Live Attenuated Influenza Vaccine (FluMist®; Fluenz™)

Abstract

Live attenuated influenza vaccine (LAIV) is an intranasally administered trivalent, seasonal influenza vaccine that contains three live influenza viruses (two type A [H1N1 and H3N2 subtypes] and one type B). LAIV was effective in protecting against culture-confirmed influenza caused by antigenically matched and/or distinct viral strains in children aged ≤71 months enrolled in three phase III trials. LAIV was superior to trivalent inactivated influenza vaccine (TIV) in protecting against influenza caused by antigenically-matching viral strains in a multinational phase III trial in children aged 6-59 months. LAIV was also significantly more effective than TIV in decreasing the incidence of culture-confirmed influenza illness in two open-label studies (in children with recurrent respiratory tract illnesses aged 6-71 months and in children and adolescents with asthma aged 6-17 years). LAIV did not differ significantly from placebo in preventing febrile illnesses in adults (primary endpoint) enrolled in a phase III trial. However, LAIV significantly reduced the incidence of febrile upper respiratory tract illnesses (URTI), severe febrile illnesses, febrile URTI-related work absenteeism and healthcare provider use. In another well designed trial in adults, LAIV significantly reduced the incidence of symptomatic, laboratory-confirmed influenza compared with placebo (but not intramuscular TIV). LAIV was generally well tolerated in most age groups, with the majority of adverse events being mild to moderate in severity, and runny nose/nasal congestion being the most common. In a large phase III trial, LAIV, compared with TIV, was associated with an increased incidence of medically significant wheezing in vaccine-naive children aged <24 months and an increased incidence of hospitalization in children aged 6-11 months; LAIV is not approved for use in children <24 months. LAIV was not always associated with high rates of seroconversion/seroresponse, particularly in older children and adults, or in subjects with detectable levels of haemagglutination-inhibiting antibodies at baseline. However, LAIV did elicit mucosal (nasal) IgA antibody responses and strong cell-mediated immunity responses. Only one confirmed case of LAIV virus transmission to a placebo recipient (who did not become ill) occurred in a transmission study conducted in young children. The immunogenic response to LAIV in young healthy children was not affected by concomitant administration with other commonly administered childhood vaccines. In conclusion, intranasal LAIV seasonal influenza vaccine is effective and well tolerated in children, adolescents and adults. LAIV was more effective than TIV in children, although this advantage was not seen in adults. In the US, LAIV is indicated for the active immunization of healthy subjects aged 2-49 years against influenza disease caused by virus subtypes A and type B contained in the vaccine.

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics – a systematic literature review

“…The protection in children (range 20–77%) and in healthy adults (range 50–59%) seen in the tropics and subtropics was comparable with that seen in developed countries 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74. Vaccine protection studies from the tropics and subtropics faced certain limitations.…”

Delivery strategies to enhance oral vaccination against enteric infections

“…The devastation resulting from the introduction of a diarrhoeal pathogen is exemplified by Haiti which experienced a cholera outbreak in the wake of the 2010 earthquake that was introduced to the country by United Nations (UN) relief soldiers from Tibet [8]. In such situations, oral vaccination is a quickly implementable strategy allowing for the containment and even prevention of such outbreaks [9][10][11]. Owing to this, oral vaccines have also generated interest as a frontline tool in biodefence against possible terrorist or biological weapon attack [12].…”

Yeast Surface Display of Capsid Protein VP7 of Grass Carp Reovirus: Fundamental Investigation for the Development of Vaccine Against Hemorrhagic Disease

“…Live vaccines have received increasing attention owing to their convenience and effectiveness [2,6,24]. In the case of developing a virus vaccine, a yeast-based vaccine is a good choice.…”