Antibody Responses to Four Haemophilus influenzae Type b Conjugate Vaccines H.
K\l=a"\yhty,PhD; J. Eskola, MD;
\s=b\ Serum enzae
antibody
H.
responses to four
Peltola, MD;
P-R.
R\l=o"\nnberg,RN;
Haemophilus influ-
type b capsular polysaccharide-protein conjugate vaccines (PRP-D, HbOC, C7p, and PRP-T) were studied and compared in 175 infants, 85 adults, and 140 2-year-old children. Antibodies to the H influenzae type b polysaccharide
vaccines were determined with a Farr-type radioimmunoassay. The infants received two doses of vaccine at the ages of 4 and 6 months. After the first dose of vaccine, the geometric mean antibody concentration measured at the age of 6 months was 0.09 to 0.10 mg/L, only marginally higher than that measured before immunization in all infants who had received PRP-D, HbOC, or C7p but increased to 0.82 mg/L in those who had received PRP-T. One month after the second dose, the geometric mean antibody concentration was increased in all vaccine groups. No significant differences were noted between recipients of HbOC, C7p, or PRP-T (geometric mean antibody concentrations, 4.32,3.10, and 6.10 mg/L, respectively), whereas the PRP-D recipients had a significantly lower geometric mean antibody concentration (0.63 mg/L). In contrast, PRP-D, HbOC, C7p, and PRP-T were all highly immunogenic in adults, with no differences noted among them. The 2-year-old children also responded to one dose of these vaccines with a high antibody concentration.
(AJDC. 1991;145:223-227)
I-iaemophilus influenzae type b (Hib)inis the most common cause
of bacteremic infections
infants and young
children.1,2 Although mortality due to these diseases has
decreased to less than 5% as a result of efficient treatment, the occurrence of severe sequelae in survivors remains vaccine that could prevent this morbidity would high.3"5 A be therefore welcome. Early in this century, covalent coupling of the capsular polysaccharide (PS) of Pneumococcus to a protein carrier was described.6,7 Many variations of such conjugate vaccines are possible depending on the protein carrier, the length of the PS chain, the linker, and the coupling procedure. Several groups and manufacturers have produced vaccines against Hib that incorporate some of these variations. Thus, PRP-D is composed of PS coupled to diphtheria toxoid via an adipic acid linker, as described originally by Schneerson et al8 and
Accepted for publication May 30, 1990. From the Department of Bacteriology, National Public Health
In-
stitute, Helsinki, Finland. Reprint requests to National Public Health Institute, Manner\x=req-\ heimintie 166, 00300 Helsinki, Finland (Dr Eskola).
E.
Kela, RN;
V.
Karanko, RN;
L.
Saarinen, MSc
Gordon.9 A related preparation (PRP-T) that employs teta¬
toxoid instead of diphtheria toxoid was originally de¬ scribed by Chu et al.10 HbOC contains oligosaccharides (OSs) directly coupled by reductive animation to a nontoxic variant diphtheria toxin, CRM197; the OSs are activated biterminally so that they can bind to the protein atbothends.11 Porter Anderson (University of Rochester [NY]) has pre¬ pared a series of vaccines, eg, C7p, in which umterminally activated OSs are coupled to the protein (either diphtheria toxoid or CRM197) at one end.12 In PRP-OMP, PS is coupled by a bigeneric linker to an outer membrane protein -complex isolated from Neisseria meningitidis group B, type 2a.13 All of these vaccines have been shown to be immunogenic in human infants.11,14"18 A comparison of the vac¬ cines is difficult based on the published data, as there are no standardized assays for anti-Hib PS and results from different laboratories may not be directly comparable.19"21 Separate studies, however, suggest differences in immu¬ nogenicity. Furthermore, the extent to which the immu¬ nogenicity of the vaccines in adults or older children would predict immunogenicity in infants is unclear. To consolidate the data base, we have compared, under similar conditions, the immunogenicity and reactogenicity of four Hib conjugate vaccines in infants immunized at 4 and 6 months of age, adults, and 2-year-old children; some of the data have been previously published,22,23 but they are presented herein together with the new data to facilitate comparison. nus
PATIENTS AND METHODS
Vaccines, Vaccinées, and the Vaccination Schedules
The Hib vaccines used
are
listed in Table 1. The vaccination
protocol was approved by the Ethical Committee of the National
Public Health Institute, Helsinki, Finland. Informed consent was obtained from the adult vaccinées or from the parents of children and infants. Healthy infants were recruited at the age of 3 months from the child health centers of two towns: Joensuu and Kerava. Seventytwo infants received PRP-D, 46 received HbOC, 32 received C7p, and 25 received PRP-T at the ages of 4 and 6 months. At the age of 4 months, they also received their second dose of diphtheriapertussis-tetanus vaccine (National Public Health Institute); at the age of 6 months, they received their first dose of poliomyelitis vaccine (inactivated poliovirus vaccine; RIVM, Bilthoven, the Netherlands). The Hib vaccines were given intramuscularly into the right buttock, and the diphtheria-pertussis-tetanus and in¬ activated poliovirus vaccines were administered intramuscularly into the left buttock. Healthy, mostly female young adults received intramuscular injections into the left arm of PRP-D (n 27), HbOC (n 19), C7p
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Calgary User on 05/25/2015
=
=
Table
.—Haemophilus influenzae Type (Hib) Vaccines Used in a Comparative Immunogenicity Trial Among Infants, Children, and Adults.
