Oil-in-water emulsion adjuvant with influenza vaccine in young children.

BACKGROUND: The efficacy of inactivated influenza vaccines is known to be poor in infants and young children. METHODS: We studied the effect of the adjuvant MF59, an oil-in-water emulsion, on the efficacy of trivalent inactivated influenza vaccine (TIV) in 4707 healthy children 6 to less than 72 months of age who had not previously been vaccinated against influenza. The children were randomly assigned to three study groups, each of which received the assigned vaccines in two doses, 28 days apart, during two consecutive influenza seasons. Two of the groups were given age-appropriate doses of TIV either with or without the MF59 adjuvant, and the third group was given control (noninfluenza) vaccines to assess their absolute and relative efficacy against influenza-like illness, as confirmed by means of polymerase-chain-reaction (PCR) assay. RESULTS: Attack rates of influenza-like illness across both influenza seasons were 0.7%, 2.8%, and 4.7% in the adjuvant, nonadjuvant, and control vaccine groups, respectively. The absolute vaccine efficacy rates against all influenza strains (94 of 110 cases were due to vaccine-matched H3N2 viruses) were 86% (95% confidence interval [CI], 74 to 93) for the MF59-adjuvant vaccine (ATIV) and 43% (95% CI, 15 to 61) for the vaccine without the adjuvant (TIV); the relative vaccine efficacy rate for ATIV versus TIV was 75% (95% CI, 55 to 87). The efficacy rates for ATIV were 79% (95% CI, 55 to 90) in children 6 to less than 36 months of age and 92% (95% CI, 77 to 97) in those 36 to less than 72 months of age, as compared with 40% (95% CI, -6 to 66) and 45% (95% CI, 6 to 68), respectively, for TIV. Antibody responses were higher with ATIV and remained so through day 181. The rates of systemic and local reactions to the influenza vaccines with and without the adjuvant were similar in the younger age group (relative risk, 1.04; 95% CI, 0.98 to 1.09), but systemic events in the older age group were more frequent after administration of ATIV (63%) than after administration of TIV (44%) or the control vaccine (50%). Serious adverse events were distributed evenly across the three vaccine groups. CONCLUSIONS: Influenza vaccine with the MF59 adjuvant is efficacious against PCR-confirmed influenza in infants and young children. (Funded by Novartis Vaccines and Diagnostics; ClinicalTrials.gov number, NCT00644059.).

Immunogenicity of 10-valent pneumococcal nontypeable Haemophilus Influenzae Protein D Conjugate Vaccine when administered as catch-up vaccination to children 7 months to 5 years of age.

BACKGROUND: We evaluated catch-up vaccination schedules with 10-valent pneumococcal nontypeable Haemophilus influenzae Protein D Conjugate Vaccine (PHiD-CV). METHODS: In this open, controlled study, children stratified into 4 age groups (N = 150 each) were vaccinated with PHiD-CV: (a) <6 months reference group: 3 primary doses with booster at 12 to 15 months, (b) 7 to 11 months: 2 doses and booster at 12 to 15 months, (c) 12 to 23 months: 2 doses, and (d) 2 to 5 years: 1 dose. Serotype-specific pneumococcal responses were measured by 22F-inhibition enzyme-linked immunosorbent assay (ELISA) and opsonophagocytic activity (OPA) assay. RESULTS: In the 7 to 11 months group postbooster antibody geometric mean concentrations (except for 2 serotypes) and OPA geometric mean titers (GMTs) were in the same ranges or higher relative to postbooster values in the <6 months reference group. Following 2 doses in the 12 to 23 months group, the percentages reaching threshold levels for ELISA (except for serotypes 6B and 23F) and OPA (except for serotype 1) were comparable or higher than <6 months reference postbooster values. Antibody geometric mean concentrations and OPA GMTs, while comparable or higher than reference postprimary values, were for some serotypes lower than reference postbooster values. Following 1 dose in the 2 to 5 years group ELISA responses were lower than the reference group for several serotypes. CONCLUSIONS: A catch-up PHiD-CV schedule of 2 doses and booster for children 7 to 11 months of age was acceptable. For children 12 to 23 months of age, 2 doses seem to provide adequate priming although a booster dose might confer further benefit. Responses following 1 dose in children 2 to 5 years of age suggest that 2 doses may be preferable.

