Comparison of diphtheria-tetanus-two component acellular pertussis vaccines in United States and Japanese infants at 2, 4, and 6 months of age.

OBJECTIVE: We compared the diphtheria and tetanus toxoids and bicomponent acellular pertussis vaccine (DTaP) responses in Japanese and United States infants. DESIGN: This was a double-blind, comparative study. SETTING: Private pediatric practices in Japan and the U.S. participated. SUBJECTS: One hundred eighty-nine healthy 2-month old infants were tested. INTERVENTIONS: Infants were immunized at 2, 4, and 6 months of age. The Japanese formulation (DTaP-J) contained 20 micrograms of pertussis toxin (PT) and 20 micrograms of filamentous hemagglutinin (FHA); the U.S. formulation (DTaP-US) contained 23.4 micrograms of each antigen. Parents used a standard form to record average adverse experiences. Serum was obtained before the first immunization, 2 months after the second immunization, and 1 month after the third immunization. MEASUREMENTS: Differences in DTaP-J and DTaP-US were evaluated in Japanese infants immunized subcutaneously (s.c.). Differences due to ethnicity and to route of administration were compared in U.S. infants immunized with DTaP-US s.c. or intramuscularly (i.m.). An indirect enzyme-linked immunosorbent assay was used to determine immunoglobulin G antibody responses to PT, FHA, and tetanus toxoid. Neutralizing antibody to PT was measured by a Chinese hamster ovary call assay. Diphtheria antitoxin was assayed by serum neutralization on VERO cells. RESULTS: Statistical differences (P < .05) in adverse events included less fatigue after immunization with DTaP-US compared with DTaP-J. Erythema of more than 2.5 cm was more frequent, but erythema less than 2.5 cm was less frequent in Japanese infants compared with U.S. infants. Fewer Japanese infants were febrile ( > 38 degrees C), tired, or irritable. Subcutaneous immunization resulted in a greater frequency of erythema and induration. The DTaP-US resulted in an equivalent response to PT and a greater response to FHA. More Japanese infants demonstrated at least a fourfold response over preimmunization antibody values to FHA. In U.S. infants, antibody responses to the contained pertussis antigens were equivalent after i.m. and s.c. administration. Compared with Japanese infants receiving DTaP-J s.c., U.S. infants receiving DTaP-US i.m. had equivalent responses to PT and a greater response to FHA. CONCLUSIONS: United States infants receiving an i.m. injection of a U.S. -produced bicomponent DTaP vaccine produced antibody responses to the contained pertussis antigens at least equal to those of Japanese infants receiving a similar bicomponent DTaP vaccine shown to be effective in older Japanese children.

Clinical survey of natural varicella compared with breakthrough varicella after immunization with live attenuated Oka/Merck varicella vaccine.

OBJECTIVE: To prospectively characterize varicella occurring in children previously immunized with a live attenuated varicella vaccine (breakthrough varicella) through daily observation by medical personnel and to compare it with natural varicella followed in the same manner. DESIGN: A blinded clinical survey. SETTING: Four pediatric practices (two private; two hospital-based). PARTICIPANTS: Healthy 12-month-old through 17-year-old children with chickenpox were studied; 92 had natural varicella and 58 had breakthrough varicella. SELECTION PROCEDURES AND INTERVENTIONS: Study personnel, unaware of vaccination status, documented the clinical characteristics of each patient in the office or at the patient's home each day from enrollment until the day after the total number of lesions increased less than 10%. A standard form documenting number and description of lesions, temperature, duration of illness, and associated clinical complaints was completed each day by the same study personnel. Acute and convalescent sera were obtained on breakthrough cases. MEASUREMENTS AND RESULTS: Antibody to varicella-zoster virus was measured by the glycoprotein-based enzyme-linked immunosorbent assay. Of those with sera available, 85% were serologically confirmed. Eighty-seven percent of enrollees had a known exposure to chickenpox, with at least two thirds of each group having a greater than 4-hour or a household exposure. The numbers of total and vesicular lesions were significantly higher in the natural varicella group, regardless of exposure status (P = .021 to < .001). The group with breakthrough varicella had a significantly lower incidence of fever (P < .001) and a significantly shorter duration of illness (P < .001). Other associated constitutional complaints and complications were not significantly different between groups. CONCLUSION: Varicella in vaccine recipients is clinically modified and significantly less severe than natural disease.

