Evaluation of the COBAS® AmpliPrep/COBAS® TaqMan® HCV Test v2.0 for HCV viral load monitoring using dried blood spot specimens

This study evaluated the use of dried blood spot (DBS) for HCV viral load quantification using the COBAS^® AmpliPrep/COBAS^® Taqman^® HCV Quantitative Test v2.0 (CAP/CTM HCV v2), and compared two different procedures for preparation of DBS samples with a Specimen Pre-Extraction (SPEX) reagent (either heated [SPEX with SH] for 10min at 56°C on a thermomixer, or incubated for 1h at room temperature [SPEX at RT]) against the standard plasma input. Whole blood specimens from 48 patients with chronic HCV infection and Whatman^® 903 Protein Saver Cards were used to prepare 35μL DBS. An aliquot of plasma was spun and frozen from each draw. Mean DBS viral load results were compared to the corresponding results from plasma. Correlation between DBS to plasma was linear for both SPEX with SH (R²=0.96) and SPEX at RT (R²=0.97) procedures, with a constant negative offset of approximately 2.0log₁₀IU/mL between whole blood DBS without any adjustments and plasma results. After volume corrections, the mean offset to plasma decreased to -0.39 and -0.36 for the two procedures, respectively. The study demonstrated the use of DBS for HCV viral load correlates well with plasma with a constant offset.

Safety and immunogenicity of live attenuated quadrivalent human-bovine (UK) reassortant rotavirus vaccine administered with childhood vaccines to infants

The safety and immunogenicity of an orally administered, live rotavirus vaccine comprised of four strains, each with a titer of 10(5.3) or 10(5.8) pfu, and each having 10 genes from the UK bovine strain and the VP7 gene from human rotavirus serotype 1, 2, 3, or 4, were evaluated in adults, young children and infants in randomized, double-blind phase 1 trials. Three doses of rotavirus vaccine or placebo given with childhood immunizations to infants at 2, 4, and 6 months of age were well tolerated and did not inhibit antibody responses to childhood vaccines which included DTP, Hib, hepatitis B and OPV. Serum rotavirus antibody responses were detected in 12 of 20 infants after 1 dose, and in 19/19 of the vaccinees after three doses. Neutralizing antibody responses were detected more often against the bovine rotavirus UK strain (95%) than to human rotavirus VP7 serotypes 1 (37%), 2 (32%), 3 (32%) or 4 (32%). The efficacy of this quadrivalent rotavirus vaccine needs to be evaluated further.

Evaluation of a single dose of diphtheria-tetanus toxoids among adults in Odessa, Ukraine, 1995: immunogenicity and adverse reactions

Epidemic diphtheria spread to Ukraine in 1991, where it peaked in 1995 with >5,000 reported cases. To refine epidemic control strategies, immunogenicity of a tetanus-diphtheria toxoids vaccine (Td) containing 2 limits of flocculation (Lf) diphtheria toxoid was evaluated. During a mass vaccination campaign, adults at a clinic in Odessa received one dose of Td. At enrollment, 57.2% of 341 study participants had levels of diphtheria antitoxin (DAT) >/=0.1 IU/mL. Thirty and 180 days after receiving one dose of Td, 91.5% and 84.5% of the participants, respectively, had DAT levels >/=0.1 IU/mL. However, among 40- to 49-year-old participants, only 78.8% and 73.8% had DAT levels >/=0.1 IU/mL at 30 and 180 days, respectively. This study suggests that one dose of 2 Lf diphtheria toxoid is highly effective in raising DAT to protective levels in most adults; however, the study also shows that certain age groups, particularly persons 40-49 and, to a lesser degree, 30-39 years old may require additional doses or a complete three-dose primary vaccination series for optimal protection against diphtheria.

Evaluation of a single dose of diphtheria toxoid among adults in the Republic of Georgia, 1995: immunogenicity and adverse reactions

To determine the immunogenicity and safety of a single dose of diphtheria toxoid among adults, blood samples for detecting serum antitoxin levels were obtained from 18- to 59-year-old subjects (n=248) before and 30 days after immunization with Td (tetanus-diphtheria toxoids; manufactured by Serum Institute of India). By day 30, the seroprevalence of antitoxin levels >/=0.1 IU/mL increased from 22.6% to 81.5%; median antitoxin levels increased from 0.01 to 4.0 IU/mL. These parameters were lowest among subjects who were 40-59 years old, especially among those 40-49 years old. Adverse reactions (local redness, swelling, induration, fever>39 degrees C) were reported by 5.3% of participants. Our findings suggest that, in general, one dose of the Indian-produced Td vaccine is efficacious and safe in inducing an adequate immune response against diphtheria in adults; however, in Georgia, persons 40-59 years old, especially those 40-49 years old, will require additional doses of toxoid to achieve protective levels of antitoxin.

