Evaluation of ready-to-use and multi-dose influenza vaccine formats in large clinic settings.

Large immunization clinics are commonly held to deliver influenza vaccine to seniors and others. Vaccine is typically dispensed from multi-dose vials but pre-filled syringes are now available, offering time savings for vaccinators. To determine if the higher purchase price of such syringes is offset by savings in time and injection supplies, we did a controlled comparison of syringe and vial formats in two large, concurrent, community-based influenza vaccination clinics. Vaccine preparation and immunization times were carefully documented along with costs for vaccine purchase, storage and injection supplies. Servicing 1,000 clients required 27 nurse hours using syringes and 36 hours using vials but the savings for personnel ($234) and supplies ($1,190) using syringes were exceeded by higher vaccine cost ($2,090 premium) and extra storage costs ($260) for bulkier packaging. Depending upon product and packaging style, programs using vials are cheaper by $709-$926 per 100 doses delivered compared to using pre-filled syringes.

Effect of reminder notices on the timeliness of early childhood immunizations.

OBJECTIVE: To determine whether reminder notices would improve the timeliness of toddler-age vaccinations. DESIGN: Prospective, randomized, controlled trial. POPULATION STUDIED: Two convenience cohorts of 320 children due to receive either measles-mumps-rubella (MMR) vaccine (at 12 months of age) or diphtheria-pertussis-tetanus (DPT)-inactivated polio (IPV)- Haemophilus influenzae type b (Hib) booster vaccine (at 18 months of age). SETTING: Suburban community. INTERVENTIONS: Parents of the identified children were randomly assigned either to a group to receive a reminder notice of pending vaccinations or a control group that did not receive a notice at a ratio of 1:1. Immunization uptake was assessed eights weeks after the initial due date for vaccination. RESULTS: Information was obtained for 224 children in the MMR group and 227 children in the DPT-IPV-Hib booster group. MMR uptake within eight weeks of the due date was about 90% in both the test and control groups, probably because of publicity surrounding a local college-based measles outbreak. In the DPT-IPV-Hib group, reminder notices had no effect; the uptake rates within eight weeks of the due date were 73.7% to 75.2%. Delays in immunization resulted mostly from parents' scheduling problems and provider-recommended delays. More than half of the parents whose child had delayed immunization did not recall receiving the reminder notice. CONCLUSIONS: Mailed reminders did not increase on-time immunization rates in the second year of a child's life. A telephone call or a more memorable reminder notice may be better suited to catch the attention of parents.

Assessment of parent education methods for infant immunization.

OBJECTIVE: To assess whether a video about infant immunization could inform parents as well as human counselling (oral presentation). METHODS: Core information for parents about infant immunization was identified and packaged in an instructional video and a scripted oral presentation. Volunteer prenatal classes were randomly assigned a video or oral presentation. Participants completed pre- and post-test questionnaires covering the same 16 items. Scores were compared for each question and as a group means, using Fisher's exact test, 2-sided. RESULTS: 227 subjects participated, including 102 men and 124 women. Groups were similar in terms of gender mix, parenting experience and recent reading about immunization. Pre-test knowledge scores were similarly low between groups. Post-test scores were much higher but did not differ significantly between groups. CONCLUSIONS: In a prenatal classroom setting, video and oral presentations were equally effective in conveying key information about infant immunization.

What do parents learn by reading a DPT vaccine information form?

OBJECTIVE: Information forms are commonly used to inform parents about childhood vaccination. This study assessed the knowledge of mothers about pertussis and pertussis vaccine before and after reading a form about diphtheria-pertussis-tetanus (dpt) vaccine. DESIGN: A test was administered to mothers before and after the first vaccination of their infant. By random allocation, one-half of the mothers received the form (study group) in addition to the routine counselling by a public health nurse given to the others (control group). SETTING: Public health immunization clinics in suburban Vancouver, British Columbia. SUBJECTS: One hundred and fifty-one mothers who were scheduled to bring their infant for the first dpt immunization were recruited, of whom 145 (96%) completed the study. INTERVENTIONS: A test consisting of 20 true/false questions was administered by telephone two weeks before and two weeks after the first dpt vaccination. Additional data about sources of vaccine information, maternal education, number of children and maternal age were obtained. OUTCOME MEASURES: Mean scores and mean change in scores on test. RESULTS: The mean changes in scores between tests 1 and 2 in study and control groups were +22.2% and +6.9%, respectively, on the disease-related questions (P<0.001) and +14.6% and +10.7%, respectively, on the vaccine-related questions (P=0.16). The forms were considered to be very useful by the mothers and clearly enabled them to score higher on a test of their knowledge of pertussis and pertussis vaccine. CONCLUSIONS: Reading a dpt vaccine form enabled mothers to improve their knowledge of pertussis and pertussis vaccine.

Evaluation of Haemophilus influenzae type b conjugate vaccine (meningococcal protein conjugate) in Canadian infants.