Simultaneous administration of measles-mumps-rubella vaccine with booster doses of diphtheria-tetanus-pertussis and poliovirus vaccines.

The safety and efficacy of simultaneous administration of measles-mumps-rubella (MMR), diphtheria-tetanus-pertussis (DTP), and trivalent oral poliovirus (OPV) vaccines in a test group of 405 children were compared with the safety and efficacy of sequential administration of the same vaccines in a control group of 410 children given MMR followed by booster doses of DTP and OPV 2 months later. The study was double blind and placebo controlled with respect to DTP and OPV. Seroconversion rates to measles, mumps, and rubella exceeded 96% in both groups. Geometric mean titers to measles (P = .05) and rubella (P = .004) were higher in the test group, and titers of antibodies to the other seven antigens were similar in both groups. Clinical reaction data were analyzed in 248 of 405 test children and 249 of 410 control children. The rates of serious vaccine-associated reactions were low and similar in the two groups. Some minor side effects were reported more frequently in the test group, but these differences were judged to be related to study design rather than to differences in the safety of the two vaccine schedules. The results indicate that the safety and serologic efficacy of administering MMR simultaneously with reinforcing doses of DTP and OPV in the second year of life is equivalent to the safety and efficacy observed after administering these antigens separately.

Comparison of a three-component acellular pertussis vaccine with a whole-cell pertussis vaccine in 15- through 20-month-old infants.

OBJECTIVE: To compare the immunogenicity and reactogenicity of a diphtheria and tetanus toxoids and three-component acellular pertussis vaccine (DTaP) with a diphtheria and tetanus toxoids and whole-cell pertussis vaccine (DTwP) when administered as a booster dose to infants 15 through 20 months of age. DESIGN: Randomized, double-blind, comparative study. SETTING: Three pediatric practices (two private; one hospital-based). PARTICIPANTS: One hundred and sixty-five healthy 15- through 20-month old infants. SELECTION PROCEDURES AND INTERVENTIONS: Infants were randomly assigned in a 2:1 ratio to receive vaccine from a single lot of DTaP or from commercially available DTwP. DTaP contained 25 micrograms of pertussis toxoid, 25 micrograms of filamentous hemagglutinin, 8 micrograms of pertactin (69-kilodalton outer membrane protein), 25 flocculating units of diphtheria toxoid, and 10 flocculating units of tetanus toxoid per 0.5-mL dose. DTwP contained one half the concentrations of diphtheria and tetanus toxoids compared with DTaP and a pertussis component with a potency of 4 U/0.5-mL dose. Serum samples were obtained on the day of immunization and 4 weeks later. Adverse reactions were recorded by parents for 7 days after immunization. An interval history was obtained 4 weeks after immunization. MEASUREMENTS AND RESULTS: IgG antibody to pertussis toxoid, filamentous hemagglutinin, pertactin, diphtheria toxoid, and tetanus toxoid was measured by an indirect enzyme-linked immunosorbent assay (ELISA) method. One month after immunization, the geometric mean antibody levels after DTaP compared with DTwP were: pertussis toxoid, 70.6 vs 28 ELISA U/mL (P = .003); filamentous hemagglutinin, 183.4 vs 43 ELISA U/mL (P < .001); pertactin, 216 vs 49.9 ELISA U/mL (P < .001); diphtheria, 14.1 vs 14.9 IU/mL (P = .74); and tetanus, 11.9 vs 14.8 IU/mL (P = .089). After immunization with DTaP, most local and systemic adverse experiences were significantly fewer compared with DTwP (P < .05). CONCLUSIONS: This three-component DTaP vaccine demonstrates significantly greater immune responses to pertussis toxoid, filamentous hemagglutinin, and pertactin, equivalent immune responses to diphtheria and tetanus toxoids, and significantly less reactogenicity compared with a licensed DTwP.

Comparison of antigenuria after immunization with three Haemophilus influenzae type b conjugate vaccines.

The incidence of antigenuria was documented after vaccination of 75 children 15 to 60 months of age with one of three Haemophilus influenzae type b conjugate vaccines, PRP-D (ProHIBiT), PRP-T and HbOC (HibTITER). Unconcentrated and concentrated urine was tested on the first, third, fifth and seventh days after vaccination. Antigenuria occurred on Day 1 in 100% of PRP-D, 43% of PRP-T and 12% of HbOC recipients. The percentages of children excreting antigen on Day 3 were 95, 17 and 8%; on Day 5 they were 36, 4 and 12%; and on Day 7 they were 14, 0 and 18% for PRP-D, PRP-T and HbOC, respectively. The difference in the occurrence of antigenuria resulting from each vaccine was statistically significant on Day 1 and for PRP-D compared with PRP-T or HbOC on Day 3. It is important for clinicians to be aware of the frequency with which antigenuria occurs after these vaccines so that appropriate therapeutic decisions can be made.