Immunogenicity of tetanus-diphtheria toxoids (Td) among Ukrainian adults: implications for diphtheria control in the Newly Independent States of the Former Soviet Union

After 30 years of control, epidemic diphtheria returned to the Soviet Union in 1990. To develop control strategies, the immunogenicity of the tetanus and diphtheria toxoids (Td) vaccine was assessed. Workers who were 18-67 years old received two Td immunizations separated by 30 days. A neutralization assay determined diphtheria antitoxin (DAT) on enrollment and on days 7, 30, 60, and 425. On enrollment, 43.0% of 488 workers had DAT <0.1 IU/mL. After one dose, 88.5% had DAT >/=0.1 IU/mL, after two doses, 92.2% had >/=0.1 IU/mL and >90% of participants <30 or >/=50 years of age attained >/=1.0 IU/mL; however, only 78.4% of those who were 30-39 years old and 51.8% of those who were 40-49 years old achieved >/=1.0 IU/mL after two doses. To control the epidemic in Ukraine, one Td dose should be administered to virtually the entire population (persons 30-49 years old require three doses of Td for optimal individual protection and to maximize population immunity).

Dose-response to a two-component acellular pertussis vaccine in infants and comparison with whole-cell vaccine

In an effort to determine the optimal dose of pertussis toxoid (PT) and filamentous haemagglutinin (FHA) for use in acellular pertussis vaccines we compared the immunogenicity and safety of acellular pertussis vaccine combined with diphtheria and tetanus toxoids containing 12.5 microg (DTaP-12.5) or 25 microg (DTaP-25) each of PT and FHA with a whole cell pertussis vaccine in infants immunized at 2, 4 and 6 months of age. Recipients of acellular vaccines developed higher anti-FHA concentrations and more rapid anti-PT serological responses that infants who received whole cell pertussis vaccine combined with diphtheria and tetanus toxoids (DPT). A dose response was noted; infants immunized with DTaP-25 developed significantly (P<0.03) higher anti-FHA and anti-PT levels than infants who received DTaP-12.5. No rise in the agglutinin titres was noted for recipients of the acellular vaccines although this vaccine stimulated increases in agglutinins when given as the fourth or fifth dose to children who had received three doses of DTP. The rates of erythema, induration, pain, irritability, crying, increased sleepiness, and decreased appetite were significantly (P</=0.05) lower in infants who received acellualr vaccines than in infants who received DTP. When the data from the injections at 2, 4 and 6 months of age were combined, no significant differences in the rates of any adverse event were noted for recipients of DTaP-12.5 or DTaP-25. The rates of most adverse reactions following DTP decreased from the first to the third immunization except fever, which increased. For acellular vaccine recipients, the rates of fever and erythema increased somewhat from the first to the third injection but remained far below the rates following DTP. The acellular vaccine was safe and immunogenic, and a dose-response effect was demonstrated.

A safety and immunogenicity comparison of 12 acellular pertussis vaccines and one whole-cell pertussis vaccine given as a fourth dose in 15- to 20-month-old children

OBJECTIVE

To compare the safety and immunogenicity of 12 different acellular pertussis vaccines combined with diphtheria and tetanus toxoids (DTaP) with one licensed diphtheria, tetanus, and whole-cell pertussis vaccine (DTwP) as a fourth-dose booster in children who had previously received DTaP or DTwP primary vaccinations.

METHODS

Healthy 15- to 20-month-old children were enrolled at six National Institutes of Health Vaccine Treatment and Evaluation Units. All had been randomly assigned to receive three primary doses of DTaP or DTwP at 2, 4, and 6 months of age as part of an earlier National Institutes of Health multicenter trial of DTaP vaccines in the same Vaccine Treatment and Evaluation Units. Parents recorded the occurrence and magnitude of fever; irritability; and injection site redness, swelling, and pain for 3 days after vaccination. Sera obtained before and 1 month after the booster vaccination were analyzed for antibody to pertussis toxin (PT), filamentous hemagglutinin (FHA), fimbriae (FIM), and pertactin (PRN). Diphtheria and tetanus toxoid as well as PT neutralizing (Chinese hamster ovary cell) and whole-cell agglutinating antibodies were measured on a subset of sera.

