Immunological response to two hepatitis B vaccines administered in two different schedules
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《美国医学杂志》
1 Departments of Pediatrics, Seth GS Medical College and KEM Hospital, Parel, Mumbai, India
2 Departments of Microbiology, Seth GS Medical College and KEM Hospital, Parel, Mumbai, India
Abstract
Objectives. To evaluate the antibody response to a plasma derived hepatitis B vaccine containing pre-S and S antigens and a recombinant vaccine containing only S antigen and compare the two vaccines in 0, 1, 2 and 0, 1, 6, schedules Methods. One hundred fifty nine healthy infants were randomized to receive the vaccines in two different schedules. Anti HBs titers were estimated prior to the vaccination and then one-month following the second and third doses. Results. Both the vaccines produced a high rate of seroconversion and seroprotection. The antibody response was similar with both the vaccines and the 0, 1, 6, schedule induced a significantly higher antibody level than the 0, 1, 2, schedule. Conclusion. 0, 1, 6 schedule produces a higher antibody level than 0, 1, 2 schedule though both the schedules have good seroconversion and seroprotection rates with both the vaccines.
Keywords: Surface antigen; Pre-S antigen; Antibody; Hepatitis B vaccine
There appears to be a consensus regarding the need for universal immunization against hepatitis B following the recommendations of organizations like the WHO, the Indian Academy of Pediatrics and the American Academy of Pediatrics.[1],[2],[3] The need for a booster is under debate with recent suggestions that it may not be necessary at all. Since the introduction of the first vaccine against hepatitis B in 1982, many brands have entered the market. The various manufacturers provide a slight variation in the antigen particle and recommend different schedules for immunization.[4] The pre-S antigens in some vaccines are claimed to provide a better immune response than the vaccines containing only S-antigen. In this context, we analyzed two hepatitis B vaccines, one of them containing pre- S antigens, in two different schedules in healthy infants.
Materials and Methods
Healthy infants (0-12 months of age), born at term attending the well baby clinic of a teaching hospital were included in this prospective study, which lasted for 18 months. An informed consent was taken from the parent or the legal guardian. The exclusion criteria included: HBsAg positive mother, baby's age more than one year at the time of enrollment, subjects who had already received a hepatitis B vaccine, immunoglobulin or a blood product, and an acute illness contraindicating routine immunization. The infants were distributed into the following four groups randomly. Group I: received vaccine A, a plasma derived vaccine containing 3mg of surface antigen in 0.5 ml on a schedule of 0, 1, 2 months. The constituents of the vaccine were: S antigen-52.63%, pre-S 1 - 6.30%, & pre-S 2 -18.87%. Group II: received vaccine B, a recombinant vaccine containing 10 mg of only S antigen in 0.5 ml on a schedule of 0, 1, 2 months. Group III: received vaccine A on a schedule of 0, 1, 6 months. Group IV: received vaccine B on a schedule of 0, 1, 6 months.
Pre-vaccination blood samples were collected from the mother and the baby pair and tested for HBsAg. The anti- HBsAg antibody levels were estimated on three occasions: before vaccination, one month after the second dose and one month after the third dose. The vaccine was administered intramuscularly into the lateral aspect of the thigh. Care was taken not to inject another childhood vaccine into the same thigh at one sitting. Parents were requested to report adverse events. The Ethics Committee's approval was obtained for the study.
Laboratory methods : All the collected samples of sera were stored at - 20°C until the end of the trial and analyzed simultaneously. HBsAg was estimated by ELISA. The anti-HBsAg antibody was assayed using ELAgen Anti HBs Quantitative Kit 3rd generation (Biochem Immunosystems Italia S.P.A) based on sandwich enzyme linked immunosorbant assay. For the purpose of the study, the following terminologies were used. Seroconversion - An anti-HBs titer equal to or greater than 1 IU/L, Seroprotection - An anti-HBs titer equal to or greater than 10 IU/L. [6],[7]
Statistical methods : Proportions were compared with Chi-square test. Student t test was used to analyze the geometric mean titer (GMT) of antibody after the third dose of vaccine. P value of <0.05 was considered to be statistically significant.