Results from a randomized clinical trial of coadministration of RotaTeq, a pentavalent rotavirus vaccine, and NeisVac-C, a meningococcal serogroup C conjugate vaccine.

RotaTeq (Merck & Co. Inc./Sanofi Pasteur MSD) is a three-dose, oral pentavalent rotavirus vaccine for the immunization of infants from 6 weeks of age for the prevention of rotavirus gastroenteritis. The primary objective of the present trial was to demonstrate that RotaTeq can be coadministered with meningococcal serogroup C conjugate vaccine (MenCC; NeisVac-C; Baxter Healthcare) to healthy infants without impairing the protective immune responses to MenCC. This was an open-label, randomized, comparative study conducted in Finland. The study was designed to assess concomitant versus sequential administration of RotaTeq and MenCC on the immune response to both vaccines. Healthy infants (n = 247), aged 6 to 7 weeks, were recruited. Coadministration of MenCC with RotaTeq was noninferior to sequential administration for the seroprotection rate against meningococcal serogroup C (the proportion of infants with a serum bactericidal antibody titer using baby rabbit complement of ≥ 8 was 100% in both groups). The other responses to MenCC (titer of ≥ 1:128, ≥ 4-fold increase in titer, and geometric mean titers [GMTs]) and the responses to RotaTeq (IgA and SNA response to G1 to G4 and P1A[8], GMTs, and ≥ 3-fold increase in titer) were comparable between groups, including a ≥ 3-fold IgA increase in >96% of the infants in both groups. Concomitant administration of the first doses of MenCC, diphtheria and tetanus toxoids and acellular pertussis vaccine, inactivated poliovirus vaccine, and Haemophilus influenzae type b conjugate vaccine (DTaP-IPV-Hib), and RotaTeq was associated with a higher rate of vomiting and diarrhea than concomitant administration of MenCC and DTaP-IPV-Hib, but that was not observed after the second concomitant administration. The convenience of concomitant administration of RotaTeq and MenCC may, however, outweigh the additive effect of mostly mild adverse events reported after the individual administration of each vaccine. These results support the coadministration of RotaTeq and MenCC.

Tetravalent meningococcal serogroups A, C, W-135 and Y conjugate vaccine is well tolerated and immunogenic when co-administered with measles-mumps-rubella-varicella vaccine during the second year of life: An open, randomized controlled trial.

Co-administration of meningococcal ACWY-tetanus toxoid conjugate vaccine (ACWY-TT) with MMRV vaccine was investigated in 1000 12-23-month old children randomized (3:3:1:1) to receive co-administered ACWY-TT+MMRV, or a single dose of ACWY-TT, MMRV or MenC-CRM(197). Non-inferiority of ACWY-TT to MenC-CRM(197) and non-inferiority of ACWY-TT+MMRV to ACWY-TT and MMRV alone, and the immunogenicity of serogroups AWY were demonstrated according to pre-defined criteria. Fever reactions in ACWY+MMRV and MMRV groups were comparable. ACWY-TT can be co-administered with MMRV without affecting immunogenicity or safety profiles of either vaccine. This study has been registered at www.clinicaltrials.gov NCT00474266.

Immunogenicity and safety of MF59-adjuvanted H5N1 influenza vaccine from infancy to adolescence.

OBJECTIVE: This study evaluated the immunogenicity, safety, and tolerability of a MF59-adjuvanted H5N1 vaccine in a population 6 months through 17 years of age. METHODS: Healthy subjects 6 to <36 months, 3 to <9 months, and 9 to <18 years of age were assigned randomly to receive 2 doses of either a MF59-adjuvanted H5N1 vaccine (7.5 µg/dose) or a MF59-adjuvanted trivalent seasonal influenza control vaccine (15 µg/dose for each antigen). Immunogenicity against the A/Vietnam/1194/2004-like vaccine strain was measured before and 3 weeks after the 2-dose primary series, through hemagglutination inhibition (HI), single radial hemolysis (SRH), and microneutralization. Local and systemic reactions were recorded. RESULTS: A total of 335 subjects received the H5N1 vaccine, and 137 subjects received the seasonal vaccine. Rates of seroprotection (HI titer of ≥40) against the H5N1 vaccine antigen were 97% for children 6 to 36 months and 3 to 9 years of age and 89% for older children. All subjects seroconverted in the SRH assay. Microneutralization titers of ≥40 were achieved by 99% of subjects, and ≥98% of subjects, respectively. Local reactions, particularly injection site pain in older children, were common, generally mild to moderate in nature, and transient and resolved spontaneously. Up to 5% of participants. There were no vaccine-related serious adverse events in either group. CONCLUSIONS: In this pediatric population, MF59-adjuvanted H5N1 vaccine was highly immunogenic, had a good safety profile, reactogenicity comparable with that of an adjuvanted seasonal influenza control vaccine.