RESULTS

A total of 1293 children contributed fourth-dose reaction data. Reactions were less frequent after DTaP than after DTwP. For children vaccinated with a fourth dose of DTaP, which was the same DTaP as received in the primary series, fever and injection site redness, swelling, and pain increased in prevalence compared with the third dose in the primary series. For children receiving DTaP as a fourth dose, injection site redness and swelling occurred more frequently in DTaP-primed than in DTwP-primed children. Variation in the occurrence of reactions among DTaP vaccines was observed. A total of 1160 paired pre- and postvaccination sera were available for analysis. Serum antibody concentrations before boosting were lower than those obtained 1 month after the primary immunization. After the fourth dose, significant increases in antibodies directed against the included antigens were observed for all vaccines; postbooster vaccination antibody titers differed significantly among the DTaP vaccines. For children primed and boosted with the same DTaP, antibody levels were not directly related to the quantity of antigen included for PT, FHA, and FIM; for PRN, there was a closer relationship. Some DTaP vaccines given as fourth-dose boosters elicited antibody to PRN or FIM in some vaccinees, although the DTaP vaccines were not reported to contain these antigens; these responses were observed more frequently in DTwP-primed children. Agglutinin antibody rises were observed in all groups immunized with four doses of a DTaP vaccine containing FHA or PRN, regardless of whether the vaccine included FIM. Diphtheria and tetanus antibody levels exceeded the presumed protective concentration (0.1 IU/mL for diphtheria and 0.01 IU/mL for tetanus) after the fourth dose for all vaccinees.

CONCLUSION

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.

Response to the varicella vaccine in children with nephrotic syndrome

Varicella vaccine was administered to seven children with corticosteroid-sensitive nephrotic syndrome. Immunization was not associated with any significant reactions or with increased frequency of relapse. The antibody response was, however, variable and a second dose was necessary before seroconversion was achieved in four patients. The findings indicate that immunization with varicella vaccine is safe in children with nephrotic syndrome in remission, but that a two-dose vaccine schedule should be considered.

Intravenous immunoglobulin prophylaxis of cytomegalovirus infection in pediatric renal transplant recipients

Cytomegalovirus (CMV), the most significant infectious cause of morbidity following renal transplantation, may be a greater problem for children than for adults due to their relative lack of experience with this virus. Therefore, we prospectively gave Gammagard as prophylaxis to CMV-negative children who received CMV-positive allografts and compared the results to our experience with similar high-risk recipients transplanted prior to our use of intravenous immunoglobulin G (IvIgG). Symptomatic CMV disease developed in 17% of the IvIgG recipients as compared with 71% of the untreated patients (p = 0.01). The CMV infections that did occur in IvIgG recipients developed significantly later than in untreated children (median time of onset after transplantation 2.60 vs. 1.35 months; p < 0.05) and generally were less severe, although 1 IvIgG recipient died despite prophylaxis. IvIgG administration did not affect the frequency of rejection or graft or patient survival. We conclude that IvIgG administration to high-risk pediatric renal transplant recipients may protect against posttransplantation CMV disease and may lessen the severity of infections that do develop in patients who receive it.

Effective immunization against influenza in pediatric renal transplant recipients

Viral infections such as influenza are an important cause of morbidity following organ transplantation. We evaluated the immunogenicity of a commercially available influenza vaccine in pediatric renal transplant recipients in a two-phase, prospective study. In phase one, 47 transplant patients and seven control subjects with bronchopulmonary dysplasia received influenza vaccine. Sera were collected at the time of vaccination and 6 wk later. In phase two, sera from 18 transplant recipients and 47 healthy adults who had received the same vaccine were collected 6-12 months after vaccination. Antibody titers to the A/Taiwan/1/86 antigen were measured with hemagglutination inhibition assay in both phases of the study. Vaccine was well tolerated in all subjects. No vaccinated patient required hospitalization for complications of influenza infection. Vaccination did not increase the frequency of acute allograft rejection. In phase one, 43 patients (91%) and 5 controls (71%) either seroconverted (developed a fourfold or greater rise in titer), or developed post-vaccination titers > or = 1:160 (p = NS). Among the transplant recipients, non-seroconverters had a higher pre-vaccination geometric mean antibody titer (GMT) than those who seroconverted. Seroconversion developed independently of whether patients received double or triple immunosuppression. In phase two, post-vaccination GMT were similar for patients and control subjects at 11.5 and 8 months post-vaccination, respectively. In our study, influenza vaccination produced equivalent humoral immunity in transplant recipients and normal subjects. Routine influenza vaccination should be performed annually in this high-risk population.