Comparison of a three-component acellular pertussis vaccine with a whole-cell pertussis vaccine in 4- through 6-year-old children. Elmwood Pediatric Associates, Pennridge Pediatric Associates.

OBJECTIVE: To compare the safety and immunogenicity of a three-component acellular pertussis (DTaP) vaccine containing pertussis toxin (PT), filamentous hemagglutinin (FHA), and pertactin with whole-cell pertussis (DTwP) vaccine in 4- through 6-year-old children. PARTICIPANTS: One hundred seventy-two healthy 4- through 6-year-old children previously immunized with the DTwP vaccine at or near 2, 4, 6, and 18 months of age. INTERVENTIONS: Prevaccination serum samples were obtained on all study participants. One hundred twelve children received 0.5 mL of the DTaP vaccine intramuscularly. Fifty-three children received 0.5 mL of a commercially available DTwP vaccine intramuscularly. Approximately 30 days following vaccination, additional serum samples were obtained. MEASUREMENTS: Parents monitored adverse reactions for 7 days following immunization. Significantly fewer children in the DTaP group reported temperatures of greater than 38.1 degrees C and an area of redness of more than 10 mm and moderate-to-severe pain at the injection site. RESULTS: Antibody responses to PT, FHA, pertactin, and diphtheria and tetanus toxoids were measured by enzyme-linked immunosorbent assay. Among subjects who were seronegative prior to vaccination, response was defined as the detection of antibody levels following vaccination; among children with detectable antibody levels prior to vaccination, in terms of the rise in antibody titers. Data using a twofold and a fourfold rise in antibody titers as criteria to define response were evaluated. Children in the DTaP group had significantly greater increases in geometric mean titers of antibodies against PT, FHA, and pertactin. Over 90% of the DTaP group responded to PT, FHA, and pertactin according to the criteria of both the twofold and the fourfold rise in antibody titers. Significantly fewer of the DTwP group responded to PT, FHA, and pertactin with at least a fourfold rise in antibody titers. When analyzing subjects with at least a twofold increase in antibody titers, a statistically significant difference remained in regard to anti-FHA antibodies. All study subjects had protective antibody titers against diphtheria and tetanus toxoids following vaccination. The geometric mean titer of antibodies against tetanus was significantly greater in the DTwP group than in the DTaP group. CONCLUSION: The three-component DTaP vaccine administered as a booster immunization in 4-through 6-year-old children produced less fever and less redness and pain at the injection site than the DTwP vaccine and was as immunogenic as the DTaP vaccine.

Kinetics of antibody response to Haemophilus influenzae type b vaccines. Pennridge Pediatric Associates.

Serum antibodies to the capsular polysaccharide of Haemophilus influenzae type b (Hib) are effective in preventing or ameliorating invasive disease caused by this human pathogen. Polysaccharide and conjugate (saccharide covalently linked to protein carrier) vaccines have been developed which stimulate the production of such antibodies. The polysaccharide-specific antibody concentrations in the sera of vaccine-naïve adults and toddlers on days 1, 3, 7, 14 and 28 following immunisation with one dose of the Hib polysaccharide vaccine (PRP, polyribosylribitol phosphate) or an oligosaccharide-CRM197 conjugate vaccine (HbOC, HibTITER) were determined. Antibody responses occurred within 7 days of immunisation with the maximum response usually occurring 14 days post-immunisation, irrespective of vaccine or subject age. In this small study, a significant transient decline in pre-existing antibodies was observed only in the groups receiving the polysaccharide vaccine and not in the groups receiving HbOC vaccine. Because of the small magnitude of antigen-specific antibody decline and its transient nature, it is unlikely that this observation has clinical significance.

Dose titration study of live attenuated varicella vaccine in healthy children. Pennridge Pediatric Associates.