Norovirus gastroenteritis in young children receiving human rotavirus vaccine.

We explored whether human rotavirus vaccine had any efficacy against norovirus (NV)-associated gastroenteritis in young children. In an efficacy trial of rotavirus vaccine, 405 infants were immunized with a human rotavirus vaccine or placebo at a ratio of 2:1, and prospectively followed for acute gastroenteritis (AGE) from approximately 2 months to 2 y of age. Multiplex real-time reverse transcription polymerase chain reaction (Mrt RT-PCR) assays were used for detection and quantitation of NVs of genogroup I (GI) and genogroup II (GII) in stool specimens. NVs were detected in 155 (32%) of 485 episodes of AGE. Of these, NV was the only gastroenteritis virus detected in the stools in 142 (29%) episodes. GI and GII NVs were found in 12% and 88% of the cases, respectively. NV as the only gastroenteritis virus was detected in 36% of the infants in the rotavirus vaccine group and 27% in the placebo group. The clinical severity of NV-associated AGE in the vaccine and placebo recipients was not different. NVs were the most common etiologic agents of AGE in children under 2 y of age. Human rotavirus vaccine did not protect against NV gastroenteritis.

Efficacy of the pentavalent rotavirus vaccine, RotaTeq®, in Finnish infants up to 3 years of age: the Finnish Extension Study.

Rotavirus Efficacy and Safety Trial (REST) enrolled nearly 70,000 infants, of whom more than 23,000 were from Finland. REST determined the efficacy of the pentavalent rotavirus vaccine (RV5) against rotavirus-related hospitalisations and emergency department (ED) visits in the first year after vaccination. Finnish infants initially in REST transitioned into the Finnish Extension Study (FES), where they were followed for rotavirus-related hospitalisations and ED visits through their second year of life and beyond. FES identified 150 (31%) additional rotavirus gastroenteritis (RVGE) cases beyond those identified in REST in the Finnish participants. Overall, RV5 reduced RVGE hospitalisations and ED visits, regardless of the rotavirus serotype, by 93.8% (95% confidence interval [CI]: 90.8-95.9%) for up to 3.1 years following the last vaccine dose. Vaccine efficacy against combined hospitalisations and ED visits between ages 4 months to 11 months, 12 months to 23 months, and 24 months to 35 months was 93.9% (95% CI: 89.1-96.9%), 94.4% (95% CI: 90.2-97.0%), and 85.9% (95% CI: 51.6-97.2%), respectively. The reduction of hospitalisations and ED visits due to any acute gastroenteritis, rotavirus or not, was 62.4% (95% CI: 57.6-66.6%) over the entire follow-up period. The results from FES confirm that RV5 induces high and sustained protection against rotavirus-related hospitalisations and ED visits, and has a very substantial impact on all gastroenteritis-related hospitalisations and ED visits into the third year of life in Finnish children.

Immunogenicity and safety of the human rotavirus vaccine Rotarix co-administered with routine infant vaccines following the vaccination schedules in Europe.

This study assessed the immunogenicity and safety of a human rotavirus vaccine RIX4414; the effect of co-administration of childhood vaccines on the immune responses was also assessed. Healthy infants aged 6-14 weeks received two doses of RIX4414/placebo concomitantly with the primary childhood vaccination (Infanrix hexa, Infanrix quinta,Meningitec and/or Prevnar), respecting the vaccination schedule of each country. Anti-rotavirus IgA seroconversion rate (ELISA cut-off 20 U/ml) was measured pre-vaccination and 1-2 months post-Dose 2. Immune response against diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b, inactivated polio virus, pneumococcal polysaccharide conjugate (France and Germany) and meningococcal group C conjugate vaccines (Spain) were measured approximately 1-month post-Dose 3. An overall anti-rotavirus IgA seroconversion rate of 86.5%(95% CI: 83.9-88.8) was observed in the RIX4414 group 1-month post-Dose 2. The seroconversion rate in Finland and Italy (3 and 5-month schedule) was 94.6%(95% CI: 90.0-97.5) and 92.3%(95% CI: 64.0-99.8), respectively. Immune response to the childhood vaccines was unaffected following co-administration with RIX4414. Reactogenicity profile was similar for RIX4414 and placebo groups. RIX4414 was immunogenic and well tolerated in European infants and the co-administration of routine childhood vaccines with RIX4414 did not negatively impact the immune responses to these vaccines.