The effect of maternal antibody on the serologic response and the incidence of adverse reactions after primary immunization with acellular and whole-cell pertussis vaccines combined with diphtheria and tetanus toxoids

OBJECTIVE

To evaluate the effect of maternally derived antibody on the immunogenicity and reactogenicity of acellular (DTaP) or whole-cell (DTP) pertussis vaccine with diphtheria and tetanus toxoids combined.

METHODS

A total of 2342 infants were randomized to receive one of 13 DTaP or 2 DTP vaccines at 2, 4, and 6 months of age. The correlation between preimmunization and postimmunization antibody after three doses of vaccine and the relation between preimmunization antibody and adverse reactions after the first immunization were modeled by linear regression.

RESULTS

After DTP but not DTaP, higher levels of preexisting antibody were associated with substantial (28% to 56%) reductions in the subsequent antibody response to pertussis toxin (PT). For other pertussis antibodies, modest inverse correlations were seen between preexisting antibody concentrations and most postimmunization antibody responses (resulting in 8% to 18% reductions in postimmunization antibody) for both DTP and DTaP. There was no consistent association in any DTP or DTaP group between adverse reactions and preimmunization antibody levels.

CONCLUSION

The PT antibody response to DTaP, unlike DTP, is not adversely affected by preexisting antibody to PT. Inhibitory effects with respect to other antibodies, seen with both DTP and DTaP, were relatively modest. Our data suggest that the use of acellular pertussis vaccines in adults, which could confer higher levels of antibody in women before pregnancy, would be unlikely to adversely affect pertussis antibody responses after DTaP among infants born to mothers with high antibody levels.

Description and evaluation of serologic assays used in a multicenter trial of acellular pertussis vaccines

OBJECTIVE

To describe and evaluate the assays used to measure the antibody responses in infants to 13 experimental acellular pertussis vaccines and 2 licensed whole-cell pertussis vaccines.

METHODS

During a 53-week period, preimmunization and postimmunization sera were assayed for immunoglobulin G antibodies to pertussis toxin, filamentous hemagglutinin, pertactin, and a mixture of type 2 and type 3 fimbriae by enzyme-linked immunosorbent assay (ELISA), for whole-cell agglutinins (AGG), and for pertussis toxin-neutralizing antibodies by the Chinese hamster ovary cell assay. All ELISA reagents were characterized to assure antigen and isotype specificity of the assays. Intralaboratory reproducibility and temporal stability were evaluated by analysis of results of control sera and by assessment of the response to the control whole-cell vaccine. Interlaboratory reproducibility was assessed by repeating the assays on preimmunization and postimmunization sera for 10% of the infants in a second laboratory.

RESULTS

For control sera having antibody concentrations at least four times the minimum level of detection, the coefficients of variation within and between the ELISAs consistently were less than 20%. Trend analysis indicated that none of the assays drifted by more than 20% during the study period, and no significant drift was seen in the response to the control whole-cell vaccine. Results from the two laboratories correlated well; correlation coefficients were .93 or greater for the four ELISAs, .79 for the Chinese hamster ovary cell assay, and .82 for the AGG assay. For four of the six assays, there was either no difference or a modest (< 15%) difference in the geometric mean values for sera tested in both laboratories. Larger quantitative differences were observed for the AGG (45% difference) and pertactin (61% difference) assays.

CONCLUSION

Assay reproducibility and stability indicate that the standardized methods can be transferred between laboratories, and that the results accrued during a 1-year period for the 15 vaccines can be compared.

Relationships between functional assays and enzyme immunoassays as measurements of responses to acellular and whole-cell pertussis vaccines

OBJECTIVE

To examine the relationships between functional assays and antigen-specific enzyme immunoassays in sera from a multicenter trial of 13 different experimental acellular pertussis vaccines and 2 licensed whole-cell vaccines, and to determine whether correlations previously observed among assays of specimens from pertussis patients and whole-cell vaccinees would apply to specimens from infants immunized with purified components in acellular vaccines.