To approximate the effect of prolonged storage on safety and immunogenicity, healthy children were given a single dose of the currently marketed live attenuated varicella vaccine (3625 pfu) or of a partially heat-inactivated vaccine (1125 or 439 pfu). The 3 doses had similar antigen content (attenuated plus inactive virus particles). The vaccine was well tolerated. No significant differences in adverse reactions were observed. Although the seroconversion rates were excellent at each dose (> or = 98%), the higher doses resulted in significantly greater geometric mean antibody titers at 6 weeks (10.5 and 10.6 ELISA U/mL) compared with the 439 pfu dose (5.7 ELISA U/mL), P < or = .01. One year after immunization, differences in antibodies were similar to the 6-week postimmunization results. Results indicate that until the date of expiry, the vaccine's immunogenicity will be preserved and there will be no clinically important changes in type or frequency of adverse events.

Immunogenicity of four Haemophilus influenzae type b conjugate vaccines in 17- to 19-month-old children.

OBJECTIVE: To compare the immunogenicity of four Haemophilus influenzae type b (Hib) conjugate vaccines in different populations of 17- to 19-month-old children in the United States. DESIGN: Four immunogenicity trials with sera were assayed in one laboratory. Trials 1 and 2 each compared one vaccine in two regions, and trials 3 and 4 were randomized comparisons of multiple vaccines within a region. SUBJECTS: A convenience sample of 313 healthy children recruited from pediatric practices in Minneapolis, Minn., Dallas and Houston, Tex., and Sellersville, Pa. MEASUREMENTS AND RESULTS: Children with prevaccination antibody greater than 0.15 microgram/ml showed higher antibody responses to vaccination than children with less than or equal to 0.15 microgram/ml (p less than 0.001). Among the former, there were no significant differences in antibody response to vaccination with the different conjugates within any of the trials. Among children with less than or equal to 0.15 microgram/ml of antibody before vaccination, there were no significant differences in the geometric mean antibody responses of children in trial 1 vaccinated with polyribosylribitol phosphate-diphtheria toxoid (PRP-D) in Dallas or in Minneapolis, or of children in trial 3 in Dallas randomly assigned to receive Hib oligosaccharide-CRM197 (HbOC) or PRP-D. In contrast, in trial 2, children given PRP-tetanus toxoid (PRP-T) in Pennsylvania had a significantly higher geometric mean antibody response than children given PRP-T in Houston (13.5 vs 3.0 micrograms/ml; p = 0.005). In trial 4 in Minneapolis, the geometric mean antibody response was highest in children randomly assigned to receive PRP-outer membrane protein (OMP) (9.3 micrograms/ml), followed by PRP-D (5.0 micrograms/ml) and HbOC (2.3 micrograms/ml) (PRP-OMP vs HbOC; p = 0.005). In all four trials, IgG1 responses predominated compared with IgG2 responses. CONCLUSIONS: All four conjugate vaccines are immunogenic in children 17 to 19 months of age. However, the magnitude of the anticapsular antibody response varied by vaccine type, the level of antibody in prevaccination sera, and geographic location.

Simultaneous administration of a diphtheria and tetanus toxoids and acellular pertussis vaccine with measles-mumps-rubella and oral poliovirus vaccines.

OBJECTIVE: To compare the safety and immunogenicity of Lederle Laboratories' (Pearl River, NY) diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine with diphtheria and tetanus toxoids and whole-cell pertussis (DTwP) vaccine when administered simultaneously with measles-mumps-rubella (MMR) vaccine and trivalent oral poliovirus (OPV) vaccine at 15 to 16 months of age. DESIGN: Randomized and double-blind. SETTING: Two general pediatric practices. PARTICIPANTS: Ninety-seven infants, aged 15 to 16 months, who had received three previous DTwP immunizations. SELECTION PROCEDURES AND INTERVENTIONS: Healthy children received the DTaP or DTwP vaccine. Infants received the MMR vaccine at a separate site and the OPV vaccine concurrently. Blood was obtained on day 0 and at 6 weeks. Adverse events were recorded by parents at specified times after immunization. MEASUREMENTS/RESULTS: Within 3 days of immunization, DTaP vaccine recipients had less fever, drowsiness, and irritability (P = .01, .04, .01, respectively). They also experienced less tenderness, erythema, and induration (.001, .001, and .002, respectively). There was no difference in the frequency of adverse reactions 6 to 14 days after immunization. Enzyme-linked immunosorbent assays were used to determine all antibody values. Antibody responses to filamentous hemagglutinin and pertussis toxoid were significantly greater in the DTaP group (P = .0001 and .02, respectively). Immune responses to the other measured antigens were similar. CONCLUSIONS: Simultaneous administration of the Lederle DTaP with MMR and OPV vaccines did not interfere with antibody response to pertussis antigens measured or measles, mumps, or rubella viruses and was associated with fewer local and systemic adverse events during the first 3 days following immunization when compared with the simultaneous administration of the DTwP, OPV, and MMR vaccines. We conclude that the DTaP vaccine can be administered at 15 months of age concurrently with the MMR and OPV vaccines.

