[Abstract] to evaluate the immunogenicity of the low-dose inactivated domestic HAV vaccine ( Healive), 65 HAV susceptible children, aged 4-10 years old, had been enrooled from two adjacent villages in Pignshan county, Hebei Province. The volunteers were randomly divided into two groups, 32 of them received three doses of 125 U/0.5 ml vaccine intra-muscularly at 0,1,6 month interval and 250 U/0.5 ml dose of vaccine in other 33 children for two injections of 0,6 month schedule. The anti-HAV seroconversion rates and there titers were screened by ELISA Kit at 1, 6, 7 months after primary injection and one month later after boosting. All serum samples conllected were kept at -20°C and resred by one lot ELISA Kit The results showed that in two groups, Healive inactivated HAV vaccine had no marked side effect neither locally nor systemically. The anti-HAV seroconversion rates increased to 100%, and the GMTs were 531 miu/ml, 301 mIU/ml one month after boosting, the GMTs were 3170 mIU/ml and 5963 mIU/ml for 125 U/0.5 ml and 250u/0.5 mul vaccine respectively. 125 u/0.5 ml Healive inactivated HAV vaccine is applicable for children, it also can be considered as a reference dose to prepare HAV, HBV combined vaccine.
[Author] Ren Yin-hai, Chen Jiang-ting, Ma Shou-dong, et al
[key words] inactivated HAV vaccine, Immunogenicity, low dose vaccine
The study on two-dose injection method of the domestic inactivated hepatitis A vaccine applied in children and adults has been reported already [1-3], and the Newcomer-W and his associates have reported the immune effects of the Merck inactivated hepatitis A vaccine with three-dose injection method [5]; as for the report on the domestic hepatitis A vaccine with three-dose injection method, in order to observe the immunogenicity of the low-dose inactivated domestic HAV vaccine, the immunogenicity of the low-dose inactivated domestic HAV vaccine applied in children was observed, forming up the report as the follows:
Materials and Methods
1. Vaccine the experimental inactivated hepatitis A vaccine produced by Tangshan Yi’an Bioengineering Co., Ltd. was applied, containing the viral antigen 250U or 125U in each dosage, with the ratified number of 20010212.
2. Studied objects in the adjacent two villages of Pingshan County of Hebei Province with similar economic level, hygiene condition and living habit, 65 healthy children aged 4-10 years with the negative anti-HAV, negative HBsAg, and normal ALT and without the allergic history were chosen, with their average age at 7.7 and sex proportion of male to female at 1:0.91, who were divided into A and B group at random.
3. Vaccination method, dosage and schedule injection at the deltoid muscle of the upper arm, the 125U/dose was applied in Group A, with the 0, 1 and 6-month schedule. The first and second doses were the primary immunization and the third dose was the booster immunization. The 250U/dose was applied in Group B, with the 0, 6-month schedule. The first dose was the primary immunization, and the second dose was the booster immunization as well.
4. Side effect investigation all the vaccinated objects were observed for the side effects after 30 minutes of injection for the instant reaction, and the local (redness, swelling, warmth and pain) and systemic reactions (fever, hypodynamia, headache, dizzy, nausea, inappetence and rash) were observed after 8, 24, 48 and 72 hours.
5. Serology test took the venous blood sample when the people was in empty stomach, 3ml each time, aseptically separating the serum, stored at –20℃ for test. The standard HAV antibody was provided by the WHO, as the lyophilisation crystal, with the ratified number of 011107, and 1.0ml distilled water was filled to dissolve in each ampoule, with the concentration at 98.6IU/ml.
5.1 The qualitative test of anti-HAV: Adopt the ELISA Competitive Restriction Method, making use of ELISA agent box provided by Abbott Company, with ratified number of 8045DM200, and the sensitivity of 22mIU/ml. If the competitive restriction rate of the sample is more than 50%, it will be taken as the positive HAV antibody.
5.2 The quantitative test of anti-HAV: making use of the HA antibody agent ELISA calibrated by the standard HA antibody to measure, which was provided by Tangshan Yi’an Bioengineering Co., Ltd., with the ratified number of 011220, and the sensitivity of 103 mIU/ml. Within the proper dilution range, the linear regression on the dilution degree of the standard antibody provided by WHO and the OD value to gain the linear regression formula. According to the dilution degree of the sample and the measured OD value, which were returned back to the regressed formula, within the linear range of the OD value of the standard antibody, the mIU/ml of the antibody could be calculated out. Therefore, the anti-HAV level by this method should be consistent with that of the Abbott agent.
5.3 Liver functions Test The Laishi Method was applied for ALT test, which was normal when no more than 40U, produced by Beijing Beihua Kangtai Clinic Agent Co., Ltd., with the ratified number of 010622.
Results
1. Safety
After the inactivated hepatitis A vaccine was administrated, the instant reaction had not been found in these two groups, and the side effects were found in 8-24 hours, and disappeared in 48 hours, the local effects were redness (diameter less than 4mm), as well as the systematic effects were fever (both <37.5℃) (See Table 1).
Table 1 the side effects of the inactivated hepatitis A vaccine (local effects and systematic effects)
| Group |
Dosage
(U)
|
Tested
Persons |
First dose |
Second dose |
Third dose |
| Local |
Systematic |
Local |
Systematic |
Local |
Systematic |
| A |
125 |
32 |
0 |
0 |
0 |
1(3.1) |
0 |
0 |
| B |
250 |
33 |
1(3.0) |
1(3.0) |
0 |
0 |
- |
- |
Note: the data inside the bracket was the quantity of the persons, and the data outside the bracket was the occurrence rate of the side effects (%).