METHODS

Postimmunization sera were assayed for immunoglobulin G antibodies to pertussis toxin (PT), filamentous hemagglutinin, pertactin (PRN), and a mixture of types 2 and 3 fimbriae (FIM) by enzyme-linked immunosorbent assay, for whole-cell agglutinins (AGGs) and for PT-neutralizing antibodies by the Chinese hamster ovary (CHO) cell assay. Assay results were compared for individual sera, as well as for geometric mean antibody concentrations or titers (GMTs) calculated by vaccine or overall.

RESULTS

For the 15 vaccines, the PT GMTs were highly correlated with the CHO assay GMTs (r = .92), and the FIM GMTs were highly correlated with the AGG GMTs (r = .96). For individual postvaccination sera, there was a significant correlation between the CHO titers and levels of antibody to PT whether the 15 vaccines were considered separately (.59 < or = r < or = .85) or combined (r = .81). For individual sera from infants immunized with the two whole-cell vaccines or any of the four acellular vaccines containing FIM, a strong correlation between AGG titer and FIM antibody was observed whether the vaccines were considered separately (.83 < or = r < or = .91) or together (r = .86). One vaccine without detectable FIM produced a measurable AGG response; for this vaccine, a moderate but significant correlation (R = .58) between PRN antibody and AGG titer was observed.

CONCLUSION

These data indicate that appropriate antigen-specific enzyme-linked immunosorbent assays will furnish results similar to those provided by the CHO and AGG assays in the evaluation of the immunogenicity of component vaccines. Antibodies to FIM seem to include the most important AGGs; however, there is evidence that agglutination by PRN antibody may be detected in the absence of antibody to FIM.

Simultaneous administration of Haemophilus influenzae type b vaccine with acellular or whole-cell pertussis vaccine: effects on reactogenicity and immune responses to pertussis vaccines

OBJECTIVE

To evaluate the effect of simultaneous Haemophilus influenzae type b conjugate (Hib) vaccination on the safety and immunogenicity of selected acellular (DTaP) and whole-cell (DTP) pertussis vaccines with diphtheria and tetanus toxoids combined.

METHODS

Enrollment of infants into a large multicenter study of the safety and immunogenicity of 13 DTaP and 2 DTP vaccines was partially completed when the first Hib vaccine, HbOC (Haemophilus b oligosaccharide conjugate vaccine), was licensed for use in infants. Thereafter, at each immunization most infants received HbOC simultaneously with DTaP (or DTP), administered in opposite thighs. Postvaccination geometric mean titers or concentrations (GMTs) of pertussis antibodies as measured by six different assays were compared pairwise among groups of infants receiving 0, 1, 2, or 3 simultaneous HbOC immunizations. The incidence of reactions was compared between infants who received only DTaP or DTP and those who received HbOC simultaneously.

RESULTS

Comparison of postvaccination GMTs was possible among groups of infants receiving different numbers of simultaneous immunizations for 10 of the 13 DTaP and both DTP vaccines. Increased HbOC exposure had no consistent dose-response effect on antibody titers for DTaP or DTP vaccines in any assay. Significant differences between groups in postvaccination GMTs were observed with 4 DTaP vaccines in 1 to 2 assays each; the GMTs were higher with increasing HbOC exposure for 2 DTaP vaccines and lower for 2 others. There was no significant increase in reactions with simultaneous HbOC and DTaP immunization.

CONCLUSIONS

Based on these retrospective analyses, there did not seem to be an interference in pertussis immunogenicity or alteration in reactogenicity associated with the simultaneous administration of HbOC and DTaP. These findings are encouraging with respect to the development of DTaP-Hib combination vaccines.

Measles control in Kinshasa, Zaire improved with high coverage and use of medium titre Edmonston Zagreb vaccine at age 6 months

BACKGROUND

To improve measles control in Kinshasa, Zaire, a project to increase vaccine coverage was begun in 1988, and in 1989, the city vaccination programme changed measles vaccination policy from Schwartz vaccine at age 9 months to medium titre Edmonston Zagreb (EZ) vaccine at age 6 months. We report the impact of the programme on measles incidence and mortality.

METHODS

Data on vaccine coverage were obtained from cluster sample surveys conducted every 1-2 years and from routine reports of vaccine doses administered. Data on measles incidence and mortality were obtained from sentinel surveillance sites. The serological response to EZ measles vaccine was evaluated at a health centre in 1989 and in a community survey in 1990.

