Clinical trial of inactivated polio vaccine

Domestic clinical trial: The clinical trial of this product registered in China adopts an open, randomized and controlled trial design. The immunogenicity of 600 healthy infant subjects who received three doses of basic immunization at the age of 2, 3 and 4 months, and then received 1 dose of booster immunization at the age of 18 months was evaluated by serum protection rate (the main end point of immunogenicity), and the safety was observed. The control vaccine is oral live attenuated polio vaccine (OPV) sugar pill. Inject the inoculation site into the anterolateral thigh muscle of the baby. In this experiment, the main end point of immunogenicity was tested by non-inferiority hypothesis, and it was confirmed by the analysis of ITT. The total analysis set randomly assigned to this group is the same as the safety data set, with 300 people in IPV group, 297 people in OPV group, 277 people in IPV group who have completed basic immunization and 282 people in OPV group. There are 209 ITT groups in IPV group and 207 ITT groups in OPV group. In PP population, IPV group was 186, OPV group was 193. The main results are summarized as follows: the main end point of immunogenicity: the serum protection rate, that is, the percentage of subjects with neutralizing antibody titer ≥ 8 (1/dilution multiple, 1/dil) after the third dose of immunization. According to the standard procedure of WHO /EPI/GEN93.9, the neutralized antibody was determined by cell culture micro neutralization method (cytopathic inhibition method). The results are shown in the following table. Secondary end point of immunogenicity: antibody titer and individual antibody titer ratio (post-immunization titer/pre-immunization titer, GMTR) of the two groups 1 month after the third dose inoculation. The results are shown in the following table. Considering the influence of mother-to-child transmission immunity, after correction, the percentage of subjects whose antibody titers in IPV group and OPV group increased by more than 4 times in the basic immunization stage was 93.9- 100.0%. According to the different antibody titers of subjects at baseline (≥8( 1/dil) and [8( 1/dil)), the seroconversion rate and antibody titers of the two groups were compared. The antibody titer before immunization was [8( 1/dil) or ≥ 8 (1). After correction in IPV group, the percentage of antibody titers in each subgroup increased by more than 4 times exceeded 87%. After completing three doses of basic immunization, the proportion of subjects whose titer of anti-polio antibody 1, 2 and 3 in IPV group of this product was at least 4 times higher than that before vaccination, which was 98.3%, 93.9% and 99.4% respectively. After the basic immunization 14- 16 months (before the booster immunization), the titer of anti-polio virus 1, 2, 3 antibody decreased, and the serum protection rates in IPV group were 88.3%, 83.2% and 82.7% respectively. The OPV group was 96.9%, 99.5% and 9 1. 1% respectively. At the age of 18 months, the subjects who received the basic immunization with this product received the booster immunization with 1 agent, and the serum protection rate against poliovirus 1, 2 and 3 reached 100%. Antibody titers were significantly higher than those before booster immunization and after basic immunization. The geometric mean titers (GMT) of anti-polio antibody 1, 2 and 3 before immunization were 44.5( 1/dil), 47.8( 1/dil) and 45.7( 1/dil), respectively. After immunization, it reached 2011.8 (1/dil), 1480.6( 1/dil) and 4393.4( 1/dil), respectively. The immunogenicity and safety of this product obtained from clinical trials registered in China are basically consistent with those of foreign clinical studies. For the safety data obtained in this experiment, please refer to the item of adverse reactions. Foreign clinical studies suggest that the immunity of this product can last for at least 5 years after the fourth vaccination (booster immunization after 3 doses of basic immunization 1 dose). However, the immune persistence of this product has not been studied in China; The clinical trial of IPV/OPV sequential vaccination immunization program has not yet been carried out.