Lot No.
Vaccine PRP-D
5L294
HbOC
4102,4163* BrH-5-12, 1 lot
PRP-T
S-1890
Ine, Swiftwater, Pa Praxis Biologies Ine,
Rochester, NY Porter Anderson, Rochester, NY
6174
C7p
Manufacturer Connaught Laboratories
Institute Merieux, Lyons, France
Spacer
Amount of Hib Polysaccharide per Dose, µg
Polysaccharide Ratio
6 carbon
20
1.25
None
10
2.5
None
5
5.0
10
1.88
Type of
Saccharide Sized
Protein-to-
polysaccharidet 20-unit
oligosaccharide 7-unit
oligosaccharide Native
6 carbon
polysaccharide
*Lot4163
was used in infants and lots 5L294 and 4102 were used in adults and children. tThe molecular weight of the polysaccharide is heat sized to 200 to 2000 kd. tLot 61 74 was used in infants and lots BrH-5-12 and 6174 were used in adults and children.
( 18), or PRP-T ( 21). No other vaccinations were given at the same time. Children were immunized intramuscularly into the right buttock at 23 to 25 months of age with PRP-D (n 54), HbOC (n 56), or C7p (n 30). The children in the PRP-D group also received bivalent (groups A and C) meningococcal vaccine (Connaught Laboratories Ine, Swittwater, Pa) and/or 23-valent pneumococcal vaccine (Pneumovax, Merck Sharp & Dohme, West Point, Pa); these vaccines have been shown to have no effect on the response to a Hib conjugate vaccine or to Hib CPS vac¬ =
=
=
=
=
cine.22,24
Serum Samples Blood samples were obtained from infants before the first and second doses and 1 month after the second dose, ie, at 4, 6, and 7 months of age. Blood samples were obtained from children and adults before and 1 month after vaccination. The samples were preserved at -20°C until testing.
Follow-up of Adverse Reactions
The vaccinées were observed for at least 15 minutes after each vaccination. The vaccinées or their parents were given a special form to be completed 6, 12, 24, and 48 hours after vaccination. The rectal temperature, any systemic reaction, and description of local reactions at the injection site were recorded on this form.
Serologie Methods
Antibodies to the Hib PS were measured by a Farr-type rawith the use of a tyramine derivative of Hib dioimmunoassay25 PS prepared by Rachel Schneerson (National Institutes of Health, Bethesda, Md) for iodination. The reference serum was also re¬ ceived from Rachel Schneerson.
Statistical
Analysis
The geometric mean antibody concentrations (GMCs) were cal¬ culated with 0.06 mg/L as the lower and 320 mg/L as the higher limit of detection. Analysis of variance, Duncan's test at P .05 (both tests need log-transformed data), and 2 test were used for differences in the anti-Hib PS antibody concentrations at each =
sampling point.
RESULTS
Reactogenicity of the Hib Vaccines Irritability was the most common adverse effect among infants, reported in 41% to 60% of the vaccinées after the first dose and in 16% to 32% after the second dose. Fever was uncommon, detected in 2% to 5% of infants, regard¬ less of age at the time of vaccination. Local soreness was also uncommon. No significant differences were noted be¬ tween the vaccine groups regarding the frequency of re¬
actions. None of the adults or 2-year-old children had a fever after any of the vaccines. Local redness was reported in three children, and local soreness was reported in 14 chil-
dren, all of whom had received the PRP-D vaccine together with meningococcal vaccine and most of whom (n ll) had also received the Pneumovax vaccine. These reactions were probably due to the latter vaccine.22 =
Immunogenicity in Infants Infants were immunized at 4 and 6 months of age. The preimmunization anti-Hib PS concentrations were similar (0.07 to 0.09 mg/L) in each group (Fig 1); few children ac¬ tually had measurable antibody levels (Fig 2). Two months after the first dose, at the age of 6 months, the anti-Hib PS concentrations differed significantly in the four vaccine groups (P
K\l=a"\yhty,PhD; J. Eskola, MD;
\s=b\ Serum enzae
antibody
H.
responses to four
Peltola, MD;
P-R.