RESULTS

Measles vaccine coverage estimated in cluster surveys increased from 50% of the 1984 birth cohort to 89% of the 1989 birth cohort, accepting either a home-based record or a verbal history of vaccination. Reported measles incidence per 10,000 [corrected] population decreased by over 90%, from 37.5 in 1980 (early vaccination years) to 1.6 in 1991. There was a relative decrease in the proportion of cases aged < 9 months (32% of cases in 1986-1987 and 23% of cases in 1990-1991) and an increase in the proportion aged > 23 months (29% of cases in 1986-1987 and 43% in 1990-1991). According to ELISA assays, 74-76% of children seroresponded to EZ vaccine administered at age 6-7 months under routine programme conditions.

CONCLUSIONS

Measles can be controlled in urban areas, although it is difficult to determine how great a contribution vaccination at age 6 months makes over and above the achievement of high coverage.

Isotype and antigen specificity of pertussis agglutinins following whole-cell pertussis vaccination and infection with Bordetella pertussis

Elevated agglutinin titers have been shown to correlate with protection from disease following whole-cell pertussis vaccination, but the isotype and antigen specificity of human agglutinating antibodies is unknown. In 13 immunoassays, immunoglobulin G antifimbria antibodies had the strongest correlation with agglutinin titers following culture-proven infection with Bordetella pertussis (R' = 0.79; P < 0.0001) and following whole-cell pertussis vaccination (R' = 0.87, P < 0.0001).

Response of human immunodeficiency virus-infected adults to measles-rubella vaccination

Measles-mumps-rubella vaccine (MMR) is recommended for human immunodeficiency virus-infected (HIV+) adults. Data concerning MMR vaccination of HIV+ patients are limited to children. We evaluated 39 HIV+ (97% with > 200 CD4+ lymphocytes) and 17 non-HIV+ control adults receiving measles-rubella vaccine (MR). Clinical adverse events did not differ between groups. Prevaccination, three HIV+ and two control vaccinees were measles seronegative; no HIV+ and one control vaccinee seroconverted. No initially measles-seropositive vaccinee had a significant antibody elevation. Four HIV+ and three control vaccinees were rubella seronegative prevaccination; three HIV+ and two control vaccinees seroconverted. Among those initially rubella seropositive, two HIV+ and one control vaccinee had significant antibody elevations. There were no significant percentage CD4+ or CD8+ lymphocyte changes between groups. Three HIV+ vaccinees were p24 antigen positive pre- and postvaccination. Although MR vaccination appears safe in HIV+ adults, questions remain about the response of measles and rubella antibody-negative HIV+ adults and those with < 200 CD4+ lymphocytes.

Immunogenicity of high-titer Edmonston-Zagreb measles vaccine in human immunodeficiency virus-infected children in Kinshasa, Zaire

The response to Edmonston-Zagreb vaccine (titer, 5.4 log10 pfu) was evaluated among children in a study of perinatal transmission of human immunodeficiency virus (HIV) in Kinshasa. Acute postvaccination adverse events were monitored for 49 HIV-infected and 376 non-HIV-infected infants, and measles antibody responses were assessed by ELISA for 34 HIV-infected and 255 non-HIV-infected infants. There was no increase in the incidence of common symptoms 7-10 days after vaccination. HIV-infected infants were more likely to have detectable prevaccination measles antibody, and seroconversion after vaccination was somewhat lower in HIV-infected (76.5%) than non-HIV-infected infants (85.5%). Seroconversion rates did not differ among children with or without rhinitis or fever at vaccination. High-titer Edmonston-Zagreb vaccine given at 6 months of age has the potential to provide earlier protection against measles; however, this vaccine is no longer recommended for routine use, and two doses of standard-titer vaccines remains the preferred option for measles vaccination of HIV-infected infants.

Safety and immunogenicity of bacille Calmette-Guérin, diphtheria-tetanus-pertussis, and oral polio vaccines in newborn children in Zaire infected with human immunodeficiency virus type 1

OBJECTIVE

To determine the safety and immunogenicity of childhood vaccines in children with perinatally acquired human immunodeficiency virus type 1 (HIV-1) infection.

DESIGN

Nonrandomized, prospective cohort study; 12-month follow-up period.

SETTING

Obstetric wards and outpatient pediatric clinics at two large hospitals in Kinshasa, Zaire.

