Sustained efficacy and immunogenicity of the human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine: analysis of a randomised placebo-controlled trial up to 6.4 years.

BACKGROUND: Prophylactic human papillomavirus (HPV) vaccines have to provide sustained protection. We assessed efficacy, immunogenicity, and safety of the HPV-16/18 AS04-adjuvanted vaccine up to 6.4 years. METHODS: Women aged 15-25 years, with normal cervical cytology, who were HPV-16/18 seronegative and oncogenic HPV DNA-negative (14 types) at screening participated in a double-blind, randomised, placebo-controlled initial study (n=1113; 560 vaccine group vs 553 placebo group) and follow-up study (n=776; 393 vs 383). 27 sites in three countries participated in the follow-up study. Cervical samples were tested every 6 months for HPV DNA. Management of abnormal cytologies was prespecified, and HPV-16/18 antibody titres were assessed. The primary objective was to assess long-term vaccine efficacy in the prevention of incident cervical infection with HPV 16 or HPV 18, or both. We report the analyses up to 6.4 years of this follow-up study and combined with the initial study. For the primary endpoint, the efficacy analysis was done in the according-to-protocol (ATP) cohort; the analysis of cervical intraepithelial neoplasia grade 2 and above (CIN2+) was done in the total vaccinated cohort (TVC). The study is registered with ClinicalTrials.gov, number NCT00120848. FINDINGS: For the combined analysis of the initial and follow-up studies, the ATP efficacy cohort included 465 women in the vaccine group and 454 in the placebo group; the TVC included 560 women in the vaccine group and 553 in the placebo group. Vaccine efficacy against incident infection with HPV 16/18 was 95.3% (95% CI 87.4-98.7) and against 12-month persistent infection was 100% (81.8-100). Vaccine efficacy against CIN2+ was 100% (51.3-100) for lesions associated with HPV-16/18 and 71.9% (20.6-91.9) for lesions independent of HPV DNA. Antibody concentrations by ELISA remained 12-fold or more higher than after natural infection (both antigens). Safety outcomes were similar between groups: during the follow-up study, 30 (8%) participants reported a serious adverse event in the vaccine group versus 37 (10%) in the placebo group. None was judged related or possibly related to vaccination, and no deaths occurred. INTERPRETATION: Our findings show excellent long-term efficacy, high and sustained immunogenicity, and favourable safety of the HPV-16/18 AS04-adjuvanted vaccine up to 6.4 years. FUNDING: GlaxoSmithKline Biologicals (Belgium).

Immunogenicity of subcutaneous versus intramuscular Oka/Merck varicella vaccination in healthy children.

To compare the immunogenicity and safety of varicella vaccine by either subcutaneous or intramuscular injection, 166 healthy children aged 12 months to 10 years old who had no prior history of varicella were enrolled from two pediatric practices and randomly assigned to receive 0.5 mL of a single lot of varicella vaccine. Sera from the day of and 6 weeks postvaccination were tested for varicella antibody by gpELISA. Parents recorded clinical events occurring in the 6 weeks following vaccination. In the 132 evaluable children, the mean prevaccination titer was 0.3 gpELISA units for both groups. Sixty-three (97%) of the 65 receiving varicella vaccine by the subcutaneous route seroconverted compared with 67 (100%) of 67 immunized intramuscularly. Postvaccination geometric mean titer in the subcutaneous group was 6.9 +/- 7.0 gpELISA units and did not differ significantly from the geometric mean titer of 10.5 +/- 4.4 in the intramuscular group. Varicella vaccine was generally well tolerated by either route; 21% of both groups complained of reactions at the injection site and 7% had a varicella-like rash. Although varicella vaccine is recommended to be given subcutaneously, the results of this study indicate that inadvertent intramuscular administration of varicella vaccine is not reason for revaccination.

Acellular pertussis vaccination of 2-month-old infants in the United States.

This is the first study in children from the United States that evaluates the immunogenicity of and adverse reactions to the Connaught/Biken two-component acellular pertussis vaccine compared with whole-cell pertussis vaccine when given as a primary immunization series at 2, 4, and 6 months of age. Three hundred eighty infants were studied; 285 received acellular diphtheria-tetanus toxoids-pertussis (DTP (ADTP)) and 95 received whole-cell DTP (WDTP). Following the third dose, ADTP vaccination produced higher antibody responses than WDTP to lymphocytosis-promoting factor (enzyme-linked immunosorbent assay IgG geometric mean titer (GMT) = 131 vs 9 and Chinese hamster ovary cell assay GMT = 273 vs 16) and to filamentous hemagglutinin (IgG GMT = 73 vs 10) (all P less than .0001). Agglutinin responses were higher in WDTP compared with ADTP recipients (GMT = 50 vs 37; P = .02). Local reactions were fewer for all three doses following ADTP vaccination. Fever, irritability, drowsiness, anorexia, vomiting, and unusual crying all occurred less frequently in ADTP compared with WDTP recipients for one or more of the three doses. We conclude that this two-component ADTP vaccine when given as a primary series produces greater immunogenicity and fewer adverse effects than the currently licensed WDTP vaccine.