Results
One hundred sixty one mothers with their 163 children were enrolled in the study. Four mothers who tested positive for HBsAg and their four children (2 HBsAg positive and 2 negative) were excluded. The final analysis was done on a total of 157 mothers and their 159 study children. The age and sex distribution of four groups containing 41, 40, 38 and 40 in-group I, II, III, & IV respectively were comparable table1. Children who completed the follow up were 38 in group I (92.68%), 35 in group II (87.5%), 27 in group III (71.05%) and 34 in group IV (85%). Though the follow up was better in 0, 1, 2 schedule (group I & II) this difference was not statistically significant. Seroconversion rate for vaccine A after the first two doses was 73.24% and for vaccine B was 81.54%. Seroprotection rates were 64.79% and 69.23% for vaccine A and vaccine B respectively.
The final anti-HBsAg levels are shown in table2. The GMTs were similar with both the vaccines in either of the schedules but a significantly higher GMT was observed with the 0, 1, 6 schedule than in the 0, 1, 2 schedule
Both the vaccines were found to be safe during the study. No local or systematic reaction of a serious nature was reported.
Discussion
Our study used two commercially available vaccines in their recommended doses. Both the vaccines produced a high rate of seroconversion as well as seroprotection. The GMTs were lower in our study (77.94 IU/L and 203.4 IU/L with vaccine A and 98.33 IU/L and 220.4 IU/L with vaccine B) than in others. We have found a wide variation in the GMTs reported by different workers. GMTs of 33 IU/L with 5 mg dose and 77 IU/L with 10 mg dose was reported by Oon CJ et al when the vaccine was given to neonates in a 0, 1, 2 schedule.[8] GMTs of 880 IU/L and 1641 IU/L were reported by Goldfarb et al with 5 mg & 10 μg of the vaccine respectively administered at 0, 2, 4 schedule in infants.[9] A very high GMT value of 2643 IU/L was reported with 0, 1, 2 schedule of 10 mg doses in infants in an Indian study.[10] GMT value as high as 19,912 IU/L was reported in young adults with 0, 1, 6 schedule with 10 mg vaccine by Jilg W et al[11] The cause for these variable levels of antibodies needs to be found.
As in our study, a higher seroprotection level and GMT with a 0, 1, 6 schedule than after a 0, 1, 2 schedule have been reported by other workers also.[11], [12] These findings clearly suggest that a slower schedule should be followed for routine immunization of infants except when a faster protection is desired as in neonates exposed to the virus from the mother.
The amount of surface antigen in the vaccine also determines the GMT attained. In 1989 Tron et al reported a GMT of 90.4 IU/L, 96.4 IU/L, 166.6 IU/L and 213.7 IU/L with 2 mg, 5 mg, 10 mg, and 20 mg doses of the vaccine respectively in a 0, 1, 2 schedule indicating that the GMT is directly proportional to the dose of the vaccine used.[13] In our study however, vaccine A containing only 3mg of antigen per dose and vaccine B containing 10 mg of the antigen per dose produced a similar geometric mean concentration of the antibody in spite of the difference in the doses in both the schedules. This could perhaps suggest that the presence of pre-S component in vaccine A enhances the production of anti-HBsAg antibodies through a mechanism that has not been fully explained.
As early as 1985 and 1986 Milich et al reported the possible role of pre-S and pre-S[2] antigen in vaccination against hepatitis B.[14],[15] They had observed that the non-responsiveness to S region can be circumvented by addition of pre -S antigens to the vaccine. Clement et al contradicted this and observed that a small amount of pre-S 2 antigen in the combination vaccine did not enhance the immune response to the S antigen.[6]
The study has some limitations. The sample size is small. The infants were taken into the study when they attended the well baby clinic for routine immunization. This resulted in the wide range for the age groups (1/2 -12 months). The anti-HBsAg levels in the mothers were not estimated. Hence, the effect of antibodies in the mother on immunization in the child could not be evaluated. As currently the need for boosters is doubtful, the clinical relevance of the difference in the GMT is questionable. The vaccines were given in the dose prescribed by the manufacturers and hence the antigen content was different in the two vaccines used. We suggest a larger study with equal dosages of two vaccines with estimation of antibodies to pre-S antigens to confirm our findings.
