Adverse reactions and immunogenicity in adults to regular and increased dosage of diphtheria vaccine

Environmentally and occupationally acquired diseases in adolescents and adulthood: control of diphtheria, tetanus, pertussis, and poliomyelitis through regular booster vaccinations--a European perspective

Despite the success of childhood vaccination in industrialized countries, diphtheria, tetanus, pertussis (whooping cough), and poliomyelitis (polio) still affect adults and adolescents whose immunity has waned. The resurgence in the 1990s of diphtheria in the area of the former Soviet Union and its subsequent control with immunization campaigns, demonstrates the value of continued adult vaccination. Tetanus cannot be eradicated from the soil reservoir, necessitating routine primary vaccination and regular booster doses to maintain protective immunity. Although Europe has been certified endogenous polio-free since June 2002, polio imported from endemic areas continues to pose a serious threat for vulnerable populations. Booster polio vaccination is required in adolescence and adulthood. Pertussis among adults and adolescents is underestimated, representing a considerable health burden. The consequences can be more serious as this pool of susceptible adolescents and adults is a major source of pertussis transmission to newborns not yet protected by vaccination. The now available acellular pertussis-based combination vaccine covering diphtheria, tetanus, polio, and pertussis, suitable for adults and adolescents, provides the ideal tool for implementing booster immunization programs. Strong recommendations for adolescent and adult boosters are needed to overcome the continued threat of these diseases.

Effect of infant immunisation with meningococcus serogroup C-CRM(197) conjugate vaccine on diphtheria immunity and reactogenicity in pre-school aged children

The majority of Men C conjugate vaccines given in the UK use CRM(197), a mutant diphtheria toxoid, as their protein carrier. We studied the effects of prior immunisation with Men C-CRM(197) conjugate vaccine on immunity to diphtheria in 193 children before and after a booster dose of Men C at 4 years. Baseline diphtheria antibodies were higher in children given four previous doses of Men C (P<0.0001) and tended to be higher following boosting in those who had received three or four doses. This enhanced immunity was not associated with increased reactogenicity.

Reactogenicity and immunogenicity of adult versus paediatric diphtheria and tetanus booster dose at 6 years of age

We evaluated the reactogenicity and immunogenicity of a booster dose of diphtheria-tetanus vaccine administered at the age of school-entry, comparing a low-dose vaccine (dT) to the standard paediatric dose (DT). Participants were randomly assigned to receive one of the two vaccines; the study was evaluator-blinded. The frequency of side-reactions was similar when comparing the two groups, except when considering local redness and swelling, which were significantly more frequent among the DT group. The post-booster geometric mean titre of diphtheria antibodies in the DT group was twice as high as that in the dT group (14.1 IU/ml versus 7.7 IU/ml; P<0.001). The higher antibody response and the comparable reactogenicity indicate that DT should be used as booster at school-entry, particularly if additional booster doses during adolescence or adulthood are not administered.

Immune status and booster effects of low doses of tetanus toxoid in Swedish medical personnel

Of 102 medical staff at a Swedish hospital, 81% had tetanus antitoxin titres > or = 0.01 IU/ml in 1984-85. The unprotected individuals (antitoxin titre < 0.01 IU/ml) were all > 30 years of age. Of this group, one-third lacked a protective antibody level against tetanus toxin. Low booster doses of tetanus toxoid (0.75 or 1.9 Lf) were given to 66 vaccinees with a history of previous basic vaccination and no history of booster vaccination within the previous 5 years. The median titre increased from 0.26 IU/ml before to 3.3 IU/ml after vaccination. Low doses of tetanus toxoid may thus still provide an adequate immune response when given as a booster vaccination to individuals with a reliable history of basic immunization.

Increased dosage of diphtheria toxoid for basic immunization of adults

Basic immunization of adults with increased dosages of a diphtheria toxoid vaccine (2100 flocculation units (Lf)/mg) was evaluated. Three injections of 7.5 Lf or 15 Lf diphtheria toxoid were given to 243 adults who had a history of no more than one previous vaccine injection. Systemic reactions were rare in both groups. Following the first two injections, local reactions (greater than 5 cm) were observed in 6-14% of the adults. After the third injection, 35% of adults in the 15 Lf group reported a local reaction (greater than 5 cm) compared to 11% in the 7.5 Lf group (p less than 0.001). The 15 Lf dose elicited a better antitoxin response than the 7.5 Lf dose. In a seronegative subgroup including 65 vaccinees who showed no booster response to the first vaccination, 79% had a postvaccination titer of greater than or equal to 0.1 IU/ml and 28% a titer of greater than or equal to IU/ml after the third injection of 7.5 Lf. The corresponding numbers in the 15 Lf group were 94% and 44%, respectively. The study demonstrates that 7.5 Lf and 15 Lf diphtheria toxoid of high purity can safely be given to adults for basic immunization. The higher dose is more immunogenic but local reactions increase after the third injection.

Immune status and booster effects of low doses of diphtheria toxoid in Swedish medical personnel

During a diphtheria outbreak among Swedish alcoholics in 1984-1985, only 60% of 328 medical staff at risk for exposure had diphtheria antitoxin titers greater than or equal to 0.01 IU/ml, which is usually considered to give relative protection. 21% had levels between 0.01-0.09 IU/ml and the remaining 39% had titers greater than or equal to 0.1 IU/ml. Booster doses of 0.5 Lf-12.5 Lf of diphtheria toxoid were given to 450 vaccinees. Of 72 individuals with low pre-immunization titers, who were immunized with less than or equal to 2.5 Lf diphtheria toxoid, 40% failed to reach greater than or equal to 0.1 IU/ml when analyzed 4 weeks after vaccination. Local tenderness and swelling greater than 5 cm at the site of injection or general discomfort was found in 11% of those immunized with low dose diphtheria toxoid (less than or equal to 2.5 Lf). When the dose 0.5 Lf of diphtheria toxoid was combined with tetanus toxoid (3.75 Lf) the frequency of adverse reactions increased to 34% (p less than 0.001). The study shows that vaccination status in medical personnel must also be continuously examined in countries where diphtheria is rare and that low booster doses of diphtheria toxoid may not achieve an adequate immune response.