Safety and immunogenicity of a combined diphtheria, tetanus, pertussis and Haemophilus influenzae type b vaccine in young infants.

OBJECTIVE: To study the safety and immunogenicity of a combined diphtheria-tetanus-pertussis (DTP)-Haemophilus influenzae type b (HbOC) vaccine (TETRAMUNE) in infants as young as 2 months of age as compared to separate administration of DTP and HbOC. METHODS: Two-month-old infants were randomized to receive three doses 2 months apart of either DTP-HbOC as a single 0.5-mL injection or to receive 0.5 mL of DTP and HbOC concurrently in separate legs. Local and systemic adverse reactions were monitored within 72 hours of each immunization, and immunogenicity of each of the four vaccine components was measured. RESULTS: The incidence of both local and systemic adverse events following the tetravalent vaccine was similar to the incidence following separate vaccine administration. After three doses of vaccine, the response to each of the vaccine components was higher in the combined vaccine when compared to separate administration. In the case of the Haemophilus influenzae type b component, this enhancement was also seen after two doses. The response to the combined vaccine was consistent among the three lots tested as was the enhancement over separate administration. CONCLUSIONS: The DTP-HbOC vaccine was safe and immunogenic in young infants and was generally more immunogenic than separate vaccination with DTP and HbOC. The use of such a combined vaccine reduces the number of injections given to young infants by half and is an important step toward improving vaccine delivery.

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.

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.

Amoxicillin or myringotomy or both for acute otitis media: results of a randomized clinical trial.

A total of 536 infants and children with acute otitis media were randomly assigned to one of six consistent year-long regimens involving the treatment of nonsevere episodes with either amoxicillin or placebo, and severe episodes with either amoxicillin, amoxicillin and myringotomy, or, in children aged 2 years or older, placebo and myringotomy. Nonsevere episodes had more favorable outcomes in subjects assigned to treatment with amoxicillin than with placebo, as measured by the proportions that resulted in initial treatment failure (3.9% vs 7.7%, P = .009) and the proportions in which middle-ear effusion was present at 2 and 6 weeks after onset (46.9% vs 62.5%, P less than .001; and 45.9% vs 51.5%, P = .09, respectively). In subjects whose entry episode was non-severe, those assigned to amoxicillin treatment had less average time with effusion during the succeeding year than those assigned to placebo treatment (36.0% vs 44.4%, P = .004), but recurrence rates of acute otitis media in the two groups were similar. In the 2-year-and-older age group, severe episodes resulted in more initial treatment failures in subjects assigned to receive myringotomy alone than in subjects assigned to receive amoxicillin with, or without, myringotomy (23.5% vs 3.1% vs 4.1%, P = .006). In the study population as a whole, severe episodes in subjects assigned to receive amoxicillin alone, and amoxicillin with myringotomy, had comparable outcomes. It is concluded that children with acute otitis media should routinely be treated with amoxicillin (or an equivalent antimicrobial drug). The data provide no support for the routine use of myringotomy either alone or adjunctively.

Comparative study of sultamicillin and amoxicillin-clavulanate: treatment of acute otitis media.

Sultamicillin is a mutual prodrug of ampicillin and sulbactam that is chemically linked by a diester bond. This investigational agent has beta-lactamase-inhibiting activity by virtue of sulbactam, a novel beta-lactamase inhibitor. A double blind randomized study was conducted to evaluate the safety, efficacy and tolerance of sultamicillin for treatment of acute otitis media compared with amoxicillin-clavulanate. A total of 144 subjects were included (96 randomly assigned to the sultamicillin and 48 to the amoxicillin-clavulanate groups). No safety concerns for sultamicillin were identified during the study. The clinical efficacy in effusion clearance between the two groups was found not to be statistically different at 10 days (P = 0.23) and 30 days (P = 0.72). Similar rates of side effects, primarily gastrointestinal, were reported in both study groups. Sultamicillin may be an alternative for the treatment of acute otitis media when persistence and recurrence of disease become an issue.

Safety and immunogenicity of four doses of Neisseria meningitidis group C vaccine conjugated to CRM197 in United States infants.