Contribution of Authors
Girisha KM was involved in designing, co-ordinating and conducting the study. He was also the clinician involved in examining the infants and interpretation of results. He drafted the manuscript. Jaishree R Kamat was involved in designing, supervising and guiding the study. She was also actively involved in preparing and editing the manuscript. Gita Nataraj was involved in designing the study and supervising the laboratory methods.
References
1. Lemon SM, Thomas DL. Vaccines to prevent viral hepatitis. N Engl J Med 1997; 336 : 196-204.
2. Mittal SK, Rao S, Kumari S, Aggarwal V, Prakash C, Thirupuram S. Simultaneous administration of hepatitis B vaccine with other EPI vaccines. Indian J Pediatr 1994; 61: 183-188.
3. Committee on infectious diseases. Universal hepatitis B immunization. Pediatrics 1992; 89: 795-800.
4. Storch GA, Halsey NA, Koff RS, Shapiro CN, Greenberg DP. Proceedings of the symposium at the American Academy of Pediatrics Annual Meeting. Pediatr Infect Dis J 1993; 12: 427-453.
5. Wilson JN, Nokes DJ. Do we need 3 doses of hepatitis B vaccine Vaccine 1999; 17: 2667-2673.
6. Clements ML, Miskovsky E, Davidson M et al. Effect of age on the immunogenicity of yeast recombinant hepatitis B vaccine containing surface antigen (S) or pre S2+ S antigen. J Infect Dis 1994; 170 : 510-516.
7. Jack AD, Hall AJ, Maine M, Mendy M, Whittle WC. What level of hepatitis B antibody is protective J Infect Dis 1999; 179:489-492.
8. Oon CJ, Tan KL, Goh KT et al. Evolution of a low dose Hepatitis B vaccine given within a childhood immunization program in Singapore. J Infect 1986; 13 : 255-267.
9. Goldfarb J, Medendorp SV, Garcia H, Nagamori K, Rathfon H, Krause D. Comparison study of the immunogenicity and safety of 5 and 10 mg dosages of a recombinant hepatitis B vaccine in healty infants. Pediatr Infect Dis J 1996; 764-767.
10. Kumar TS, Abraham P, Raghuraman S, Cherian T. Immunogenicity of indigenous recombinant hepatitis B vaccine in infants following a 0,1,2- month vaccination schedule. Indian Pediatr 2000; 37 : 75-80.
11. Jilg W, Schmidt M, Deinhardt. Vaccination against hepatitis B Comparison of three different vaccination schedules. J Infect Dis 1989; 160 : 766-769.
12. Halsey NA, Moulton LH, O'Donovan JC et al. Hepatitis B vaccine administered to children and adolescents at yearly intervals. Pediatrics 1999; 103: 1243-1247.
13. Tron F, Degos F, Brechot C et al. Randomized dose range study of a recombinant hepatitis B vaccine produced in mammalian cells and containing the S and Pre S2 sequences. J Infect Dis 1989; 160:199-204.
14. Milich DR, Mc Lachlan A, Chisari FV, Kent SBH, Thornton BT. Immune response to the pre S1 region of the hepatitis B surface antigen (HBs Ag) : A pre -S1 specific T cell response can bypass no responsiveness to the pre -S2 and S regions of HBs Ag. J Immunol 1986; 137: 315-322.
