Immunogenicity and tolerability of inactivated flu vaccine In high risk and healthy children / Inmunogenicidad y tolerancia de la vacuna inactivada anti-influenza en niños en alto riesgo y en controles sanos

We conducted this open study to evaluate the immunogenicity and safety of the inactivated influenza vaccine, Imovax Gripe® in 154 children between 6 and 36 months of age at high risk of influenza- related complications, and in a reference group of 64 healthy children. The study was conducted over two flu seasons, in which the vaccine contained the same A strains but different B strains. The results for the A/H3N2 and A/H1N1 strains from the two flu seasons were pooled, but those for the B strains were not. Anti-hemagglutinin (HA) antibody titers were determined before, and one month after each vaccination, and safety was evaluated based on diary card reporting any adverse event observed, either included or not in the list of "solicited events". Within each group of vaccines, the seroconversion rates, seroprotection rates, and ratio of post- to prevaccination geometric mean titers (GMTR) for the A/H3N2 and the A/H1N1 strains fulfilled all requirements of the criteria of the European Union Committee for Proprietary Medicinal Products (CPMP). The immune responses in high-risk and in healthy children were similar, and consistent with those observed in previous studies conducted in healthy children. The vaccine was equally well tolerated by all study groups. Reactogenicity was low and similar in both high-risk and healthy children. Overall from 9.5% to 15.4% of at-risk children and 12% of healthy children reported a solicited local reaction; 23.0 to 28.8% of high-risk and 25.3% of healthy children reported a solicited systemic reaction. The study results provide support for vaccination of children at high-risk of influenza related complications.

Se realizó un estudio clínico abierto para evaluar la inmunogenícidad y la seguridad de la vacuna inactivada anti-influenza, Imovax Gripe®, en 154 niños entre 6 y 36 meses de edad con alto riesgo de complicaciones ligadas a la influenza, y en un grupo de referencia de 64 niños sanos. El estudio fue conducido en dos temporadas de gripe, durante las cuales la vacuna utilizada contenia las mismas cepas A pero diferentes cepas B. Los resultados para las cepas A/H3N2 y A/H1N1 de las dos temporadas de gripe fueron combinados ( pool de datos), pero no los de las cepas B. Los títulos de anticuerpos anti-hemaglutinina (HA) fueron determinados inmediatamente antes y un mes despues de cada vacunación, y la seguridad o tolerancia fue evaluada según la información de efectos adversos notificados, en cartillas para llenado diario, que incluían todos los eventos, figuraran o no en la lista de los "eventos solicitados". En cada grupo, las tasas de seroconversion y de seroprotección, y la razón de la media geométrica de títulos post-/ pre-vacunación (GMTR) para las cepas A/H3N2 y A/H1N1 cumplieron con todos los requisitos del Comité de Especialidades Farmacéuticas (CPMP) de la Unión Europea. Las respuestas inmunes fueron similares en los niños con alto riesgo y en los sanos, y consistentes con los resultados observados en los estudios anteriores en los niños sanos. La vacuna fue bien tolerada y la reactogenicidad fue baja y similar en los dos grupos de niños estudiados. Las reacciones locales listadas en la solicitud, fueron observadas en el 9.5 a 15.4% y en el 12% de niños con alto riego y sanos respectivamente; mientras que los síntomas sistémicos solicitados fueron observados en el 23.0 a 28.8% y el 25.3% de niños respectivamente. Los resultados de este estudio proveen informatión adicional a favor de la vacunación de niños con alto riesgo de complicaciones relacionadas con influenza.

A randomized controlled trial comparing split and subunit influenza vaccines in adults in Colombia

In a two-center, comparative trial, 344 adults were randomly assigned to receive a single dose of inactivated split-virion (Imovax Gripe) or sub-unit (Agripal S1) influenza vaccine (1999-2000 formulations). For analysis, study groups were subdivided into adult (18-60 years old) and elderly (over 60 years) subjects. Blood was drawn immediately before and one month after vaccination, safety was evaluated using a blind-observer design based on reporting of solicited and unsolicited adverse events. Both vaccines were very well torelated, had similar reactogenicity profiles, and elicited fewer reports of reactions in elderly individuals. Post-vaccination Imovax Gripe induced seroprotective antibody titers against the three vaccine strains in 94-99% of adults and 88-97% od elderly subjects, compared with 88-100% and 88-98%, respectively, of those given Agrippal S1. In conclusion, the split-virion and sub-unit influenza had similar safety and reactogenicity profiles, and elicited satisfactory immunuty in adult and elderly subjects. However, higher post-vaccination geometric mean titer (GMT) values in response to the B strain were seen with the split vaccine Imovax Gripe, giving it a better overall immunogenicity.