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Intervention Review

Vaccines for preventing influenza in healthy children

  1. Tom Jefferson1,*,
  2. Alessandro Rivetti2,
  3. Anthony Harnden3,
  4. Carlo Di Pietrantonj2,
  5. Vittorio Demicheli4

Editorial Group: Cochrane Acute Respiratory Infections Group

Published Online: 23 APR 2008

Assessed as up-to-date: 29 SEP 2007

DOI: 10.1002/14651858.CD004879.pub3


How to Cite

Jefferson T, Rivetti A, Harnden A, Di Pietrantonj C, Demicheli V. Vaccines for preventing influenza in healthy children. Cochrane Database of Systematic Reviews 2008, Issue 2. Art. No.: CD004879. DOI: 10.1002/14651858.CD004879.pub3.

Author Information

  1. 1

    The Cochrane Collaboration, Vaccines Field, Roma, Italy

  2. 2

    Azienda Sanitaria Locale ASL AL, Servizio Regionale di Riferimento per l'Epidemiologia, SSEpi-SeREMI - Cochrane Vaccines Field, Alessandria, Piemonte, Italy

  3. 3

    Institute of Health Sciences, Department of Primary Health Care, Oxford, Oxon, UK

  4. 4

    Regione Piemonte - Azienda Sanitaria Locale ASL AL, Health Councillorship - Servizio Regionale di Riferimento per l'Epidemiologia, SSEpi-SeREMI - Cochrane Vaccines Field, Torino, Piemonte, Italy

*Tom Jefferson, Vaccines Field, The Cochrane Collaboration, Via Adige 28a, Anguillara Sabazia, Roma, 00061, Italy. jefferson.tom@gmail.com. jefferson@assr.it; jefferson.tom@gmail.com.

Publication History

  1. Publication Status: New search for studies and content updated (conclusions changed)
  2. Published Online: 23 APR 2008

SEARCH

This is not the most recent version of the article. View current version (15 AUG 2012)

 

Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Background

The consequences of influenza in children and adults are mainly absenteeism from school and work. However, the risk of complications is greatest in children and people over 65 years old.

Objectives

To appraise all comparative studies evaluating the effects of influenza vaccines in healthy children; assess vaccine efficacy (prevention of confirmed influenza) and effectiveness (prevention of influenza-like illness) and document adverse events associated with influenza vaccines.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, issue 3); OLD MEDLINE (1950 to 1965); MEDLINE (1966 to September 2007); EMBASE (1974 to September 2007); Biological Abstracts (1969 to September 2007); and Science Citation Index (1974 to September 2007).

Selection criteria

Randomised controlled trials (RCTs), cohort and case-control studies of any influenza vaccine in healthy children under 16 years of age.

Data collection and analysis

Two review authors independently assessed trial quality and extracted data.

Main results

Fifty-one studies with 294,159 observations were included. Sixteen RCTs and 18 cohort studies were included in the analysis of vaccine efficacy and effectiveness. From RCTs, live vaccines showed an efficacy of 82% (95% confidence interval (CI) 71% to 89%) and an effectiveness of 33% (95% CI 28% to 38%) in children older than two compared with placebo or no intervention. Inactivated vaccines had a lower efficacy of 59% (95% CI 41% to 71%) than live vaccines but similar effectiveness: 36% (95% CI 24% to 46%). In children under two, the efficacy of inactivated vaccine was similar to placebo. Variability in study design and presentation of data was such that a meta-analysis of safety outcome data was not feasible. Extensive evidence of reporting bias of safety outcomes from trials of live attenuated vaccines impeded meaningful analysis.

Authors' conclusions

Influenza vaccines are efficacious in children older than two but little evidence is available for children under two. There was a marked difference between vaccine efficacy and effectiveness. No safety comparisons could be carried out, emphasizing the need for standardisation of methods and presentation of vaccine safety data in future studies. It was surprising to find only one study of inactivated vaccine in children under two years, given current recommendations to vaccinate healthy children from six months old in the USA and Canada. If immunisation in children is to be recommended as a public health policy, large-scale studies assessing important outcomes and directly comparing vaccine types are urgently required.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Vaccines for preventing influenza in healthy children

Children and the elderly are the two age groups that appear to have the most complications following an influenza infection. Influenza has a viral origin and often results in an acute respiratory illness affecting the lower or upper parts respiratory tract, or both. Viruses are mainly of two subtypes (A or B) and spread periodically during the autumn-winter months.
Many other viruses however, can also cause illness of the respiratory tract.