Safety and immunogenicity of a booster dose of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine coadministered with measles-mumps-rubella-varicella vaccine in children aged 12 to 16 months.

BACKGROUND: A booster dose of pneumococcal conjugate vaccine may be administered at the same age as measles-mumps-rubella-varicella (MMRV) vaccination. This study examined the safety, reactogenicity, and immunogenicity of a booster dose of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) when coadministered with MMRV vaccine. METHODS: In this open, controlled study, 325 healthy children aged 12 to 14 months were randomized to 1 of 3 groups: the first group (N = 110) received PHiD-CV and MMRV vaccine followed 6 to 8 weeks later by MMRV and DTPa-HBV-IPV/Hib vaccines; the second group (N = 101) received DTPa-HBV-IPV/Hib and MMRV vaccines followed 6 to 8 weeks later by PHiD-CV and MMRV vaccine; the third group (N = 114) received PHiD-CV and DTPa-HBV-IPV/Hib vaccine during 1 vaccination visit. Immune responses were assessed with GlaxoSmithKline's 22F-inhibition enzyme-linked immunosorbent assay (for PHiD-CV), commercial enzyme-linked immunosorbent assay (for MMR), or indirect immunofluorescence assay (for varicella). Adverse events were recorded by the parents/guardians. RESULTS: After the first vaccination, 2 peaks in fever (rectal temperature > or =38 degrees C) were observed; at days 0 to 2, related to PHiD-CV and DTPa-HBV-IPV/Hib vaccination, and at days 4 to 12, related to MMRV vaccination. Booster responses to pneumococcal antigens and protein D and seroconversion rates for all MMRV vaccine components were high. CONCLUSIONS: PHiD-CV and MMRV vaccine can be coadministered without compromising the safety and immunogenicity profiles of either vaccine.

Sustained efficacy of the pentavalent rotavirus vaccine, RV5, up to 3.1 years following the last dose of vaccine.

BACKGROUND: Rotavirus gastroenteritis (RVGE) is a common cause of childhood hospitalizations and emergency department (ED) visits. In the Rotavirus Efficacy and Safety Trial (REST), the pentavalent rotavirus vaccine (RV5) significantly reduced RVGE-associated hospitalizations and ED visits for up to 2 years following the last vaccine dose. This study evaluated whether RV5 remained efficacious beyond 2 years. METHODS: A total of 20,736 infants from Finland, initially in REST, were followed for RVGE-associated hospitalizations and ED visits in a Finnish extension study (FES) for up to 3.1 years after vaccination (age, ∼3.5 years). RESULTS: The FES added >18,500 person-years and captured 150 RVGE-associated hospitalizations and ED visits (11 RV5; 139 placebo). In REST + FES, RV5 reduced RVGE-associated hospitalizations and ED visits, regardless of rotavirus serotype, by 94.0% (95% confidence interval [CI]: 91.4%-95.9%) for up to 3.1 years after vaccination. RV5 also conferred significant protection against hospitalizations and ED visits associated with rotavirus serotypes G1 (95.5%; 95% CI: 92.8%-97.2%), G2 (81.9%; 95% CI: 16.1%-98.0%), G3 (89.0%; 95% CI: 53.3%-98.7%), G4 (83.4%; 95% CI: 51.2%-95.8%), and G9 (94.2%; 95% CI: 62.2%-99.9%). Rate reductions (95% CI) in hospitalizations and ED visits during the first, second, and third years of life were 94.0% (90.0%-96.5%), 94.7% (90.7%-97.2%), and 85.9% (51.6%-97.2%), respectively. CONCLUSIONS: RVGE-associated hospitalizations and ED visits remain common in the second year of life but decrease in the third year of life. RV5 showed sustained protective efficacy against RVGE-associated hospitalizations and ED visits, regardless of rotavirus serotype, for up to 3.1 years after vaccination.

