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AAFP Home Page > News & Publications > Journals > American Family Physician® > Vol. 74/No. 7 (October 1, 2006)

Cochrane for Clinicians

Putting Evidence into Practice

Vaccines for Preventing Influenza in Healthy Children

The Cochrane Abstract below is a summary of a review from the Cochrane Library. It is accompanied by an interpretation that will help clinicians put evidence into practice. Steven E. Roskos, M.D., presents a clinical scenario and question based on the Cochrane Abstract, followed by an evidence-based answer and a full critique of the review.

Clinical Scenario

A healthy one-year-old girl presents in the fall for well-child care and an immunization update. The girl's mother asks you whether her child should have an influenza vaccination.

Clinical Question

Would an influenza vaccination prevent illness in this patient, and would it be safe?

Evidence-Based Answer

Influenza vaccines have good efficacy (i.e., prevention of influenza) in children older than two years, and live, attenuated vaccine is more efficacious than trivalent, inactivated vaccine. Effectiveness (i.e., prevention of influenza-like illness, perhaps a clinically more important measure) is poor for all influenza vaccines in healthy children. Safety outcomes have not been analyzed. In children younger than two years, trivalent inactivated vaccine is no better than placebo and there are no good-quality safety data. There is some evidence that vaccines are effective in reducing school absence.1

Practice Pointers

Influenza in otherwise healthy children most commonly causes a febrile respiratory illness that leads to school (and, for their parents, work) absenteeism; however, it can result in hospitalization and, rarely, death. Hospitalization rates for influenza in children up to one year of age are comparable with those reported for 65-year-old adults. Influenza was responsible for an estimated 92 deaths per year in the 1990s among children younger than five years. One study revealed that 70 percent of deaths caused by influenza in children two to 17 years of age were in patients without an underlying medical condition.2

In 2002, the vaccination for influenza of all children six to 23 months of age was encouraged by the universal recommendations of the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention,3 which is endorsed by the American Academy of Family Physicians. The vaccine was included in the Vaccines for Children program in 2003.4 Recommendations for the 2005-2006 influenza season included administration of influenza vaccine to all children six to 23 months of age and any persons wishing to reduce the likelihood of becoming ill with influenza or of transmitting influenza to others.2 Support for extending vaccination to healthy younger children is provided largely by a two-year randomized study involving children six to 24 months of age.5 In this study, a high rate of seroconversion was found among children given the influenza vaccine, but there was only a small decrease in the rate of influenza during year 1 (culture-proven influenza was identified in 5.5 percent of children in the vaccination group versus 15.9 percent of those in the placebo group) and no difference in rates during year 2.5 Influenza vaccination did not reduce the likelihood of otitis media.5

Cochrane Abstract

Background: In children and adults, the consequences of influenza mainly are absences from school and work; however, the risk of complications is greatest in children and in persons older than 65 years.

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

Search Strategy: The reviewers1 searched the Cochrane Central Register of Controlled Trials (CENTRAL; Cochrane Library Issue 1, 2005), OLD MEDLINE (1966 to 1969), MEDLINE (1969 to December 2004), EMBASE (1974 to December 2004), Biological Abstracts (1969 to December 2004), and Science Citation Index (1974 to December 2004). They wrote to vaccine manufacturers and a number of corresponding authors of studies in the review.

Selection Criteria: Any randomized controlled trials (RCTs) and cohort or case-control studies of any influenza vaccine in healthy children younger than 16 years.

Data Collection and Analysis: Two authors independently assessed trial quality and extracted data.

Primary Results: Fifty-one studies involving a total of 263,987 children were included. Seventeen papers were translated from Russian. Fourteen RCTs and 11 cohort studies were included in the analysis of vaccine efficacy and effectiveness. From RCTs, live vaccines showed an efficacy of 79 percent (95% confidence interval [CI], 48 to 92) and an effectiveness of 33 percent (95% CI, 28 to 38) in children older than two years compared with placebo or no intervention. Inactivated vaccines had a lower efficacy (59 percent; 95% CI, 41 to 71) than live vaccines but similar effectiveness (36 percent; 95% CI, 24 to 46). In children younger than two years, the efficacy of inactivated vaccine was similar to placebo. Thirty-four reports containing safety outcomes were included: 22 of live vaccines, eight of inactivated vaccines, and four of both types. The most commonly presented short-term outcomes were temperature and local reactions. The variability in design of studies and presentation of data was such that meta-analysis of safety outcome data was not feasible.