R\l=o"\nnberg,RN;
Haemophilus influ-
type b capsular polysaccharide-protein conjugate vaccines (PRP-D, HbOC, C7p, and PRP-T) were studied and compared in 175 infants, 85 adults, and 140 2-year-old children. Antibodies to the H influenzae type b polysaccharide
vaccines were determined with a Farr-type radioimmunoassay. The infants received two doses of vaccine at the ages of 4 and 6 months. After the first dose of vaccine, the geometric mean antibody concentration measured at the age of 6 months was 0.09 to 0.10 mg/L, only marginally higher than that measured before immunization in all infants who had received PRP-D, HbOC, or C7p but increased to 0.82 mg/L in those who had received PRP-T. One month after the second dose, the geometric mean antibody concentration was increased in all vaccine groups. No significant differences were noted between recipients of HbOC, C7p, or PRP-T (geometric mean antibody concentrations, 4.32,3.10, and 6.10 mg/L, respectively), whereas the PRP-D recipients had a significantly lower geometric mean antibody concentration (0.63 mg/L). In contrast, PRP-D, HbOC, C7p, and PRP-T were all highly immunogenic in adults, with no differences noted among them. The 2-year-old children also responded to one dose of these vaccines with a high antibody concentration.
(AJDC. 1991;145:223-227)
I-iaemophilus influenzae type b (Hib)inis the most common cause
of bacteremic infections
infants and young
children.1,2 Although mortality due to these diseases has
decreased to less than 5% as a result of efficient treatment, the occurrence of severe sequelae in survivors remains vaccine that could prevent this morbidity would high.3"5 A be therefore welcome. Early in this century, covalent coupling of the capsular polysaccharide (PS) of Pneumococcus to a protein carrier was described.6,7 Many variations of such conjugate vaccines are possible depending on the protein carrier, the length of the PS chain, the linker, and the coupling procedure. Several groups and manufacturers have produced vaccines against Hib that incorporate some of these variations. Thus, PRP-D is composed of PS coupled to diphtheria toxoid via an adipic acid linker, as described originally by Schneerson et al8 and
Accepted for publication May 30, 1990. From the Department of Bacteriology, National Public Health
In-
stitute, Helsinki, Finland. Reprint requests to National Public Health Institute, Manner\x=req-\ heimintie 166, 00300 Helsinki, Finland (Dr Eskola).
E.
Kela, RN;
V.
Karanko, RN;
L.
Saarinen, MSc
Gordon.9 A related preparation (PRP-T) that employs teta¬
toxoid instead of diphtheria toxoid was originally de¬ scribed by Chu et al.10 HbOC contains oligosaccharides (OSs) directly coupled by reductive animation to a nontoxic variant diphtheria toxin, CRM197; the OSs are activated biterminally so that they can bind to the protein atbothends.11 Porter Anderson (University of Rochester [NY]) has pre¬ pared a series of vaccines, eg, C7p, in which umterminally activated OSs are coupled to the protein (either diphtheria toxoid or CRM197) at one end.12 In PRP-OMP, PS is coupled by a bigeneric linker to an outer membrane protein -complex isolated from Neisseria meningitidis group B, type 2a.13 All of these vaccines have been shown to be immunogenic in human infants.11,14"18 A comparison of the vac¬ cines is difficult based on the published data, as there are no standardized assays for anti-Hib PS and results from different laboratories may not be directly comparable.19"21 Separate studies, however, suggest differences in immu¬ nogenicity. Furthermore, the extent to which the immu¬ nogenicity of the vaccines in adults or older children would predict immunogenicity in infants is unclear. To consolidate the data base, we have compared, under similar conditions, the immunogenicity and reactogenicity of four Hib conjugate vaccines in infants immunized at 4 and 6 months of age, adults, and 2-year-old children; some of the data have been previously published,22,23 but they are presented herein together with the new data to facilitate comparison. nus
PATIENTS AND METHODS
Vaccines, Vaccinées, and the Vaccination Schedules
The Hib vaccines used
are
listed in Table 1. The vaccination
protocol was approved by the Ethical Committee of the National
Public Health Institute, Helsinki, Finland. Informed consent was obtained from the adult vaccinées or from the parents of children and infants. Healthy infants were recruited at the age of 3 months from the child health centers of two towns: Joensuu and Kerava. Seventytwo infants received PRP-D, 46 received HbOC, 32 received C7p, and 25 received PRP-T at the ages of 4 and 6 months. At the age of 4 months, they also received their second dose of diphtheriapertussis-tetanus vaccine (National Public Health Institute); at the age of 6 months, they received their first dose of poliomyelitis vaccine (inactivated poliovirus vaccine; RIVM, Bilthoven, the Netherlands). The Hib vaccines were given intramuscularly into the right buttock, and the diphtheria-pertussis-tetanus and in¬ activated poliovirus vaccines were administered intramuscularly into the left buttock. Healthy, mostly female young adults received intramuscular injections into the left arm of PRP-D (n 27), HbOC (n 19), C7p
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Calgary User on 05/25/2015
=
=
Table
.—Haemophilus influenzae Type (Hib) Vaccines Used in a Comparative Immunogenicity Trial Among Infants, Children, and Adults.