2. The antibody response in 4 weeks after the first dose of the inactivated hepatitis A vaccine
In 4 weeks after the inactivated hepatitis A was applied, the positive seroconversion rates of the anti-HAV of these two groups were 62.5%(20/32) and 93.9%(31/33), and the GMTs were 342mIU/ml and 382mIU/ml respectively. After the statistical treatment, the difference of the positive seroconversion rates of these two groups was significant statistically (x2=9.50, P<0.01), but the difference of the GMTs was not significant statistically (t=0.74, P>0.05)(See Table 2).
Table 2 The antibody response in 4 weeks after the first dose of the inactivated HA vaccine
| Group |
Vaccinated dosage |
Vaccinated persons |
Positive Seroconversion |
GMT
IU/ml
|
| Person |
% |
| A |
125U |
32 |
20 |
62.5 |
342 |
| B |
250U |
33 |
31 |
93.9 |
362 |
3. The antibody response in 6 months after the primary immunization of the inactivated hepatitis A vaccine
In 6 months after the inactivated hepatitis A was applied, 2 doses for Group A and 1 dose for Group B, the positive seroconversion rates of the anti-HAV of these two groups were 100%, and the GMTs were 531mIU/ml and 391mIU/ml respectively. After the statistical treatment, the difference was not significant statistically (t=0.32, P>0.05)(See Table 3).
Table 3 The antibody response in 6 months after the primary immunization of the inactivated HA vaccine
| Group |
Vaccinated dosage |
Schedule
(Month)
|
Vaccinated persons |
Positive Seroconversion |
GMT
IU/ml
|
| Person |
% |
| A |
125U |
0, 1, 6 |
32 |
20 |
62.5 |
342 |
| B |
250U |
0, 6 |
33 |
31 |
93.9 |
362 |
4. The antibody response in 1 month after the booster immunization of the inactivated hepatitis A vaccine
In one month after the booster immunization of the 125U of inactivated hepatitis A vaccine being administrated in Group A and 250U in Group B, the positive seroconversion rates of both groups reached to 100%, but GMT were 3170 mIU/ml and 5963 mIU/ml respectively. The effects of the anti-HAV titer were very obvious, with the differences statistically significant (t=2.65, P<0.01)(See Table 4).
Table 4 The antibody response in 6 months after the primary immunization of the inactivated HA vaccine
| Group |
Vaccinated dosage |
Schedule (Month)
|
Vaccinated persons |
Positive Seroconversion |
GMT mIU/ml
|
95% confidence interval
mIU/ml
|
| Person |
% |
| A |
125U |
0, 1, 6 |
32 |
32 |
100 |
3170 |
4562-2203 |
| B |
250U |
0, 6 |
33 |
33 |
100 |
5963 |
8233-4318 |
Conclusions
The side effects of the domestic inactivated hepatitis A vaccine with multiple doses applied in children were slight, being as transition, which proved that the domestic vaccine was safe.
The immnogenicity and the protective effects of the vaccine were relating to the quantity of the antigen. In 4 weeks after the 125U vaccine was applied, the positive seroconversion rate of the anti-HAV was 62.5%, significantly lower than 93.9% of the 250U group; in 6 months, the 125U group had been administrated for 2 doses of primary immunization, with the total antigen equivalent to that of the 250U group, the positive seroconversion rates of both groups were 100%, and the GMT were 531mIU/ml and 391mIU/ml respectively, without significant difference statistically, which indicated that, the immune level of the 125U group was as same as that of the 250U group after 6 months of primary immunization.
In the past studies [2-3], after the booster immunization of the domestic inactivated HA vaccine with the dosages of 250U, 500U and 1000U (0、1，0、3，0、 6 month schedules), the anti-HAV GMTs were reaching the high levels. In this study, after the three-doses of booster immunization, the anti-HAV GMT was 3170 mIU/ml, higher than 1973 mIU/ml of the 250U group at 0. 1-month schedule, but equivalent to 3265 mIU/ml of the 250U group at 0. 3-month schedule. This dosage of the hepatitis A vaccine was suitable for the combination of the hepatitis A and B.
(Thanks to Kagn Yunting, Cui Lianyun, Liu Zhongli, Li Haijun and Zong Xuemei for their participation)
References:
[1] Ren Aiguo, Ma Junrong, Feng Fumin, and Associates, The Study on the Safety and Immunogencity of the Domestic Inactivated Hepatitis A Vaccine [J], Chinese Journal of Experimental and Clinical virology, 2001, 15 (4): 357-359.
[2] Liu Xiaobai, Ren Dianhai, Zhang Yucheng, and Associates, The Study on Safety, Immnogencity and Vaccination Schedule of the Domestic Inactivated Hepatitis A Vaccine Applied in Children. [J], China Planning Immunology, 2002, 8 (1): 1-3.
[3] Ren Yinhai, Zhang Yucheng, Wu Wenting, and Associates, The Study on Safety and Immnogencity of the Domestic Inactivated Hepatitis A Vaccine Applied in Children at Low Ages [J], Chinese Journal of preventive medicine, 2002, 3 (3): 209-211.
[4] Newcorner W, Riein B, Rcid R, et al. Immunogenicity , safety and tolerability of varying doses and egimens of inactivated hepatitis A virus vaccine in Navajo children [J]. Fedintries infect Dis, 1994, 13(7): 640-642.
[5] Brucc L Lanis D. Snifbhan R. et al. Protection against hepatitis A by an inactivated vaccine [J] JAMA 271(17) 1328-1334
[6] Ze Wenyuan, Planning Immunology [M], Shanghai, Shanghai Science and Technology Works Press, 1997, 65.
Original: Chinese J of Vaccines and Immunization Dec. 2002,Vol.8 No.6
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