OBJECTIVE: To assess adverse effects and immune responses with a three-dose series of Haemophilus influenzae type b meningococcal protein conjugate (PedvaxHIB or Hib.OMP) vaccine, including any immunological response alterations from concurrent administration with routine vaccines for infants. DESIGN: Randomized, controlled trial with treatment group crossover for dose 3. SETTING: Two public health units near Vancouver. PARTICIPANTS: One hundred and ten healthy infants eight to 14 weeks old were enrolled; 105 completed the study (95%). INTERVENTIONS: All participants received two doses of diphtheria-pertussis-tetanus (dpt) vaccine (at two and four months of age) and one dose of measles-mumps-rubella (mmr) vaccine at 12 months. In each instance, Hib.OMP was given either concurrently in another limb or after a delay of two weeks (after dpt) or four weeks (after mmr). MAIN OUTCOME MEASURES: Adverse effects, particularly fever and local erythema, were monitored by parents for 72 h after each dose of Hib.OMP vaccine. Five blood samples were taken at prescribed intervals to assess responses to each dose of Hib.OMP and to selected other vaccine antigens. MAIN RESULTS: Follow-up was obtained after all 322 doses of Hib.OMP. Local adverse effects were infrequent and mild: 13% had redness, 17% tenderness. Systemic effects in those given Hib.OMP alone included fever in 8%, irritability in 29%. Anti-polyribose-ribitol phosphate (prp) responses to Hib.OMP were not impaired by coadministration with dpt or mmr vaccines, nor were tetanus or diphtheria antitoxin levels or rubella or measles response rates affected. After two doses of Hib.OMP, 92% were seropositive and 64% had greater than 1.0 µg/mL of anti-prp. After three doses, 100% were seropositive and 82% exceeded 1.0 µg/mL. CONCLUSION: Hib.OMP vaccine was well tolerated, immunogenic and compatible with vaccines routinely given to infants in Canada.

Amino acid sequence of a deltalike toxin from Staphylococcus epidermidis.

A deltalike toxin produced by a clinical isolate of Staphylococcus epidermidis was purified, and the amino acid sequence was determined. The toxin molecule consisted of 25 amino acid residues and shared a high degree of molecular homology with delta toxin purified from a Staphylococcus aureus human isolate.

Delta toxin activity in coagulase-negative staphylococci from the bowels of neonates.

Coagulase-negative staphylococci are prominent in stools of neonates in some intensive care units and have been associated with necrotizing enterocolitis. A plausible mediator of bowel damage is delta-like toxin, which is produced in vitro by most coagulase-negative staphylococci, but factors influencing the expression of toxin in the bowel are unknown. We examined 105 coagulase-negative staphylococcus isolates from stools of neonates by using an enzyme-linked immunosorbent assay and detected delta toxin production by 92 isolates (88%). The amount present in 18-h broth cultures varied over 100-fold, from 933 to 125,000 ng/ml. All broths positive by enzyme-linked immunosorbent assay except one caused hemolysis of human erythrocytes. The threshold concentration for consistent cytotoxicity to fibroblasts was greater than or equal to 24,000 ng/ml. Only 56% of Staphylococcus epidermidis isolates were capable of producing this much toxin, and these were more often obtained from premature infants in intensive care than from healthy full-term infants (P = 0.003) and were more often resistant to multiple antibiotics (P less than 0.001). Cultures grown anaerobically seldom caused hemolysis (4 positive of 29 tested; P less than 0.001) because potency of the toxin was decreased (at least ninefold for S. epidermidis isolates). We conclude that only a portion of the fecal coagulase-negative staphylococci tested produced enough delta toxin in vitro to be cytotoxic, that such isolates have accumulated in our intensive care nursery, and that development of toxin-mediated bowel injury may also require a favorable redox potential within the host bowel.

Delta-like toxin produced by coagulase-negative staphylococci is associated with neonatal necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is a serious neonatal disorder of uncertain cause, although fecal bacteria have been implicated in some outbreaks. We examined coagulase-negative staphylococci (CONS) as possible etiologic agents. In our unit, CONS colonized the bowels of most infants studied, including 46% of 70 NEC cases (mean concentration, 10(9.1) CFU/g of stool). Over 90% of tested isolates produced a hemolysin resembling delta toxin of Staphylococcus aureus. Toxin purified from a NEC-associated isolate of Staphylococcus epidermidis resembled reference delta toxin from S. aureus in size, biologic properties, and antigenicity. This delta-like toxin was enteropathic, causing mucosal necrosis and hemorrhage in injected loops of the bowels of infant rats. Adjacent, nonexposed bowel remained normal, as did loops injected with lecithin-neutralized toxin. Using a new enzyme-linked immunosorbent assay (ELISA), we detected delta-like toxin in the stools of 11 of 35 infants colonized with CONS positive for delta-like toxin (Tox+). Positive tests were strongly associated with NEC. Of 18 cases with Tox+ CONS, 10 were positive (56%), whereas only 1 of 17 control infants so colonized was positive (6%, P = 0.002). In NEC patients, the mean fecal toxin concentration was 1,012 ng/g. Toxicity to fibroblasts was demonstrable in filtrates of each of six ELISA-positive samples tested but was absent in all five ELISA-negative samples tested. We conclude that delta-like toxin is elaborated in the bowels of some infants with Tox+ CONS, and its association with NEC suggests that such CONS are enteropathic. In our unit, this mechanism was apparent in 23% of 44 recent cases of endemic NEC.