Lot No.
Vaccine PRP-D
5L294
HbOC
4102,4163* BrH-5-12, 1 lot
PRP-T
S-1890
Ine, Swiftwater, Pa Praxis Biologies Ine,
Rochester, NY Porter Anderson, Rochester, NY
6174
C7p
Manufacturer Connaught Laboratories
Institute Merieux, Lyons, France
Spacer
Amount of Hib Polysaccharide per Dose, µg
Polysaccharide Ratio
6 carbon
20
1.25
None
10
2.5
None
5
5.0
10
1.88
Type of
Saccharide Sized
Protein-to-
polysaccharidet 20-unit
oligosaccharide 7-unit
oligosaccharide Native
6 carbon
polysaccharide
*Lot4163
was used in infants and lots 5L294 and 4102 were used in adults and children. tThe molecular weight of the polysaccharide is heat sized to 200 to 2000 kd. tLot 61 74 was used in infants and lots BrH-5-12 and 6174 were used in adults and children.
( 18), or PRP-T ( 21). No other vaccinations were given at the same time. Children were immunized intramuscularly into the right buttock at 23 to 25 months of age with PRP-D (n 54), HbOC (n 56), or C7p (n 30). The children in the PRP-D group also received bivalent (groups A and C) meningococcal vaccine (Connaught Laboratories Ine, Swittwater, Pa) and/or 23-valent pneumococcal vaccine (Pneumovax, Merck Sharp & Dohme, West Point, Pa); these vaccines have been shown to have no effect on the response to a Hib conjugate vaccine or to Hib CPS vac¬ =
=
=
=
=
cine.22,24
Serum Samples Blood samples were obtained from infants before the first and second doses and 1 month after the second dose, ie, at 4, 6, and 7 months of age. Blood samples were obtained from children and adults before and 1 month after vaccination. The samples were preserved at -20°C until testing.
Follow-up of Adverse Reactions
The vaccinées were observed for at least 15 minutes after each vaccination. The vaccinées or their parents were given a special form to be completed 6, 12, 24, and 48 hours after vaccination. The rectal temperature, any systemic reaction, and description of local reactions at the injection site were recorded on this form.
Serologie Methods
Antibodies to the Hib PS were measured by a Farr-type rawith the use of a tyramine derivative of Hib dioimmunoassay25 PS prepared by Rachel Schneerson (National Institutes of Health, Bethesda, Md) for iodination. The reference serum was also re¬ ceived from Rachel Schneerson.
Statistical
Analysis
The geometric mean antibody concentrations (GMCs) were cal¬ culated with 0.06 mg/L as the lower and 320 mg/L as the higher limit of detection. Analysis of variance, Duncan's test at P .05 (both tests need log-transformed data), and 2 test were used for differences in the anti-Hib PS antibody concentrations at each =
sampling point.
RESULTS
Reactogenicity of the Hib Vaccines Irritability was the most common adverse effect among infants, reported in 41% to 60% of the vaccinées after the first dose and in 16% to 32% after the second dose. Fever was uncommon, detected in 2% to 5% of infants, regard¬ less of age at the time of vaccination. Local soreness was also uncommon. No significant differences were noted be¬ tween the vaccine groups regarding the frequency of re¬
actions. None of the adults or 2-year-old children had a fever after any of the vaccines. Local redness was reported in three children, and local soreness was reported in 14 chil-
dren, all of whom had received the PRP-D vaccine together with meningococcal vaccine and most of whom (n ll) had also received the Pneumovax vaccine. These reactions were probably due to the latter vaccine.22 =
Immunogenicity in Infants Infants were immunized at 4 and 6 months of age. The preimmunization anti-Hib PS concentrations were similar (0.07 to 0.09 mg/L) in each group (Fig 1); few children ac¬ tually had measurable antibody levels (Fig 2). Two months after the first dose, at the age of 6 months, the anti-Hib PS concentrations differed significantly in the four vaccine groups (P