Response of 7- to 15-month-old infants to sequential immunization with Haemophilus influenzae type b-CRM197 conjugate and polysaccharide vaccines.

OBJECTIVE: To evaluate the immunologic potential of infants 7 to 15 months of age to respond to Haemophilus influenzae type b polysaccharide vaccine following immunization with H influenzae b oligosaccharide-CRM197 conjugate vaccine. STUDY DESIGN: One hundred seventy-one infants, aged 7 to 15 months, were consecutively and alternatively assigned to one of three immunization protocols. Group 1 (n = 71) received three doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine, group 2 (n = 47) received two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine followed by one dose of H influenzae type b polysaccharide vaccine, and group 3 received one dose of H influenzae b oligosaccharide-CRM197 conjugate vaccine followed by two doses of H influenzae type b polysaccharide vaccine. Immunizations were given on day 0 and at 2 months and 6 months. Anti-H influenzae type b polysaccharide antibody levels were measured on day 0 and 2, 3, 6, 7, and 12 months after the study began. RESULTS: Haemophilus influenzae type b polysaccharide vaccine given as a second dose stimulated an antibody rise but did so less effectively than H influenzae b oligosaccharide-CRM197 conjugate vaccine. Two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine were highly immunogenic; geometric means were 31 and 35 micrograms/mL in the 7- to 11-month and 12- to 15-month age groups, respectively. Following two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine, both immunization protocols resulted in (1) equally high geometric mean antibody levels 1 month after immunization and (2) similar geometric mean antibody levels 6 months after immunization. CONCLUSIONS: Haemophilus influenzae b oligosaccharide-CRM197 conjugate vaccine induces antibody levels that would be expected to protect infants from initial invasion and primes the immune system for an anamnestic response. Our data indicate that if a booster immunization is needed, H influenzae type b polysaccharide vaccine could be an alternative to H influenzae b oligosaccharide-CRM197 conjugate vaccine.

Immunogenicity of Haemophilus influenzae type b polysaccharide-tetanus toxoid conjugate vaccine in infants.

OBJECTIVE: To compare the safety and immunogenicity of three investigational lots of Haemophilus influenzae type b polysaccharide-tetanus toxoid (PRP-T) conjugate vaccine in infants. DESIGN: A multicenter, randomized immunogenicity trial. Infants were vaccinated at 2, 4, and 6 months of age with one of three lots of PRP-T. A control group received H influenzae type b oligomers conjugated to CRM197 (HbOC). Serum was obtained before each injection and 1 month after the third dose, and assayed blindly for antibody in one laboratory. SUBJECTS: Four hundred eighty-four infants from private pediatric practices located in five geographic areas. MEASUREMENTS AND RESULTS: There were no significant differences in the number of adverse events reported for infants receiving PRP-T or HbOC, and the rates did not exceed those observed previously in infants given diphtheria-tetanus-pertussis vaccine alone. Total serum anti-PRP antibody responses were analyzed in 336 infants who met strict inclusion criteria. After one, two, or three doses, the respective antibody responses to each of the three lots of PRP-T and to HbOC vaccine were similar. The only exception was one lot of PRP-T, which after one or two injections elicited significantly higher geometric mean antibody responses than the other two lots or the HbOC vaccine. After a third injection, there were no significant lot differences. Combining the data from the different lots, there were no significant differences in the geometric mean antibody concentration after three doses of PRP-T or HbOC (8.3 vs 7.7 micrograms/mL), and 95% and 91%, respectively, of infants had greater than 1.0 microgram/mL of antibody. There were no significant differences in the magnitudes of the respective IgG1-, IgG2-, and IgM-specific antibody concentrations between infants given PRP-T or HbOC. CONCLUSIONS: The three investigational lots of PRP-T tested were safe and were as immunogenic as or more so than the licensed HbOC conjugate vaccine.

Clinical reactions and immunogenicity of the BIKEN acellular diphtheria and tetanus toxoids and pertussis vaccine in 4- through 6-year-old US children.

