Primary immunization followed by a booster dose of PNCRM7 seemed to be acceptably safe and resulted in significant rises in antibody to all 7 serotypes. Implications. Studies to assess vaccine efficacy of PNCRM7 for prevention of systemic disease, nasopharyngeal colonization, and acute otitis media are in progress. If PNCRM7 proves to be protective, there is the potential to prevent up to 85% of invasive pneumococcal disease occurring in US children.

Context Increasing reports of pertussis among US adolescents, adults, and their infant contacts have stimulated vaccine development for older age groups.Objective To assess the immunogenicity and reactogenicity of a tetanus-diphtheria 5-component (pertussis toxoid, filamentous hemagglutinin, pertactin, and fimbriae types 2 and 3) acellular pertussis vaccine (Tdap) in adolescents and adults.Design, Setting, and Participants A prospective, randomized, modified doubleblind, comparative trial was conducted in healthy adolescents and adults aged 11 through 64 years from August 2001 to August 2002 at 39 US clinical centers.Interventions A single 0.5-mL intramuscular dose of either Tdap or tetanusdiphtheria vaccine (Td).Main Outcome Measures Antibody titers to diphtheria and tetanus toxoids for Tdap and Td were measured in sera collected from subsets of adolescents and adults, before and 28 days after vaccination. For pertussis antigens, titers in sera from Tdap vaccinees were assessed vs those from infants who received analogous pediatric diphtheria-tetanus-acellular pertussis vaccine (DTaP) in a previous efficacy trial. Safety was assessed via solicited local and systemic reactions for 14 days and adverse events for 6 months following vaccination.Results A total of 4480 participants were enrolled. For both Tdap and Td, more than 94% and nearly 100% of vaccinees had protective antibody concentrations of at least 0.1 IU/mL for diphtheria and tetanus, respectively. Geometric mean antibody titers to pertussis toxoid, filamentous hemagglutinin, pertactin, and fimbriae types 2 and 3 exceeded (by 2.1 to 5.4 times) levels in infants following immunization at 2, 4, and 6 months with DTaP. The incidence of solicited local and systemic reactions and adverse events was generally similar between the Tdap and Td groups.Conclusions This Tdap vaccine elicited robust immune responses in adolescents and adults to pertussis, tetanus, and diphtheria antigens, while exhibiting an overall safety profile similar to that of a licensed Td vaccine. These data support the potential routine use of this Tdap vaccine in adolescents and adults.

Although differences were observed in reaction rates among the DTaP vaccines given as a fourth dose, the DTaP vaccines were, in general, associated with fewer adverse events than a US-licensed DTwP. For DTaP vaccines, fever; irritability; and injection site pain, redness, and swelling occurred more frequently after the fourth dose than after the third dose of the same vaccine in the primary series. No DTaP was consistently most or least reactogenic or immunogenic. Although serologic correlates of pertussis immunity are not defined, it is clear that most DTaP vaccines can stimulate comparable or higher serum antibody responses than DTwP for those antigens contained in the vaccine.

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Inactivated poliovirus vaccine (IPV) is believed to induce significantly lower mucosal immunity than oral poliovirus vaccine (OPV). Most of the data supporting this were generated before enhanced IPV (eIPV) was introduced. Excretion of poliovirus by OPV recipients can be used to assess intestinal immunity. We studied polymerase chain reaction amplification of viral complementary DNA from the stool of children vaccinated with either OPV alone or eIPV. Of first-time OPV recipients, 92% excreted virus after 1 week, and 81% excreted virus after 3 weeks. Prior vaccination with OPV reduced the number to 22% and shortened the duration of virus excretion (to 5% after 3 weeks). Two doses of IPV reduced the number of poliovirus-positive 1-week samples (to 76%), the duration of shedding (to 37% at 3 weeks), and the quantity of excreted virus. This suggests that IPV-vaccinated communities are partially protected from the spread of poliovirus. Further enhancement of IPV potency may lead to even higher levels of mucosal immunity.

Booster doses of DTaP vaccines can cause entire limb swelling, which is usually associated with redness and pain. Our data suggest that this extensive swelling reaction may be more common with vaccines containing high diphtheria toxoid content.

MCV-4 appears to have a reactogenicity profile acceptable to parents and health care providers. It was only modestly immunogenic in infants, but it appeared to prime the immune system of the majority of infants given three doses in infancy. There is no statistically significant immunologic advantage conferred by increasing the dosage beyond 4 microg/ml, and local reactions are more frequent after the 10-microg/ml dosage.

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