Efficacy and Safety of a Live Attenuated, Cold-Adapted Influenza Vaccine, Trivalent Against Culture-Confirmed Influenza in Young Children in Asia

Tam, John S.; Capeding, María Rosario; Lum, Lucy Chai See; Chotpitayasunondh, Tawee; Jiang, Zai-fang; Huang, Li‐Min; Lee, Bee Wah; Qian, Yuan; Samakoses, Rudiwilai; Lolekha, Somsak; Rajamohanan, K Pillai; Narayanan, Sathya; Kirubakaran, Chellam; Rappaport, Ruth; Razmpour, Ahmad; Gruber, William C.; Forrest, Bruce D.

doi:10.1097/inf.0b013e31806166f8

Cited by 165 publications

(121 citation statements)

References 26 publications

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“…Seasonal influenza vaccination provided 20–77% in children depending on antigenic match, against laboratory‐confirmed influenza (Table 2). 18, 47, 48, 49, 50, 51, 52, 53, 54, 55 Vaccinating school children provided 23·3% (66·3–74·9) protection against influenza and indirect protection of 61% (5·8–84·7) for household contacts 56. Vaccinating pregnant women prevented laboratory‐confirmed influenza in both mothers (50%) and their infants up to 6 months of age (49–63%) 57, 58.…”

Section: Resultsmentioning

confidence: 99%

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

Hirve

Lambach

Paget

et al. 2016

Influenza Resp Viruses

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AimThe evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries.MethodGlobal health databases were searched in three thematic areas – policy, availability and protective benefits in the context of human seasonal influenza vaccine in the tropics and subtropics. We excluded studies on monovalent pandemic influenza vaccine, vaccine safety, immunogenicity and uptake, and disease burden.ResultsSeventy‐four countries in the tropics and subtropics representing 60% of the world's population did not have a national vaccination policy against seasonal influenza. Thirty‐eight countries used the Northern Hemisphere and 21 countries the Southern Hemisphere formulation. Forty‐six countries targeted children and 57 targeted the elderly; though, the age cut‐offs varied. Influenza vaccine supply increased twofold in recent years. However, coverage remained lower than five per 1000 population. Vaccine protection against laboratory‐confirmed influenza in the tropics ranged from 0% to 42% in the elderly, 20–77% in children and 50–59% in healthy adults. Vaccinating pregnant women against seasonal influenza prevented laboratory‐confirmed influenza in both mothers (50%) and their infants <6 months (49–63%).ConclusionGuidelines on vaccine composition, priority risk groups and vaccine availability varied widely. The evidence on vaccine protection was scarce. Countries in the tropics and subtropics need to strengthen and expand their evidence‐base required for making informed decisions on influenza vaccine introduction and expansion, and how much benefit to expect.

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Section: Resultsmentioning

confidence: 99%

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

Hirve

Lambach

Paget

et al. 2016

Influenza Resp Viruses

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“…Yet this is where most studies estimating the value of vaccination take place [21,22]. By contrast, source populations that contribute more to influenza's evolution (e.g., China and India) have almost zero vaccination [32][33][34], and few studies of vaccination occur there [35].…”

Section: Introductionmentioning

confidence: 98%

The beneficial effects of vaccination on the evolution of seasonal influenza

Wen

Malani

Cobey

2017

Preprint

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Although vaccines against seasonal influenza are designed to protect against currently circulating strains, they may also affect the emergence of antigenically divergent strains and thereby change the rate of antigenic evolution. Such evolutionary effects could change the benefits that vaccines confer to vaccinated individuals and the host population (i.e. private and social benefits). To investigate vaccinations potential evolutionary impacts, we simulated the dynamics of an influenza-like pathogen in an annually vaccinated host population. On average, vaccination decreased the cumulative amount of antigenic evolution of the viral population and the incidence of disease. Vaccination at a 5% random annual vaccination rate (48% cumulative vaccine coverage after 20 years) decreased cumulative evolution by 56% and incidence by 76%. To understand how the evolutionary effects of vaccination might affect its private and social benefits over multiple seasons, we fit linear panel models to simulated infection and vaccination histories. Including the evolutionary effects of vaccination lowered the private benefits by 14% but increased the social benefits by 30% (at a 5% annual vaccination rate) compared to when evolutionary effects were ignored. Thus, in the long term, vaccines' private benefits may be lower and social benefits may be greater than predicted by current measurements of vaccine impact, which do not capture long-term evolutionary effects. These results suggest that conventional vaccines against seasonal influenza could greatly reduce the burden of disease by slowing antigenic evolution like universal vaccines. Furthermore, vaccination's evolutionary effects compound a collective action problem, highlighting the importance on social policies concerning vaccination.

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“…Multiple prospective, randomized, controlled studies have described the efficacy of live attenuated influenza vaccine (LAIV) in children and adolescents compared with placebo and with trivalent inactivated influenza vaccine (TIV) 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 . LAIV provided levels of efficacy against influenza illness that, in the three comparative studies conducted, were significantly higher than those provided by TIV 1 , 3 , 7 .…”

Section: Introductionmentioning

confidence: 99%

Efficacy of live attenuated influenza vaccine in children 6 months to 17 years of age

Belshe

Toback²,

Yi³

et al. 2010

Influenza Resp Viruses

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Please cite this paper as: Belshe et al. (2010). Efficacy of live attenuated influenza vaccine in children 6 months to 17 years of age. Influenza and Other Respiratory Viruses 4(3), 141–145. Background It has been suggested that live attenuated influenza vaccine (LAIV) may be less effective in older individuals because of prior wild‐type influenza infections. LAIV is currently approved in the United States, South Korea and Hong Kong for individuals 2–49 years of age. Objective To examine data from previously published pediatric studies to determine the efficacy of LAIV in various age groups. Methods Four studies in which the subject age range exceeded 36 months were identified: one 2‐year study comparing LAIV with placebo and three 1‐year studies comparing LAIV with trivalent inactivated influenza vaccine (TIV). Efficacy against any strain regardless of antigenic similarity to vaccine was analyzed by age; age groups were based on the study design and sample size. A logistic regression model was used to assess whether age, as a continuous variable, was an effect modifier on LAIV efficacy. Results The efficacy of LAIV did not vary with age in children aged 15–84 months compared with placebo or in children aged 6 months to 17 years compared with TIV. Conclusions The available data from prospective, randomized studies in children does not support the concept that prior repeated exposure to influenza, either through wild‐type infection or vaccination with live, attenuated or inactivated vaccines, reduces the efficacy of LAIV compared with placebo or TIV. The decreased immunologic responses to LAIV reported in older individuals or those with pre‐existing immunity do not appear to translate into reduced protection from influenza in children.

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Efficacy and Safety of a Live Attenuated, Cold-Adapted Influenza Vaccine, Trivalent Against Culture-Confirmed Influenza in Young Children in Asia

Abstract: CAIV-T was well tolerated and effective in preventing culture-confirmed influenza illness over multiple and complex influenza seasons in young children in Asia.

Cited by 165 publications

References 26 publications

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

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

The beneficial effects of vaccination on the evolution of seasonal influenza

Efficacy of live attenuated influenza vaccine in children 6 months to 17 years of age

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