Serum antibody responses after intradermal vaccination against influenza.

BACKGROUND: If found to be safe and immunogenic, reduced doses of influenza vaccine given by the intradermal route could increase the number of available doses of vaccine. METHODS: In an open-label study, we randomly assigned 119 subjects to receive an intradermal injection of trivalent inactivated influenza vaccine, containing 6 mug of hemagglutinin for each antigen (40 percent of the usual dose), and 119 to receive an intramuscular injection of the standard dose of 15 mug of hemagglutinin for each antigen. The two groups were subdivided according to age (18 to 60 years and older than 60 years). RESULTS: Among subjects who were 18 to 60 years of age, serum antibody responses were vigorous and did not differ significantly between the intradermal and intramuscular groups, and all subjects had hemagglutination-inhibition (HAI) titers of at least 1:40. Although the subjects who were older than 60 years of age also had a vigorous antibody response, there was a trend toward a better response in the intramuscular route, but this finding was significant only for antigen to the H3N2 strain. Nevertheless, 100 percent of older subjects in the intramuscular group and 93 percent of such subjects in the intradermal group had an HAI antibody titer to the H3N2 strain of more than 1:40, and 100 percent in each group had a titer of this level for both the H1N1 and B strains. Local pain was significantly more common in the intramuscular group than in the intradermal group among subjects who were 18 to 60 years of age but not among subjects who were over 60 years old. Signs of local inflammation were significantly more common among subjects in the intradermal group than among those in the intramuscular group, in both age groups. CONCLUSIONS: As compared with an intramuscular injection of full-dose influenza vaccine, an intradermal injection of a reduced dose resulted in similarly vigorous antibody responses among persons 18 to 60 years of age but not among those over the age of 60 years.

Safety and immunogenicity of a combination diphtheria-tetanus toxoids-acellular pertussis-hepatitis B vaccine administered at two, four and six months of age compared with monovalent hepatitis B vaccine administered at birth, one month and six months of age.

OBJECTIVE: To evaluate the safety and immunogenicity of diphtheria-tetanus toxoids-acellular pertussis (DTPa)-hepatitis B (HepB) combination vaccine given at 2, 4 and 6 months of age compared with monovalent HepB vaccine given at birth, 1 month and 6 months of age and DTPa vaccine given at 2, 4 and 6 months of age. METHODS: Healthy infants were randomized to receive a combination DTPa-HepB vaccine (diphtheria and tetanus toxoids, acellular pertussis antigens and hepatitis B surface antigen), concomitantly with type b and oral poliovirus vaccines at 2, 4 and 6 months of age (Group 1) or HepB vaccine given at birth, 1 month and 6 months of age and DTPa, type b and oral poliovirus vaccines given at 2, 4 and 6 months of age (Group 2). Antibody responses were evaluated at birth, 2 months and 7 months of age. Safety was evaluated after each immunization using diary cards and parental interviews. RESULTS: One month after the third dose (7 months of age), the geometric mean concentration of antibody to hepatitis B surface antigen was approximately 3.5-fold higher in Group 2 than in Group 1 infants (3643 and 1052 mIU/ml, respectively; < 0.001). Nevertheless the rates of seroprotection to HepB (antibody to hepatitis B surface antigen > or =10 mIU/ml) in Groups 1 and 2 were similar, 99 and 100%, respectively. Also the postvaccination geometric mean concentrations and rates of seroprotection or vaccine response to all of the other vaccine antigens evaluated were similar or greater in Group 1 than in Group 2. The rates of adverse events were similar between the two groups, with fussiness and soreness at any injection site reported most frequently. CONCLUSIONS: The DTPa-HepB combination vaccine was safe and immunogenic when given to infants at 2, 4 and 6 months of age. Equivalent rates of seroprotection to hepatitis B were achieved despite a reduction of the interval between the second and third doses from 5 months in Group 2 to 2 months in Group 1. Hepatitis B-containing combination vaccines should reduce the number of vaccine injections required in childhood and maintain excellent seroprotection against multiple pathogens.

Impact of a birth dose of hepatitis B vaccine on the reactogenicity and immunogenicity of diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus-Haemophilus influenzae type b combination vaccination.

OBJECTIVES: To assess the impact of a birth dose of hepatitis B vaccine (HepB) on the reactogenicity and immunogenicity of a novel diphtheria-tetanus-acellular pertussis (DTaP)- HepB-inactivated poliovirus (IPV)/ type b (Hib) combination vaccine administered subsequently at 2, 4 and 6 months of age. METHODS: Neonates ( = 550) were randomized into two groups with regard to receipt of HepB at birth. All subjects in both groups received DTaP-HepB-IPV/Hib at 2, 4 and 6 months of age. Solicited local and general adverse events were recorded for 8 days after each dose. Antibodies to hepatitis B surface antigen were measured 1 month after the third dose of DTaP-HepB-IPV/Hib in a subset of 170 infants; titers of at least 10 mIU/ml were considered protective. RESULTS: The DTaP-HepB-IPV/Hib combination vaccine was well-tolerated in both groups. Of the infants who received a birth dose of HepB, 22.6% had severe (Grade 3) reactions after any of the three doses of DTaP-HepB-IPV/Hib combination vaccine compared with 23.2% of subjects who did not receive a birth dose of HepB (difference, -0.5%; 90% confidence interval, -7.4 to 6.1). Antibody to hepatitis B surface antigen titers were > or =10 mIU/ml for all tested infants. Geometric mean titers were 2996.2 and 1240.1 mIU/ml with and without a birth dose of HepB, respectively. CONCLUSIONS: A HepB birth dose does not increase the reactogenicity of a combination DTaP-HepB-IPV/Hib vaccine administered at 2, 4 and 6 months of age, and all tested subjects achieved protective anti-HBs titers (> or =10 mIU/ml), although geometric mean titers were higher when a birth dose of HepB was given.

Interchangeability of 2 diphtheria-tetanus-acellular pertussis vaccines in infancy.

OBJECTIVE: Currently, 4 diphtheria-tetanus-acellular pertussis (DTaP) vaccines are licensed for pediatric use in the United States, and 2 are commercially available. Although a single manufacturer's DTaP vaccine should be used for all 3 doses of the primary immunization series, some circumstances result in infants receiving DTaP vaccines from more than 1 manufacturer. The purpose of this study was to evaluate the safety and immunogenicity of a mixed sequence of 2 different DTaP vaccines. METHODS: In this multicenter, observer-blinded, controlled study, 449 infants were randomized into 1 of 3 groups (1:1:1 ratio) to receive Tripedia at 2, 4, and 6 months of age (control group); Tripedia at 2 and 4 months of age and Infanrix at 6 months of age; or Tripedia at 2 months and Infanrix at 4 and 6 months of age. Other vaccines were administered concurrently as separate injections according to the recommended childhood immunization schedule. Safety was monitored closely, and standard enzyme immunoassays were used to measure antibody concentrations to each antigen of the DTaP vaccines. RESULTS: The rates of injection-site and systemic adverse events were similar in each study group, and there were no clinically significant differences among groups after any dose. Infants in all 3 groups responded well to each antigen contained in both vaccines, with 97% to 100% seroprotection or vaccine response rates after the 3-dose primary series. Postvaccination geometric mean antibody concentrations and seroprotection or vaccine response rates to nearly all vaccine antigens were as high or higher in the mixed-sequence groups as in the control group. CONCLUSION: Initiating the primary immunization series with 1 or 2 doses of Tripedia and completing the 3-dose series with Infanrix is as safe and at least as immunogenic as administering Tripedia for all 3 doses.