Aino Karvonen

Efficacy of human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in European infants: randomised, double-blind controlled study

BACKGROUND We aimed to assess the efficacy of the oral live attenuated human rotavirus vaccine Rotarix (RIX4414) for prevention of rotavirus gastroenteritis in European infants during their first 2 years of life. METHODS 3994 study participants were enrolled from six countries and were randomly assigned two oral doses of either RIX4414 (n=2646) or placebo (n=1348), which were coadministered with the first two doses of specific childhood vaccinations. Follow-up for gastroenteritis episodes was undertaken from 2 weeks post-dose two through the two consecutive rotavirus seasons following vaccinations (combined efficacy follow-up period; mean duration 17 months [SD 1.6]). Our primary endpoint was vaccine efficacy against rotavirus gastroenteritis of any severity during the first efficacy follow-up period (2 weeks post-dose two to the end of the first rotavirus season). Stool specimens obtained during gastroenteritis episodes were tested for rotavirus by ELISA and typed by RT-PCR. Episodes scoring 11 or greater on the 20-point Vesikari scale were classified as severe. Analysis was according to protocol. This study is registered with ClinicalTrials.gov, number NCT00140686 (eTrack102247). FINDINGS 120 infants were excluded from the according-to-protocol analysis. During the first efficacy follow-up period (mean duration 5.7 months [SD 1.2]), 24 of 2572 infants allocated RIX4414 versus 94 of 1302 given placebo had rotavirus gastroenteritis episodes of any severity, resulting in a vaccine efficacy of 87.1% (95% CI 79.6-92.1; p<0.0001). For the combined efficacy follow-up period, vaccine efficacy against severe rotavirus gastroenteritis was 90.4% (85.1-94.1; p<0.0001), for admission owing to rotavirus gastroenteritis 96.0% (83.8-99.5; p<0.0001), and for rotavirus-related medical attention 83.8% (76.8-88.9; p<0.0001), and significant protection against severe rotavirus gastroenteritis by circulating G1, G2, G3, G4, and G9 rotavirus types was shown. INTERPRETATION In a European setting, two doses of RIX4414 coadministered with childhood vaccines provided high protection against any and severe rotavirus gastroenteritis, with an overall reduction of admissions for gastroenteritis over two consecutive rotavirus epidemic seasons.

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 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 (GlaxoSmithKlines 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 ≥0.2 &mgr;g/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 ≥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 (∼6.0–17 fold) and OPA titers (∼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.

Efficacy of RIX4414 live attenuated human rotavirus vaccine in Finnish infants.

Background: Rotavirus gastroenteritis, a major cause of mortality and morbidity worldwide, is a vaccine-preventable disease. New safe and effective candidate rotavirus vaccines are needed to replace the withdrawn rhesus rotavirus-based oral vaccine. Methods: We evaluated a monovalent human rotavirus vaccine, serotype G1, strain RIX4414, for efficacy, immunogenicity and safety in a randomized, double blind, placebo-controlled trial in Finland. We randomly allocated 405 healthy infants to receive 2 doses of vaccine or placebo (ratio 2:1) at ∼2 and 4 months of age. The infants were followed during 2 rotavirus epidemic seasons (2000-2002) for acute gastroenteritis. Rotaviruses in diarrheal stool samples were primarily detected by enzyme-linked immunosorbent assay and confirmed and G-typed by reverse transciption-polymerase chain reaction. Results: The vaccine was well-tolerated. No vaccine-related serious adverse events were observed during the study period. Rotavirus IgA (enzyme-linked immunosorbent assay) seroconversion rate was 80% after 2 doses. Thirty-eight cases of rotavirus gastroenteritis were detected during the entire follow-up period; 35 of these were of the G1 type. RIX4414 vaccine significantly decreased the occurrence of any rotavirus compared with placebo. Efficacy during the first rotavirus epidemic season was 73% [95% confidence interval (95% CI), 27-91%] and 90% (95% CI 10-100%) against any and severe rotavirus gastroenteritis, respectively, and during the entire follow-up period 72% (95% CI 42-87%) against any and 85% (95% CI 42-97%) against severe rotavirus gastroenteritis (P < 0.05 for all comparisons). Conclusions: RIX4414 strain of G1 human rotavirus vaccine was well-tolerated, immunogenic and efficacious in infants against rotavirus gastroenteritis during a 2-year period. To further increase vaccine “take” and efficacy, a higher dose of this vaccine may be considered for future efficacy trials.

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.

MF59®-adjuvanted influenza vaccine (FLUAD®) in children: Safety and immunogenicity following a second year seasonal vaccination

After priming with two intramuscular doses of MF59-adjuvanted (Sub/MF59) or split influenza vaccines during the 2006/07 season, 89 healthy children received a third booster dose of the respective vaccine (2007/08 Northern Hemisphere formulation) approximately 1 year later, and were followed up for 6 months post-third injection. Immunogenicity was evaluated on 81 of them by a hemagglutination inhibition (HI) assay before and 3 weeks after vaccination. The Sub/MF59 influenza vaccine was safe and well tolerated following the booster vaccination. Pre-booster HI antibody titers were consistently higher in the Sub/MF59 group than in the comparator group, confirming significantly longer persistence of antibodies after priming with Sub/MF59 vaccine. Post-booster immune responses were significantly higher in the Sub/MF59 group compared with the split group, especially vs. the influenza B strain, which is epidemiologically relevant in the pediatric population. Altogether, these data further support the potential use of MF59-adjuvanted influenza vaccine as a safe and highly immunogenic influenza vaccine for young children.

A six-fold gradient in the incidence of type 1 diabetes at the eastern border of Finland.

Objective. Type 1 diabetes results from gene‐environment interactions in subjects with genetic susceptibility to the disease. We assessed the contribution of environmental and genetic factors to type 1 diabetes by comparing the incidence in two neighboring populations living in conspicuously different socioeconomic circumstances. Research design and methods. We compared the incidence over a 10‐year period (1990–99) in children younger than 15 years of age living in the Karelian Republic of Russia and in Finland. The frequency of susceptible and protective human leukocyte antigen (HLA)‐DQ alleles was analyzed in 400 non‐diabetic schoolchildren from Russian Karelia and 1000 Finnish subjects. Results. The average annual age‐adjusted incidence of type 1 diabetes was lower in Russian Karelia than in Finland: 7.4 per 100 000 (95% confidence interval 3.5 – 11.3) versus 41.4 per 100 000 (37.3 – 45.5), while there were no differences in the frequency of the HLA DQ genotypes predisposing to type 1 diabetes in the background populations. The incidence rate did not differ significantly between different ethnic groups in Russian Karelia (Finns/Karelians, Russians, others). Conclusions. There is a close to six‐fold gradient in the incidence of type 1 diabetes between Russian Karelia and Finland, although the predisposing HLA DQ genotypes are equally frequent in the two populations. This suggests that environmental factors contribute to this steep difference in the incidence rate between these adjacent regions.

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.

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.