15. Milich DR, Thornton GB, Neurath AR et al. Enhanced immunogenicity of the pre -S region of hepatitis B surface antigen. Science 1985; 228 : 1195-99.(Girisha KM, Kamat JR, Nat)
2 Departments of Microbiology, Seth GS Medical College and KEM Hospital, Parel, Mumbai, India
Abstract
Objectives. To evaluate the antibody response to a plasma derived hepatitis B vaccine containing pre-S and S antigens and a recombinant vaccine containing only S antigen and compare the two vaccines in 0, 1, 2 and 0, 1, 6, schedules Methods. One hundred fifty nine healthy infants were randomized to receive the vaccines in two different schedules. Anti HBs titers were estimated prior to the vaccination and then one-month following the second and third doses. Results. Both the vaccines produced a high rate of seroconversion and seroprotection. The antibody response was similar with both the vaccines and the 0, 1, 6, schedule induced a significantly higher antibody level than the 0, 1, 2, schedule. Conclusion. 0, 1, 6 schedule produces a higher antibody level than 0, 1, 2 schedule though both the schedules have good seroconversion and seroprotection rates with both the vaccines.
Keywords: Surface antigen; Pre-S antigen; Antibody; Hepatitis B vaccine
There appears to be a consensus regarding the need for universal immunization against hepatitis B following the recommendations of organizations like the WHO, the Indian Academy of Pediatrics and the American Academy of Pediatrics.[1],[2],[3] The need for a booster is under debate with recent suggestions that it may not be necessary at all. Since the introduction of the first vaccine against hepatitis B in 1982, many brands have entered the market. The various manufacturers provide a slight variation in the antigen particle and recommend different schedules for immunization.[4] The pre-S antigens in some vaccines are claimed to provide a better immune response than the vaccines containing only S-antigen. In this context, we analyzed two hepatitis B vaccines, one of them containing pre- S antigens, in two different schedules in healthy infants.
Materials and Methods
Healthy infants (0-12 months of age), born at term attending the well baby clinic of a teaching hospital were included in this prospective study, which lasted for 18 months. An informed consent was taken from the parent or the legal guardian. The exclusion criteria included: HBsAg positive mother, baby's age more than one year at the time of enrollment, subjects who had already received a hepatitis B vaccine, immunoglobulin or a blood product, and an acute illness contraindicating routine immunization. The infants were distributed into the following four groups randomly. Group I: received vaccine A, a plasma derived vaccine containing 3mg of surface antigen in 0.5 ml on a schedule of 0, 1, 2 months. The constituents of the vaccine were: S antigen-52.63%, pre-S 1 - 6.30%, & pre-S 2 -18.87%. Group II: received vaccine B, a recombinant vaccine containing 10 mg of only S antigen in 0.5 ml on a schedule of 0, 1, 2 months. Group III: received vaccine A on a schedule of 0, 1, 6 months. Group IV: received vaccine B on a schedule of 0, 1, 6 months.
Pre-vaccination blood samples were collected from the mother and the baby pair and tested for HBsAg. The anti- HBsAg antibody levels were estimated on three occasions: before vaccination, one month after the second dose and one month after the third dose. The vaccine was administered intramuscularly into the lateral aspect of the thigh. Care was taken not to inject another childhood vaccine into the same thigh at one sitting. Parents were requested to report adverse events. The Ethics Committee's approval was obtained for the study.
Laboratory methods : All the collected samples of sera were stored at - 20°C until the end of the trial and analyzed simultaneously. HBsAg was estimated by ELISA. The anti-HBsAg antibody was assayed using ELAgen Anti HBs Quantitative Kit 3rd generation (Biochem Immunosystems Italia S.P.A) based on sandwich enzyme linked immunosorbant assay. For the purpose of the study, the following terminologies were used. Seroconversion - An anti-HBs titer equal to or greater than 1 IU/L, Seroprotection - An anti-HBs titer equal to or greater than 10 IU/L. [6],[7]
Statistical methods : Proportions were compared with Chi-square test. Student t test was used to analyze the geometric mean titer (GMT) of antibody after the third dose of vaccine. P value of <0.05 was considered to be statistically significant.
