If this is not your name, click here.
| | If this is not your name, click here. | | |
| | Contact Us | Order Now | Journals | Bookstore | Register a colleague | | |
| |  Three H1N1 Vaccine Studies Confirm Doses Needed for Immunogenicity NEW YORK -- December 15, 2009 -- Three studies published early online and appearing in an upcoming issue of The Lancet show that 1 dose of influenza A(H1N1) vaccine should give adults sufficient protection from infection. For children 2 doses could be required. In the first report (from the United States), Martine Denis, MD, Sanofi-Pasteur, Lyon, France, and colleagues looked at the immune response generated by a vaccine approved by the US Food and Drug Administration. In this preliminary report of 2 randomised controlled phase 2 trials, healthy children (aged 6-35 months and 3-9 years) and adults (18-64 years and >= 65 years) were randomised to vaccine containing 7.5 mcg per dose (children and adults), 15 mcg (children and adults), or 30 mcg (adults only) haemagglutinin. The research team assessed 410 of 423 children and 724 of 750 adults given an active vaccine, and 50 of 51 children and 95 of 99 adults given placebo for immunogenicity on day 21. After active vaccination, between 45% (7.5 mcg dose) and 50% (15 mcg) infants aged 6 to 35 months were seroprotected. The corresponding figures for the other age groups were 69% (7.5 mcg) to 75% (15 mcg) for children aged 3 to 9 years; 95% (7.5 mcg) to 100% (30 mcg) for adults aged 18 to 64 years; and 93% (15 mcg) to 95% (30 mcg) for adults aged 65 years and older. No vaccine-related serious adverse events occurred. Injection-site and systemic reactions were reported by up to about 50% of every age and vaccine group, with no noticeable differences between vaccine and placebo groups. “One dose of vaccine was highly immunogenic in adults, suggesting that it afforded sufficient protection against the H1N1 virus,” the authors wrote. “Two doses of vaccine will probably be needed in children younger than 9 years. Safety and reactogenicity of the vaccine were acceptable and similar to those of seasonal vaccine.” In the second article (from China) Yu Wang, MD, Chinese Centre for Disease Control and Prevention, Beijing, China, and colleagues conducted a multicentre, randomised, placebo-controlled study in 12 691 people aged 3 years or older, assessing 8 vaccine formulations. The research team found that seroprotection rates varied from 70% to 93% depending on the formulation used (with the 30 mcg non-adjuvant formula giving the best protection). As with the US study, the 7.5 mcg, non-adjuvant formula offered substantial seroprotection, with 87% across all age groups protected (vs 10% for placebo). In terms of individual age groups, the 7.5 mcg formulation induced seroprotection in 77% of children aged 3 to 12 years; 97% of adolescents aged 12 to 18 years; 90% of adults aged 18 to 60 years; and 80% of adults aged over 60 years. In children aged 3 to 12 years, a second dose of the same 7.5 mcg formulation increased seroprotection rates to 98%. Adverse reactions were mostly mild or moderate, and self-limited. Severe adverse events occurred in 69 (0.6%) recipients of vaccine compared with 1 recipient (0.1%) of placebo. The most common severe adverse reaction was fever, which occurred in 25 (0.22%) recipients of vaccine after the first dose and in 4 (0.04%) recipients of vaccine after the second dose compared with no recipients of placebo after either dose. “We recommend that non-adjuvant split-virion vaccine containing 7.5 mcg haemagglutinin is adopted as the vaccine of choice against H1N1 in adolescents and adults,” the authors concluded. “A 2-dose schedule of this formulation might be needed in children.” In the third article (from Hungary) Zoltan Vajo, MD, University of Debrecen, Debrecen, Hungary, and colleagues looked at administration of a H1N1 vaccine both alone and together with a seasonal influenza vaccine. A total of 355 participants, including 203 adults (aged 18-60 years) and 152 elderly people (aged >60 years), were randomly assigned to either 0.5 mL of a monovalent HIN1 vaccine with 6 mcg haemagglutinin per 0.5 mL and aluminium phosphate gel adjuvant (n = 178; group 1) or 0.5 mL of same H1N1 vaccine plus 0.5 mL of a trivalent seasonal influenza vaccine (n = 177 recipients; group 2). Participants in both groups developed antibody responses against H1N1. In group 1, seroprotection rate for adults was 74%, and 61% for elders. In group 2, rates were 76.8% and 81.8%, respectively. Single doses of 6 mcg fulfilled European Union and US licensing criteria for both the combined and H1N1 only vaccines. Simultaneously, participants in group 2 developed the immune responses needed for licensing for all 3 strains in the seasonal vaccine for the 2009-10 season. All adverse events were rare, mild, and transient; the most frequent were pain at injection site (8 in group 1 vs 18 in group 2) and fatigue for 1 to 2 days after vaccination (3 vs 5). “The present pandemic vaccine is safe and immunogenic in healthy adult and elderly patients, and needs low doses and only 1 injection to trigger immune responses to comply with licensing criteria,” the authors wrote. “It can be safely co-administered with the 2009-10 seasonal influenza vaccine.” SOURCE: The Lancet
|