RotaTeq, a pentavalent rotavirus vaccine: efficacy and safety among infants in Europe.

A pentavalent human-bovine reassortant oral rotavirus vaccine, RotaTeq, was evaluated among nearly 70,000 infants in the Rotavirus Efficacy and Safety Trial (REST), of which 30,523 were from Europe. All infants were followed for serious adverse events as well as hospitalizations and emergency department (ED) visits. All adverse events, health care utilization, and RVGE regardless of severity were evaluated in the clinical efficacy cohort (N=2686) in Finland. RotaTeq was 98.3% (95% CI, 90.2-100%) and 68.0% (95% CI 60.3-74.4%) efficacious against severe rotavirus gastroenteritis (RVGE) and all RVGE due to any serotype for two rotavirus seasons post-vaccination. The combined rate of hospitalizations and ED visits due to RVGE of any serotype was reduced by 94.5% (95% CI, 91.3-96.8%) for up to 2 years after vaccination. There were no statistically significant differences between RotaTeq and placebo for any of the safety outcomes. In Europe, RotaTeq was highly efficacious and well tolerated.

Efficacy of inactivated split-virus influenza vaccine against culture-confirmed influenza in healthy adults: a prospective, randomized, placebo-controlled trial.

BACKGROUND: A new trivalent inactivated split-virus influenza vaccine (TIV) was recently introduced in the United States. We assessed the efficacy of TIV against culture-confirmed influenza A and/or B. METHODS: In this double-blind trial conducted from September 2006 to May 2007 in the Czech Republic and Finland, participants aged 18-64 years were randomized to receive 1 dose of TIV (n = 5103) or placebo (n = 2549). Influenza-like illnesses (ILI) (defined as at least 1 systemic symptom [fever {oral temperature, > or = 37.8 degrees C} and/or myalgia] and at least 1 respiratory symptom [cough and/or sore throat]) were identified by both active (biweekly phone contact) and passive surveillance. Nasal and throat swab specimens were collected for viral culture. RESULTS: The attack rate for culture-confirmed ILI was 3.2% in the placebo group, with most strains identified as influenza A (all except 1 were H3N2) matching the vaccine strain. There were 6 cases of influenza B, all of which were of a different lineage (Yamagata) than the vaccine strain. Vaccine efficacy against culture-confirmed influenza A and/or B due to strains antigenically matched to the vaccine was 66.9% (95% confidence interval [CI], 51.9%-77.4%; P < .001) and to any strain was 61.6% (95% CI, 46.0%-72.8%; P < .001). CONCLUSION: TIV is efficacious against culture-confirmed influenza in healthy adults. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00363870.

Enhanced immunogenicity of seasonal influenza vaccines in young children using MF59 adjuvant.

BACKGROUND: Children have high morbidity and hospitalization rates from seasonal influenza. Meta-analyses suggest that conventional inactivated influenza vaccines are of low efficacy in young children, making vaccines that induce greater and broader immune protection in this vulnerable population a medical priority. Adjuvanted influenza vaccines may offer a solution. SUBJECTS AND METHODS: Unprimed healthy children (6 to <36 months) were enrolled in an observer-blinded study and randomly assigned to receive 2 doses of MF59-adjuvanted vaccine (Sub/MF59, n = 130) or nonadjuvanted split vaccine (split, n = 139); subgroups of these (n = 43 and 46, respectively) received a booster dose 1 year later. Safety and clinical tolerability were assessed after each dose. Hemagglutination inhibition antibody titers were measured against influenza A and B strains included in the formulation of the vaccines and against mismatched strains. RESULTS: Clinical tolerability and safety were generally comparable between vaccine groups, though some transient, mild solicited reactions were more frequent in the Sub/MF59 group. Postvaccination hemagglutination inhibition antibody titers to all 3 vaccine strains were significantly higher with Sub/MF59 than with split vaccine (all comparisons P < 0.001) after each of the 3 vaccine doses. In addition, Sub/MF59 induced significantly higher cross-reactivity against A/H3N2 and A/H1N1 mismatched strains. CONCLUSION: MF59-adjuvanted influenza vaccine was well tolerated in healthy young children after each of 3 doses and induced greater, longer-lasting, and broader immune responses than a nonadjuvanted split vaccine. The enhanced immunogenicity of the adjuvanted vaccine was most evident in very young children and for the B vaccine strain.