OBJECTIVE--To compare the immunogenicity and reactogenicity of a two-component acellular pertussis vaccine with a whole-cell diphtheria and tetanus toxoids and pertussis vaccine (W-DTP) when administered as a booster to children 4 through 6 years of age. DESIGN--This was a randomized, double-blind study. SETTING--Children in this study were from three general pediatric practices (two were private, one was university-affiliated). PARTICIPANTS--Three hundred and sixteen 4- through 6-year-old children who had received four previous W-DTP immunizations at the recommended times were studied. SELECTION PROCEDURES AND INTERVENTIONS--Children were randomly assigned in a 1:3 ratio to receive either W-DTP or one of three lots of acellular diphtheria and tetanus toxoids and pertussis vaccine (A-DTP). The A-DTPs contained 3.75 micrograms each of lymphocytosis promoting factor and filamentous hemagglutinin protein nitrogen per 0.5 mL and the same concentrations of diphtheria and tetanus toxoids as W-DTP. Serum samples were obtained on the day of immunization and 4 to 6 weeks later. Adverse reactions were recorded by parents at 6, 24, 48, and 72 hours. MEASUREMENTS AND RESULTS--An indirect enzyme-linked immunosorbent assay (ELISA) method determined IgG antibody response to lymphocytosis promoting factor, filamentous hemagglutinin, and tetanus toxoid; a CHO cell assay measured neutralizing antibodies to pertussis toxin; and serum neutralization on VERO cells assayed diphtheria antitoxin. One month after booster doses were administered, the geometric mean antibody levels for A-DTP vs W-DTP were IgG filamentous hemagglutinin, 362 vs 104 ELISA U/mL; IgG lymphocytosis promoting factor, 408 vs 81 ELISA U/mL; CHO cell, 210 vs 107; diphtheria, 21.7 vs 12.1 U/mL; and tetanus, 2.86 vs 2.04 Eq/mL. Following immunization with A-DTP, local and systemic adverse experiences were 30% to 50% and 20% to 30% fewer, respectively, as compared with W-DTP. CONCLUSIONS--The BIKEN A-DTP vaccine used in this study demonstrates enhanced immunogenicity to lymphocytosis promoting factor, filamentous hemagglutinin, and other measured antigens and less reactogenicity compared with licensed W-DTP [corrected].

Reactogenicity and immunogenicity of a three-component acellular pertussis vaccine administered as the primary series to 2, 4 and 6 month old infants in the United States.

Five hundred and fifty-seven infants received either an acellular pertussis (DTaP) vaccine containing pertussis toxoid (PT), filamentous hemagglutinin (FHA) and pertactin (PRN) or one of two commercially available whole-cell pertussis (DTP) vaccines at 2, 4 and 6 months. One month after the third immunization, IgG antibody values to pertussis toxoid, filamentous hemagglutinin and PRN were significantly greater following DTaP than either DTP (P < 0.05). When reactions within 48 h after all three doses of vaccine were combined, fever 101 degrees, > or = moderate fussiness, > or = moderate pain, swelling 10 mm, and erythema 10 mm occurred less often after DTaP compared with DTP-Connaught (P < 0.001). The same adverse events were also less after DTaP compared with DTP-Lederle (P < 0.05), except for erythema 10 mm. This three-component DTaP vaccine produced fewer adverse events and greater antibody values to PT, FHA and PRN in comparison with either licensed DTP vaccine when given as the primary series.

An acellular pertussis vaccine in healthy adults: safety and immunogenicity. Pennridge Pediatric Associates.

Recent data indicate that Bordetella pertussis can be an important cause of illness in adolescents and adults. In a randomized observer- and subject-blinded study, adults (> or = 18 years of age) received an acellular pertussis (aP) vaccine containing genetically inactivated pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN), or a saline placebo, and were monitored for safety and immunogenicity. IgG antibodies to PT, FHA, and PRN were measured by enzyme-linked immunosorbent assay (ELISA) and PT neutralization by a Chinese hamster ovary (CHO) cell assay. Local reactions, more common in the aP group, were mild and transient. One month after immunization, geometric mean ELISA antibody concentrations for the aP and placebo groups, respectively, were: anti-PT, 463 and 7.6; anti-FHA, 417 and 18; and anti-PRN, 855 and 14. The anti-PT neutralization titers for the aP and placebo groups were 1:3439 and 1:58 respectively. This aP vaccine is a safe and immunogenic candidate booster vaccine against pertussis for adults.