PATIENTS

A total of 8108 pregnant women were screened for HIV-1 antibodies. The 474 children born to 466 seropositive women identified during screening and the 616 children born to 606 seronegative, age- and parity-matched women were vaccinated.

INTERVENTION

The following vaccines were administered at the stated ages: bacille Calmette-Guérin (BCG) vaccine (2 days); trivalent oral Sabin poliomyelitis vaccine (2 days and 6, 10, and 14 weeks); and adsorbed diphtheria-tetanus-pertussis (DTP) vaccine (6, 10, and 14 weeks).

MEASUREMENTS AND MAIN RESULTS

Protective antibody titers to tetanus and poliovirus types 1, 2, and 3 were achieved in 95% of all children. Among children with HIV-1 infection, 70.8% had protective antibody titers to diphtheria compared with 98.5% of uninfected children (p < 0.05). Geometric mean antibody titers to diphtheria and poliovirus types 1, 2, and 3 were significantly lower in children with HIV-1 infection than in uninfected children. Vaccine-associated side effects were similarly low in all children.

CONCLUSIONS

The low incidence of side effects and the high proportion of children with HIV-1 infection who achieved protective postimmunization antibody titers support the continuing use of BCG, DTP, and oral polio vaccines in childhood immunization programs in HIV-1 endemic areas.

Response to measles-mumps-rubella vaccine in children on dialysis

Ten children receiving maintenance dialysis were immunized with the standard dose of measles-mumps-rubella vaccine between 15 and 33 months of age. Immune responses to vaccination were determined using commercially available enzyme-linked immunosorbent assays for measles, mumps, and rubella viruses. Eight children responded to measles vaccine, 5 to mumps vaccine, 8 to rubella vaccine, and only 3 children to all three vaccines, compared with a seroconversion rate of over 90% to all three vaccines in healthy children (P less than 0.0001). We contend that the relatively poor immunocompetence of our dialysis patients explains their less than optimal vaccine response and suggest that children vaccinated while undergoing dialysis be tested to confirm serological evidence of immunity.

Dose-response to acellular pertussis vaccine and comparison with whole cell pertussis vaccine at 15-24 months and 4-6 years of age. Acellular Pertussis Vaccine Study Team

In a randomized double-blind trial 55 children of 15-24 months and 56 children of 4-6 years of age previously immunized with whole-cell DTP (WC-DTP) received acellular pertussis DTP vaccines containing 12.5 micrograms (AC-12.5) or 25 micrograms (AC-25) each of pertussis toxoid (PT) and filamentous haemagglutinin (FHA) per dose of WC-DTP. No differences in antibody responses or adverse events were noted for children who received AC-25 as compared with AC-12.5. All three groups had significant increases in pertussis agglutinins, but the geometric mean titre (GMT) for 4-6-year-old children who received WC-DTP was higher than the GMT for children who received acellular vaccine. No significant differences were noted in the GMT of antibodies to FHA or PT between children who received WC-DTP and recipients of acellular vaccine. The rates of several adverse reactions were significantly (p less than or equal to 0.05) higher for recipients of WC-DTP, and children given WC-DTP were significantly (p less than or equal to 0.00001) more likely to have received acetaminophen. These acellular vaccines are safe and as immunogenic for FHA and PT as WC-DTP when administered as the fourth or fifth dose to children who received three doses of WC-DTP in infancy. The lower (12.5 micrograms) dose of acellular vaccine was as effective as the higher (25 micrograms) dose in inducing antibodies to FHA and PT in children 15-24 months and 4-6 years of age.

Immunization response varies with intensity of acute lymphoblastic leukemia therapy

Twenty-four children receiving maintenance chemotherapy for acute lymphoblastic leukemia were given booster doses of tetanus-diphtheria combined toxoids. One month later, 19 of the 24 children were given Haemophilus influenzae B oligosaccharide-cross-reacting material conjugate vaccine. Following immunization, all patients had protective antibody titers against tetanus, 92% had protective antidiphtheria titers, and 84% had protective titers against H influenzae. Preimmunization titers, postimmunization titers, and response to immunization varied according to the intensity of therapy. There was no correlation with duration of therapy or quantitative hematologic values in the peripheral blood. These observations support the recommendation that children treated for acute lymphoblastic leukemia should be immunized against H influenzae B.