Immunogenicity of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) compared to the licensed 7vCRM vaccine.

BACKGROUND: The immunogenicity of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) was assessed and compared with the 7-valent pneumococcal conjugate vaccine (7vCRM). METHODS: Healthy subjects (1650) were randomized to be vaccinated with 3 doses of PHiD-CV or 7vCRM (Prevenar/Prevnar) at 2-3-4 months of age and a fourth booster dose at 12-18 months. Serotype-specific pneumococcal responses (GlaxoSmithKline's ELISA with 22F-inhibition) and opsonophagocytic activity (OPA) were measured 1 month after primary and booster vaccinations. RESULTS: The primary objective to demonstrate noninferiority of PHiD-CV versus 7vCRM (in terms of percentage of subjects with antibody concentration >or=0.2 microg/mL) for at least 7 of the 10 vaccine serotypes was reached as noninferiority was demonstrated for 8 serotypes. Although, noninferiority could not be demonstrated for ELISA responses against serotypes 6B and 23F, a post-hoc analysis of the percentage of subjects with OPA titers >or=8 suggested noninferiority for the 7 serotypes common to both vaccines including 6B and 23F.Priming of the immune system against all vaccine serotypes was confirmed by robust increases in ELISA antibody levels ( approximately 6.0-17 fold) and OPA titers ( approximately 8-93 fold) after a fourth consecutive dose of PHiD-CV. CONCLUSIONS: PHiD-CV induces ELISA and functional OPA antibodies for all vaccine serotypes after primary vaccination and is noninferior to 7vCRM in terms of ELISA and/or OPA threshold responses. Effective priming is further indicated by robust booster responses.

Safety and tolerability of cold-adapted influenza vaccine, trivalent, in infants younger than 6 months of age.

OBJECTIVE: Young children are at high risk for influenza-related complications. Vaccination of close household contacts is recommended to provide indirect protection to children <6 months of age. Studies have shown that live, cold-adapted influenza vaccine, trivalent, is efficacious in children. To assess the risks associated with inadvertent exposure of infants to vaccine viruses from vaccinated contacts, this study was designed to evaluate the safety and tolerability of cold-adapted influenza vaccine, trivalent, administered intranasally to healthy children 6 to <24 weeks of age. METHODS: Healthy infants aged 6 to <16 weeks and 16 to <24 weeks, respectively, were randomly assigned to receive 2 doses of influenza vaccine, or placebo intranasally 35 +/- 7 days apart. Reactogenicity events were monitored for 11 days after each dose. Other adverse events were monitored through 28 to 35 days after dose 2. RESULTS: Of the infants aged 6 to <16 weeks, 31 received influenza vaccine and 28 received placebo, and of those aged 16 to <24 weeks, 30 received influenza vaccine and 31 received placebo. In the 6- to <16-week cohort, more influenza vaccine, recipients experienced irritability (66.7% vs 35.7%) and runny nose or nasal congestion (63.3% vs 33.3%) after dose 1 but not dose 2. There were no significant increases in any other reactogenicity events or adverse events in the vaccine recipients compared with the placebo group. CONCLUSIONS: Although there was an increase in mild reactogenicity events in children 6 to <16 weeks of age, cold-adapted influenza vaccine, trivalent, was generally well tolerated in infants 6 to <24 weeks of age. These findings support further evaluation of cold-adapted influenza vaccine, trivalent, in infants <6 months of age.

Safety, efficacy, and immunogenicity of 2 doses of bovine-human (UK) and rhesus-rhesus-human rotavirus reassortant tetravalent vaccines in Finnish children.

