIU/ml (P > 0.05) respectively. One month after the booster dose, GMT raised to 14 893 mIU/ml, 21 696 mIU/ml.</p><p><b>CONCLUSION</b>GMT of the 0, 12 month schedule was higher than other schedule after the booster vaccination. The Healive inactivated vaccine can be used for emergency vaccination. The Healive inactivated vaccine produced by Sinovac Company Ltd was safe and highly immunogenic. Two hundred and fifty U/dose was considered appropriate for children.</p>