BACKGROUND: Following widespread use of conjugate pneumococcal vaccine, Neisseria meningitidis likely will become the leading cause of bacterial sepsis and meningitis in US children. This report describes the safety and immunogenicity in US children of four consecutive doses of a meningococcal group C vaccine conjugated to CRM197 via reductive amination (MnCC). METHODS: One hundred six healthy 2-month-old infants received MnCC at 2, 4 and 6 months of age in a randomized, controlled double blind study; children in the other treatment arm were given a 7-valent conjugate pneumococcal vaccine. Parents reenrolled 64 of these children at 12 to 15 months to receive a fourth dose of MnCC. Routine childhood vaccines, including DTP, were coadministered. Temperatures and symptoms were recorded for 3 days after each immunization. Serum enzyme-linked immunosorbent assay IgG and bactericidal antibodies were measured prevaccination and before and 1 month after Doses 3 and 4. RESULTS: Moderate to severe local reactions, defined as erythema or induration > or =2.4 cm or pain that interfered with limb movement was reported after 0 to 3.2% of MnCC injections, depending on the reaction and dose. Fever occurred in 23 to 37% of children, but the contribution of MnCC to the febrile reactions is unknown. Geometric mean concentrations of IgG antibody to group C meningococcal polysaccharide were 3.72 microg/ml after Dose 3 and 8.03 microg/ml after the booster. Geometric mean functional serum bactericidal antibody titers after Doses 3 and 4 were 1:463 and 1:2341, respectively. One hundred percent of children had a serum bactericidal antibody titer of > or =1:64 after three doses and > or = 1:128 after the booster. CONCLUSIONS: The MnCC vaccine had an acceptable safety profile and generated high titers of bactericidal antibody in immunized US infants and toddlers. It appears to be an attractive candidate vaccine for the prevention of serogroup C meningococcal disease in young children.

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.

A comparative study of amoxicillin-clavulanate and amoxicillin. Treatment of otitis media with effusion.

A double-blind randomized clinical trial was conducted at two sites comparing amoxicillin-clavulanate potassium (Augmentin) and amoxicillin trihydrate for the treatment of otitis media with effusion ("secretory otitis media"). One hundred eight subjects were randomly assigned to receive a ten-day course of either drug regimen. Clinical response was assessed at ten days and four weeks after entry. For those without middle ear effusion at four weeks, recurrence rates were measured at 8, 12, and 16 weeks after entry. At ten days following entry, 29 (51.8%) of 56 subjects in the amoxicillin-clavulanate-treated group were effusion free compared with 16 (32.0%) of 50 subjects in the amoxicillin-treated group (P = .06). At four weeks following entry, 26 (50.0%) of 50 subjects in the amoxicillin-clavulanate-treated group were effusion free compared with 23 (51.1%) of 45 subjects in the group given amoxicillin. By the 16-week visit, eight (36.4%) of 22 subjects in the amoxicillin-clavulanate-treated group who were effusion free at four weeks had recurrence of effusion, compared with 12 (63.2%) of 19 subjects in the amoxicillin-treated group. This study suggests that there was a favorable clinical response immediately following treatment in the amoxicillin-clavulanate--treated subjects as compared with those treated with amoxicillin, but this benefit was not sustained at the four-week end point.

Growth of newborn, term infants fed soy formulas for 1 year.

Few studies have measured long-term growth in infants fed soy protein-based formulas. The effect of nucleotide (NT) supplementation of soy protein-based infant formulas on growth is unknown. Growth was therefore evaluated in healthy term infants fed a soy protein-based formula (SOY; n = 73), SOY with added NT (72 mg added NT/L) at human milk (HM) levels (SOYN, n = 73), or mixed feeding (MF, n = 67) in a randomized, masked, parallel 1-year feeding study. The MF group (a nonrandomized reference group) was fed HM exclusively from birth to 2 months of age followed by HM and/or a standard milk-based formula (Similac with Iron with no supplemental NTs) to 1 year of age. Results indicated that growth (weight, length, and head circumference) was normal and comparable among the three groups. All three groups had similar plasma albumin (at 2 months of age) and hemoglobin levels (at 12 months of age). Thus, this study demonstrated similar growth in the first year of life among infants fed MF feeding or soy formula with or without supplemental NTs.

Pediatric counseling and subsequent use of smoke detectors.

Effects of a brief educational and purchase program concerning home fires and smoke detectors by two pediatricians were compared to "routine" counseling without such a program using two groups each of 120 patients of well children. Inspection performed four to six weeks after the office visits showed that of 55 experimental group parents without detectors prior to the program, 26 purchased and 19 installed them correctly. No control group parents did so.

Sultamicillin (ampicillin-sulbactam) in the treatment of acute otitis media in children.