BACKGROUND: Live oral rhesus-rhesus-human rotavirus reassortant tetravalent (RRV-TV) vaccine was efficacious against rotavirus gastroenteritis but was withdrawn because of a rare association with intussusception. A corresponding tetravalent (types G1, G2, G3, and G4) reassortant vaccine based on bovine-human (UK) rotavirus reassortant tetravalent (BRV-TV) vaccine was developed concurrently. METHODS: Before the withdrawal of RRV-TV vaccine, parallel placebo-controlled trials of BRV-TV vaccine (observer blinded) versus RRV-TV vaccine (double blinded) with a 2 : 1 ratio of vaccine : placebo were conducted in Finland in a total of 510 infants. Two doses of study vaccine or placebo were administered at ages 3 and 5 months. RESULTS: The first dose of RRV-TV vaccine was followed by a significant excess rate of febrile reactions (36%), whereas the rate of fever after the administration of BRV-TV vaccine did not differ significantly from that in the placebo group. Neither vaccine induced diarrhea. A seroresponse was detected in 97% of BRV-TV vaccine recipients and 94% of RRV-TV vaccine recipients. Both vaccines were equally effective, with 68%-69% efficacy against any and 88%-100% efficacy against severe rotavirus gastroenteritis during the first epidemic season. CONCLUSIONS: BRV-TV vaccine is a promising new candidate rotavirus vaccine, with low reactogenicity and high efficacy. Two doses of BRV-TV or RRV-TV vaccine are sufficient for the induction of protection against severe rotavirus disease.

A randomized, double-blind study of the safety, transmissibility and phenotypic and genotypic stability of cold-adapted influenza virus vaccine.

BACKGROUND: Live attenuated influenza vaccine (LAIV; FluMist) is a trivalent vaccine containing cold-adapted influenza vaccine viruses that infect and replicate in cells lining the nasopharynx to induce immunity. Recovery of viruses (shedding) is measured by culture of nasal specimens. Shedding of vaccine viruses is not equated with transmission because transmission requires more virus than is detected in many nasal swabs. Previous studies with LAIV did not detect transmission to close contacts. The primary objective of this study was to estimate the probability of transmission to placebo contacts in a day care setting. METHODS: One hundred ninety-seven healthy children aged 9 to 36 months attending day care were randomized to receive vaccine or placebo. Postvaccination viral shedding, safety, genotype and phenotype of shed viruses and probability of transmission were assessed. RESULTS: Eighty percent of 98 vaccine recipients shed at least one vaccine strain. No clinically significant differences in solicited adverse events attributable to vaccine occurred; safety profiles were similar in both groups. Vaccine virus isolates retained their phenotypic characteristics (cold adaptation and temperature sensitivity) and did not revert at nucleotides known to confer an attenuating phenotype. There was one confirmed transmission of a vaccine strain to a single placebo recipient. According to the Reed-Frost model, the calculated probability of transmission to a child after contact with a single vaccinated child was 0.58% (95% confidence interval, 0-1.7%). There was no increased reactogenicity or other safety concerns in the recipient child. CONCLUSIONS: Young children in a day care setting had a high rate of shedding and a low rate of transmission. No clinically significant illness occurred among children who received vaccine or placebo or in the child to whom the vaccine virus was transmitted.

Effects of the potency and composition of the multivalent human-bovine (WC3) reassortant rotavirus vaccine on efficacy, safety and immunogenicity in healthy infants.

BACKGROUND: Rotavirus gastroenteritis, which causes substantial infant mortality and morbidity worldwide, is a vaccine-preventable disease. The purpose of this study was to evaluate different compositions and potencies (vaccine virus titers) of a live multivalent human-bovine (WC3) reassortant rotavirus vaccine in order to select the potency and composition of the vaccine for further development. METHODS: The efficacy, safety, and immunogenicity of a G1, G2, G3, G4, and P1A pentavalent composition at three different potencies, a G1, G2, G3, G4 quadrivalent composition, and a P1A monovalent composition of an oral human-bovine (WC3) reassortant rotavirus vaccine were compared in a blinded, placebo-controlled trial conducted between 1998 and 2001 enrolling 1,946 healthy Finnish infants 2-8 months of age. RESULTS: All potencies of the pentavalent and quadrivalent vaccines were efficacious (58-74%) against wild-type rotavirus gastroenteritis of any severity and 100% protective against severe rotavirus disease caused by vaccine G-serotypes through the first rotavirus season post-vaccination. The monovalent P1A vaccine was 53% efficacious against moderate-and-severe rotavirus gastroenteritis. Protection against rotavirus gastroenteritis of any severity was demonstrated through two and three rotavirus seasons for all vaccine compositions. After the third dose, the percentage of infants with >or=3-fold rise in baseline serum neutralizing antibody titers against G1 ranged from 62% to 86% for recipients of the pentavalent vaccine, depending on the potency. The incidence of fever, irritability, vomiting, and diarrhea did not significantly differ between vaccine and placebo groups. A 7-month-old male developed intussusception 9 days after the first dose of the low-potency pentavalent vaccine. CONCLUSIONS: Based on the results of this trial, a pentavalent composition (G1, G2, G3, G4, and P1A) of human-bovine (WC3) reassortant rotavirus vaccine with a potency similar to that of the middle-potency pentavalent vaccine ( approximately 8 x 10(6) plaque-forming units/dose) was selected for further development.