Human serologic response to envelope-associated proteins and adenylate cyclase toxin of Bordetella pertussis

The human serologic response to several envelope-associated proteins and adenylate cyclase toxin of Bordetella pertussis was examined using immunoblot techniques. Antigens recognized by sera from individuals with culture-confirmed pertussis and by sera from infants immunized with three doses of conventional whole-cell pertussis vaccine included a 63,000-Da protein that was shown to be antigenically related to a mycobacterial heat-shock protein. A 29,000-Da protein reacted with sera from convalescent individuals, whereas a 91,000-Da protein reacted with sera from vaccinated individuals. Antibodies to adenylate cyclase toxin were common in sera from individuals diagnosed with pertussis. B. pertussis lipooligosaccharide was also recognized by antibodies in some of these sera. These data suggest that some of these antigens may play a role in immunity to pertussis.

Serologic evidence of subclinical pertussis in immunized children

Incidental to a vaccine study involving 783 immunized children conducted at two study sites, inner city children had significantly higher geometric mean pertussis agglutinin titers compared with suburban children just before the fourth dose of diphtheria-tetanus-whole cell pertussis vaccine (47 vs. 25; P less than 0.001). Higher titers in the inner city were correlated with residence in census tracts where cases of pertussis were reported. Three hundred thirty-two children in a placebo arm of the study who were clinically observed and had paired serum samples taken during a 2- to 4-month period were analyzed for evidence of natural Bordetella infection. Twelve (11%) inner city children and three (1.3%) suburban children had spontaneous 4-fold or greater rises in at least two different pertussis antibodies measured (agglutinin, antitoxin or enzyme-linked immunosorbent assay for IgG to pertussis toxin, IgG and IgA to filamentous hemagglutinin). Eighty percent of these children had IgA to filamentous hemagglutinin. Nine of 12 inner city children with serologic evidence of pertussis lived within 6 blocks of a case of pertussis reported within 1 month of the observed antibody rise in study subjects; none had a household member with pertussis and none had symptomatic disease.

Impact of treatment guidelines on use of ribavirin

During the 1987 through 1988 seasonal peak of respiratory syncytial virus (RSV), 177 courses of ribavirin were administered at St Christopher's Hospital for Children, a tertiary care medical center in Philadelphia, Pa. Charts were reviewed on 100 treated patients with proved or suspected RSV disease to determine adherence to American Academy of Pediatrics treatment guidelines. Ninety-four percent fulfilled criteria for the risk of significant morbidity: cardiac, pulmonary, or immunodeficiency conditions (38%); an age of 6 weeks or younger (35%); or severe illness (21%). Severe illness was defined as hypoxemia, hypercapnia, or marked tachypnea. Of those treated because of underlying conditions, 71% had RSV documented, as did 71% of patients aged 6 weeks or younger and 81% of patients with severe disease. A study of 80 consecutive patients who were hospitalized with illness compatible with RSV infection revealed that 56% of patients were treated with ribavirin. Adherence to guidelines led to ribavirin use in half of the hospitalized patients with suspected RSV infection. The majority of these patients received therapy because of underlying conditions or very young age.

Longitudinal study of adverse reactions following diphtheria-tetanus-pertussis vaccine in infancy

A prospective study of immunogenicity and adverse effects of 1553 doses of diphtheria and tetanus toxoids and whole cell pertussis vaccine (DTP) was performed in 538 children observed longitudinally from 2 months to 20 months of age. Subjects were randomized to the standard four-dose immunization schedule or to a three-dose schedule (with a saline injection substituted for DTP at 6 months of age). The three-dose schedule could not be recommended on the basis of serologic data. Compliance for completing a clinical observation form in the 48 hours following injections was greater than 99%. Fever, local reactions, or adverse behavioral effects were described in association with 96% of DTP doses and 36% of placebo injections. Contraindications to DTP immunization developed in 3% of study children. No convulsion, hypotonic hyporesponsive episode, encephalopathy, or temperature greater than 40.5 degrees C occurred. Behavioral and local inflammatory effects occurred maximally in the first 6 hours following vaccine but fever peaked later. There was no interrelationship between occurrence of local reaction and fever. Data suggest that age has more effect on the type and rate of adverse clinical events than does vaccine dose number. Existing antibody levels to vaccine components, lot of vaccine, breast-feeding, or gestational age did not affect rate or type of clinical reactions. Neither occurrence of reactions nor the use of acetaminophen affected antibody response to vaccine.

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.