Results
One hundred sixty one mothers with their 163 children were enrolled in the study. Four mothers who tested positive for HBsAg and their four children (2 HBsAg positive and 2 negative) were excluded. The final analysis was done on a total of 157 mothers and their 159 study children. The age and sex distribution of four groups containing 41, 40, 38 and 40 in-group I, II, III, & IV respectively were comparable table1. Children who completed the follow up were 38 in group I (92.68%), 35 in group II (87.5%), 27 in group III (71.05%) and 34 in group IV (85%). Though the follow up was better in 0, 1, 2 schedule (group I & II) this difference was not statistically significant. Seroconversion rate for vaccine A after the first two doses was 73.24% and for vaccine B was 81.54%. Seroprotection rates were 64.79% and 69.23% for vaccine A and vaccine B respectively.
The final anti-HBsAg levels are shown in table2. The GMTs were similar with both the vaccines in either of the schedules but a significantly higher GMT was observed with the 0, 1, 6 schedule than in the 0, 1, 2 schedule
Both the vaccines were found to be safe during the study. No local or systematic reaction of a serious nature was reported.
Discussion
Our study used two commercially available vaccines in their recommended doses. Both the vaccines produced a high rate of seroconversion as well as seroprotection. The GMTs were lower in our study (77.94 IU/L and 203.4 IU/L with vaccine A and 98.33 IU/L and 220.4 IU/L with vaccine B) than in others. We have found a wide variation in the GMTs reported by different workers. GMTs of 33 IU/L with 5 mg dose and 77 IU/L with 10 mg dose was reported by Oon CJ et al when the vaccine was given to neonates in a 0, 1, 2 schedule.[8] GMTs of 880 IU/L and 1641 IU/L were reported by Goldfarb et al with 5 mg & 10 μg of the vaccine respectively administered at 0, 2, 4 schedule in infants.[9] A very high GMT value of 2643 IU/L was reported with 0, 1, 2 schedule of 10 mg doses in infants in an Indian study.[10] GMT value as high as 19,912 IU/L was reported in young adults with 0, 1, 6 schedule with 10 mg vaccine by Jilg W et al[11] The cause for these variable levels of antibodies needs to be found.
As in our study, a higher seroprotection level and GMT with a 0, 1, 6 schedule than after a 0, 1, 2 schedule have been reported by other workers also.[11], [12] These findings clearly suggest that a slower schedule should be followed for routine immunization of infants except when a faster protection is desired as in neonates exposed to the virus from the mother.
The amount of surface antigen in the vaccine also determines the GMT attained. In 1989 Tron et al reported a GMT of 90.4 IU/L, 96.4 IU/L, 166.6 IU/L and 213.7 IU/L with 2 mg, 5 mg, 10 mg, and 20 mg doses of the vaccine respectively in a 0, 1, 2 schedule indicating that the GMT is directly proportional to the dose of the vaccine used.[13] In our study however, vaccine A containing only 3mg of antigen per dose and vaccine B containing 10 mg of the antigen per dose produced a similar geometric mean concentration of the antibody in spite of the difference in the doses in both the schedules. This could perhaps suggest that the presence of pre-S component in vaccine A enhances the production of anti-HBsAg antibodies through a mechanism that has not been fully explained.
As early as 1985 and 1986 Milich et al reported the possible role of pre-S and pre-S[2] antigen in vaccination against hepatitis B.[14],[15] They had observed that the non-responsiveness to S region can be circumvented by addition of pre -S antigens to the vaccine. Clement et al contradicted this and observed that a small amount of pre-S 2 antigen in the combination vaccine did not enhance the immune response to the S antigen.[6]
The study has some limitations. The sample size is small. The infants were taken into the study when they attended the well baby clinic for routine immunization. This resulted in the wide range for the age groups (1/2 -12 months). The anti-HBsAg levels in the mothers were not estimated. Hence, the effect of antibodies in the mother on immunization in the child could not be evaluated. As currently the need for boosters is doubtful, the clinical relevance of the difference in the GMT is questionable. The vaccines were given in the dose prescribed by the manufacturers and hence the antigen content was different in the two vaccines used. We suggest a larger study with equal dosages of two vaccines with estimation of antibodies to pre-S antigens to confirm our findings.