Diffusion and severity of the disease could be very different during different epidemics. Efforts to contain epidemic diffusion rely mainly on widespread vaccination. Recent policy from several internationally-recognised institutions, recommend immunisation of healthy children between 6 and 23 month of age (together with their contacts) as a public health measure.

The review authors found that in children aged from two years, nasal spray vaccines made from weakened influenza viruses were better at preventing illness caused by the influenza virus (82% of illnesses were prevented) than injected vaccines made from the killed virus (59%). Neither type was particularly good at preventing 'flu-like illness' caused by other types of viruses (33% and 36% respectively). In children under the age of two, the efficacy of inactivated vaccine was similar to placebo. It was not possible to analyse the safety of vaccines from the studies due to the lack of standardisation in the information given but very little information was found on the safety of inactivated vaccines, the most commonly used vaccine, in young children.

 

摘要

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

背景

疫苗預防健康兒童感染流行性感冒

兒童和成人感染流行性感冒常會導致曠課和缺勤。然而,出現併發症的風險最大的是兒童和超過65歲的成人。

目標

評讀所有的評估採用流感疫苗在健康兒童的比較性的研究;評估疫苗效力(預防證實的流感)和有效性(預防流感樣疾病)和記錄流感疫苗相關的副作用。

搜尋策略

我們搜尋了Cochrane Central Register of Controlled Trials (CENTRAL The Cochrane Library 2007, issue 3); OLD MEDLINE (1950年至1965年); MEDLINE (1966年至2007年9月); EMBASE (1974年至2007年9月); Biological Abstracts (1969年至2007年9月); 和 Science Citation Index (1974年至2007年9月)。

選擇標準

隨機對照試驗(Randomised controlled trials; RCTs),世代研究和病例對照研究任何流感疫苗在未滿16歲的健康兒童之情形。

資料收集與分析

2位回顧作者獨立地評估試驗品質和提取數據。

主要結論

51項研究與294,159項觀察被納入。16項隨機對照試驗和18項世代研究被包括在分析疫苗的效率和有效性。 從隨機對照試驗,活疫苗顯示在2歲以上的兒童,與安慰劑或不干預相比有82 %的效果 (95% confidence interval (CI) 71% to 89%)和33 % 的成效(95% CI 28% to 38%)。 不活化疫苗比活疫苗有一個較低的療效59 % (95% CI 41% to 71%),但有類似的效果: 36 % (95% CI 24% to 46%) 。 在2歲以下的兒童,滅活疫苗與安慰劑有相似的療效。由於研究設計以及數據的呈現方式各有不同,因此並不適合使用安全性的結果數據進行統合分析。許多證據指出減毒疫苗安全性結果的報告具有偏誤,因此無法進行有意義的分析。

作者結論

流感疫苗在2歲以上的兒童是有效的,但針對2歲以下兒童的療效證據有限。 疫苗效力和有效性之間有顯著差異。 沒有安全的比較可以進行,這點出了未來的研究需要標準化的方法和疫苗的安全性數據的呈現。 鑑於目前在美國和加拿大建議六個月以上健康的兒童接種疫苗,令人驚訝的發現只有一個2歲以下的兒童滅活疫苗的研究。 如果兒童接種疫苗是被建議作為一項公共衛生政策,那麼實在迫切需要採用大型研究評估重要的相關結果和直接比較疫苗類型。

翻譯人

本摘要由臺灣大學附設醫院林瑞原翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

疫苗預防健康兒童感染流感。 兒童和老年人似乎是兩個感染流感後有最多併發症的年齡組。 流感是由病毒所引起的,並且常常會引起急性呼吸道疾病,進一步影響下、上呼吸道(或是影響兩者)。病毒主要有兩種亞型(A或B),並且在秋冬季月份週期性散布。 但許多其他的病毒,也可能導致呼吸道的疾病。 疾病的擴散和嚴重程度在不同的流行病可以很不同。廣泛注射疫苗是遏制疫情擴散的主要方法。從幾個國際認可的機構最近的政策,建議6和23個月之間年齡的健康兒童接種疫苗(連同他們的接觸者)作為一個公共衛生的措施。 回顧作者發現針對2歲以上的兒童,採用減毒流感病毒所製造的鼻噴劑在預防流感病毒造成的不適方面,較注射非活性疫苗來得好(採用鼻噴劑者可預防82%不適;而注射非活性疫苗僅能預防59%)。 沒有一個疫苗類型在預防其他病毒所造成的類流感症狀是特別有效的(分別為33%和36%)。 在2歲以下的兒童,滅活疫苗與安慰劑的療效相似。 由於研究資料缺乏標準化,分析疫苗的安全性是不可能的, 但在年幼的兒童最常用的滅活疫苗的安全性資料很少被發現。