Sultamicillin, a dimer of ampicillin and a beta-lactamase-inhibiting agent, sulbactam, was given in oral form to 50 infants and children with acute otitis media. Tympanocentesis was performed on entry into the trial. Beta-lactamase-positive Haemophilus influenzae or Branhamella catarrhalis was isolated from 14 of 73 (19.2%) middle ear effusions in 9 children. Relief of symptoms (fever/otalgia) occurred in all children who completed therapy. However, in 8 children (16%), the antimicrobial agent was discontinued due to presumed adverse side effects (primarily gastrointestinal); vomiting which began prior to entry was noted in another subject who was withdrawn. An additional 14 children completed the course of treatment despite having diarrhea. Of the 41 children who completed drug therapy, 11 (26.8%) were effusion-free after 10 days, and 22 of 33 (66.7%) evaluable children were effusion-free after 6 weeks. Sultamicillin is a novel therapeutic approach to beta-lactamase-producing bacteria. In its oral form, however, diarrhea is a troublesome side effect.

Duration of effusion after antibiotic treatment for acute otitis media: comparison of cefaclor and amoxicillin.

A double-blind randomized clinical trial was conducted at two sites comparing cefaclor and amoxicillin for the treatment of acute otitis media with effusion in 214 children (293 ears). Each child underwent unilateral or bilateral tympanocentesis and then was randomly assigned to receive a 14-day course of either amoxicillin or cefaclor. The symptomatic clinical response was the same for the two antibiotics, with four children considered "treatment failures" in each antibiotic treatment group. By 14 days after entry into the study 59 of 106 children (55.7%) in the cefaclor group had ears that were effusion-free as compared to 40 of 97 children (41.2%) in the amoxicillin group (P = 0.05). When considering all children with effusion-free ears as well as those "improved" from their original status (those with bilateral middle ear effusions at entry but only unilateral after treatment), 68 of 106 children (64.2%) receiving cefaclor were effusion-free or "improved," compared to 43 of 97 children (44.3%) receiving amoxicillin (P = 0.01). However, by 42 days after entry the percentage of children whose ears were without effusion or "improved" was equal in both treatment groups (68.9% in the cefaclor group and 67.5% in the amoxicillin group). The reasons for the differences observed at 14 days after entry are not readily apparent.

Comparison of an acellular pertussis-component diphtheria-tetanus-pertussis (DTP) vaccine with a whole-cell pertussis-component DTP vaccine in 17- to 24-month-old children, with measurement of 69-kilodalton outer membrane protein antibody.

Healthy 17- to 24-month-old children, previously immunized with three doses of whole-cell diphtheria-tetanus-pertussis (DTP) vaccine, were enrolled in a multi-center double-blind, randomized study comparing a DTP vaccine with an acellular pertussis-component (APDT) and a conventional whole-cell pertussis-component DTP vaccine. Thirty-eight children received APDT vaccine, and 37 children received DTP vaccine. APDT vaccine recipients had significantly less local pain and warmth than DTP vaccine recipients. Antibody responses to lymphocytosis-promoting factor were similar in the two groups. The APDT vaccine recipients had a higher IgG antibody response to filamentous hemagglutinin than the DTP vaccinees had. Equivalent agglutinin responses were seen in the two groups. The APDT vaccine recipients had a significantly better antibody re-enzyme-linked immunosorbent assay, than DTP vaccinees had 1 month and 1 year after immunization. This APDT vaccine was immunogenic and caused fewer local reactions than conventional DTP vaccine when administered as a fourth dose to 17- to 24-month-old children.

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.

Comparison of acellular and whole-cell pertussis-component DTP vaccines. A multicenter double-blind study in 4- to 6-year-old children.

An acellular pertussis-component combined diphtheria and tetanus toxoids, and pertussis (APDT) vaccine adsorbed was compared with a licensed whole-cell pertussis-component combined diphtheria and tetanus toxoids, and pertussis (DTP) vaccine adsorbed for reactogenicity and immunogenicity when given as the fifth DTP immunization to eighty-two 4- to 6-year-old children. The reaction rates with both vaccines were low; APDT vaccine recipients had significantly less pain and warmth at the injection site than did DTP vaccine recipients. Antibody responses to pertussis antigens (lymphocytosis-promoting factor, filamentous hemagglutinin, and agglutinogens) and to diphtheria and tetanus toxoids were all brisk. The APDT vaccine recipients had a more marked response in antibodies to filamentous hemagglutinin and a less marked response in agglutinins than whole-cell vaccine recipients. On the day after immunization, both APDT and DTP vaccine recipients had an increase in mean leukocyte and neutrophil counts. This APDT vaccine is immunogenic and less reactogenic than a DTP vaccine with a whole-cell pertussis component when administered as a booster to 4- to 6-year-old children.