Neonatal administration of rhesus rotavirus tetravalent vaccine.

BACKGROUND AND AIMS: Administration of the first dose of rhesus rotavirus-based tetravalent (RRV-TV) vaccine is followed by a transient febrile reaction at 3-4 days postvaccination in about one-third of vaccinees. We hypothesized that giving the first dose of RRV-TV vaccine during the neonatal period might reduce the reactogenicity of RRV-TV vaccine without compromising the utilization of the vaccine. METHODS: A double blind placebo-controlled safety and immunogenicity trial of 90 infants who received RRV-TV vaccine at 0-4-6, 0-2-4 or 2-4-6 months of age was conducted. Reactions were evaluated for 1 week after each vaccination and, in addition, serum specimens were collected before vaccination and at 5 and 7 months of age. RESULTS: Febrile reactions were not observed in 62 infants receiving the first dose of RRV-TV vaccine during the neonatal period. Five of the 28 (18%) infants receiving the first dose at 2 months were febrile on 1 or more days, whereas none of the 30 infants who had received a neonatal dose developed a fever when vaccinated again at 2 months of age. An enzyme-linked immunosorbent assay IgA antibody response after 3 doses was observed significantly less frequently (77%) in infants who had received a neonatal dose, a second dose at 2 months of age, and a third dose at 4 months of age compared with those who received their first dose at 2 months and a second dose at 4 months (100%, P < 0.02). Also, the frequency of a neutralizing antibody response to RRV and human rotavirus serotypes G1-4 tended to be lower in the group that had received the vaccine at 0-2-4 months compared with those who received it at 2-4-6 months. When the 2 tests were combined, the frequency of a seroresponse following the 0-2-4 month schedule (94%) was comparable with that following the 2-4-6 month schedule (100%). CONCLUSION: Infants who received the first dose of RRV-TV vaccine during the neonatal period did not develop a febrile reaction. The immune response in a 3-dose schedule initiated in the neonatal period is somewhat dampened but still acceptable. Neonatal immunization might also reduce the very small risk of intussusception, which has been associated with administration of RRV-TV vaccine to older infants.

Safety and efficacy of a pentavalent human-bovine (WC3) reassortant rotavirus vaccine.

BACKGROUND: Rotavirus is a leading cause of childhood gastroenteritis and death worldwide. METHODS: We studied healthy infants approximately 6 to 12 weeks old who were randomly assigned to receive three oral doses of live pentavalent human-bovine (WC3 strain) reassortant rotavirus vaccine containing human serotypes G1, G2, G3, G4, and P[8] or placebo at 4-to-10-week intervals in a blinded fashion. Active surveillance was used to identify subjects with serious adverse and other events. RESULTS: The 34,035 infants in the vaccine group and 34,003 in the placebo group were monitored for serious adverse events. Intussusception occurred in 12 vaccine recipients and 15 placebo recipients within one year after the first dose including six vaccine recipients and five placebo recipients within 42 days after any dose (relative risk, 1.6; 95 percent confidence interval, 0.4 to 6.4). The vaccine reduced hospitalizations and emergency department visits related to G1-G4 rotavirus gastroenteritis occurring 14 or more days after the third dose by 94.5 percent (95 percent confidence interval, 91.2 to 96.6 percent). In a nested substudy, efficacy against any G1-G4 rotavirus gastroenteritis through the first full rotavirus season after vaccination was 74.0 percent (95 percent confidence interval, 66.8 to 79.9 percent); efficacy against severe gastroenteritis was 98.0 percent (95 percent confidence interval, 88.3 to 100 percent). The vaccine reduced clinic visits for G1-G4 rotavirus gastroenteritis by 86.0 percent (95 percent confidence interval, 73.9 to 92.5 percent). CONCLUSIONS: This vaccine was efficacious in preventing rotavirus gastroenteritis, decreasing severe disease and health care contacts. The risk of intussusception was similar in vaccine and placebo recipients. (ClinicalTrials.gov number, NCT00090233.)