Contribution of Authors
Girisha KM was involved in designing, co-ordinating and conducting the study. He was also the clinician involved in examining the infants and interpretation of results. He drafted the manuscript. Jaishree R Kamat was involved in designing, supervising and guiding the study. She was also actively involved in preparing and editing the manuscript. Gita Nataraj was involved in designing the study and supervising the laboratory methods.
References
1. Lemon SM, Thomas DL. Vaccines to prevent viral hepatitis. N Engl J Med 1997; 336 : 196-204.
2. Mittal SK, Rao S, Kumari S, Aggarwal V, Prakash C, Thirupuram S. Simultaneous administration of hepatitis B vaccine with other EPI vaccines. Indian J Pediatr 1994; 61: 183-188.
3. Committee on infectious diseases. Universal hepatitis B immunization. Pediatrics 1992; 89: 795-800.
4. Storch GA, Halsey NA, Koff RS, Shapiro CN, Greenberg DP. Proceedings of the symposium at the American Academy of Pediatrics Annual Meeting. Pediatr Infect Dis J 1993; 12: 427-453.
5. Wilson JN, Nokes DJ. Do we need 3 doses of hepatitis B vaccine Vaccine 1999; 17: 2667-2673.
6. Clements ML, Miskovsky E, Davidson M et al. Effect of age on the immunogenicity of yeast recombinant hepatitis B vaccine containing surface antigen (S) or pre S2+ S antigen. J Infect Dis 1994; 170 : 510-516.
7. Jack AD, Hall AJ, Maine M, Mendy M, Whittle WC. What level of hepatitis B antibody is protective J Infect Dis 1999; 179:489-492.
8. Oon CJ, Tan KL, Goh KT et al. Evolution of a low dose Hepatitis B vaccine given within a childhood immunization program in Singapore. J Infect 1986; 13 : 255-267.
9. Goldfarb J, Medendorp SV, Garcia H, Nagamori K, Rathfon H, Krause D. Comparison study of the immunogenicity and safety of 5 and 10 mg dosages of a recombinant hepatitis B vaccine in healty infants. Pediatr Infect Dis J 1996; 764-767.
10. Kumar TS, Abraham P, Raghuraman S, Cherian T. Immunogenicity of indigenous recombinant hepatitis B vaccine in infants following a 0,1,2- month vaccination schedule. Indian Pediatr 2000; 37 : 75-80.
11. Jilg W, Schmidt M, Deinhardt. Vaccination against hepatitis B Comparison of three different vaccination schedules. J Infect Dis 1989; 160 : 766-769.
12. Halsey NA, Moulton LH, O'Donovan JC et al. Hepatitis B vaccine administered to children and adolescents at yearly intervals. Pediatrics 1999; 103: 1243-1247.
13. Tron F, Degos F, Brechot C et al. Randomized dose range study of a recombinant hepatitis B vaccine produced in mammalian cells and containing the S and Pre S2 sequences. J Infect Dis 1989; 160:199-204.
14. Milich DR, Mc Lachlan A, Chisari FV, Kent SBH, Thornton BT. Immune response to the pre S1 region of the hepatitis B surface antigen (HBs Ag) : A pre -S1 specific T cell response can bypass no responsiveness to the pre -S2 and S regions of HBs Ag. J Immunol 1986; 137: 315-322.
15. Milich DR, Thornton GB, Neurath AR et al. Enhanced immunogenicity of the pre -S region of hepatitis B surface antigen. Science 1985; 228 : 1195-99.(Girisha KM, Kamat JR, Nat)