Reviewers' Conclusions: Influenza vaccines are efficacious in children older than two years, but little evidence is available for children younger than two years. There was a marked difference between vaccine efficacy and effectiveness. That no safety comparisons could be carried out emphasizes the need for standardization of methods and presentation of vaccine safety data in future studies. It was surprising to find only one study of inactivated vaccine in children younger than two years given recent recommendations to vaccinate healthy children from six months of age in the United States and Canada. If immunization in children is to be recommended as public health policy, large-scale studies assessing important outcomes and directly comparing vaccine types are urgently required.

logoThese summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (

Two influenza vaccines are available for use in children. The trivalent, inactivated vaccine is given by intramuscular injection and is approved for children six months of age. It is given annually, except in previously unvaccinated children younger than nine years, for whom two doses are recommended, one month apart, with the second dose given before December. The live, attenuated vaccine is given by intranasal spray and is approved for healthy patients five to 49 years of age. It also is given annually, except in previously unvaccinated children five to nine years of age, who should receive two doses separated by six to 10 weeks.2

The Cochrane authors reviewed the literature and included randomized controlled trials (RCTs) and cohort and case-control studies.1 Efficacy and effectiveness results were taken mainly from 14 RCTs. Safety outcomes could not be combined for analysis because of the variability in study design and the diversity of safety outcomes reported, as well as the variable presentation of data. There are some lower-quality safety data available for trivalent, inactivated vaccine and live, attenuated vaccine in children, including those six to 23 months of age, from event-reporting networks and population-based studies.2 The most commonly reported adverse events from reporting networks and observational studies were fever, rash, injection-site reactions, irritability, insomnia, and seizures. Causality could not be proved, and in some studies the seizures were thought to be febrile seizures. One placebo- controlled study and one population-based study showed no increase in significant adverse events, but neither met criteria for inclusion in the Cochrane review.

Family physicians should present parents with the ACIP recommendations, explain that there is limited evidence that the vaccine is effective for children younger than two years, advise that the vaccine may reduce school absence in school-age children, and let parents decide. Future research is needed to clarify the benefit and safety of influenza vaccines in healthy children.


1. Smith S, Demicheli V, Di Pietrantonj C, Harnden AR, Jefferson T, Matheson NJ, et al. Vaccines for preventing influenza in healthy children. Cochrane Database Syst Rev 2006;(1):CD004879.

2. Harper SA, Fukuda K, Uyeki TM, Cox NJ, Bridges CB, for the Advisory Committee on Immunization Practices, Centers for Disease Control and Prevention (CDC).
Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP) [Published correction appears in MMWR Morb Mortal Wkly Rep 2005;54:750]. MMWR Recomm Rep 2005;54(RR-8):1-40.

3. Bridges CB, Fukuda K, Uyeki TM, Cox NJ, Singleton JA, for the Advisory Committee on Immunization Practices. Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 2002;51(RR-3):1-31.

4. Campos-Outcalt D. Influenza vaccine: new recommendations for infants and children aged 6 to 23 months. J Fam Pract 2004;53:874-7.

5. Hoberman A, Greenberg DP, Paradise JL, Rockette HE, Lave JR, Kearney DH, et al. Effectiveness of inactivated influenza vaccine in preventing acute otitis media in young children: a randomized controlled trial. JAMA 2003;290:1608-16.

The Author

STEVEN E. ROSKOS, M.D., is assistant professor in the Department of Family Medicine at the University of Tennessee Graduate School of Medicine, Knoxville.

Address correspondence to Steven E. Roskos, M.D., Dept. of Family Medicine, University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, U-67, Knoxville, TN 37920 (e-mail: Reprints are not available from the author.

EB CMEThis clinical content conforms to AAFP criteria for evidence-based continuing medical education (EB CME). EB CME is clinical content presented with practice recommendations supported by evidence that has been reviewed systematically by an AAFP-approved source. The practice recommendations in this activity are available at

Cochrane Briefs

Expectant Management vs. Surgical Treatment for Miscarriage

Clinical Question

What is the safety and effectiveness of expectant management versus surgical treatment for first-trimester miscarriage?

Evidence-Based Answer

Expectant management and surgical treatment are safe and effective for first-trimester miscarriage. Among patients who choose expectant management, there is a lower rate of pelvic infection but higher rates of mild bleeding, need for unplanned surgical treatment, and incomplete miscarriage.

Practice Pointers

When a nonviable first-trimester pregnancy is diagnosed, women have the option of waiting for the uterine contents to pass, choosing medical management with medications such as misoprostol (Cytotec), or undergoing dilation and curettage. Without intervention, more than 65 percent of missed abortions and 80 percent of incomplete and first-trimester abortions pass naturally within two to six weeks.1 Misoprostol 600 to 1,200 mcg vaginally on day 1, with a repeat dose if indicated on day 3, has been proven safe and effective. Success rates approach 95 percent, and women find their experience satisfactory.2,3 Surgical management includes vacuum extraction, suction curettage, or sharp curettage with or without dilation. Surgical management is the definitive treatment when other methods fail.

Nanda and colleagues reviewed the literature for trials comparing expectant management with surgical treatment for miscarriage. They found five trials with a total of 689 participants.

Expectant management had higher rates of incomplete miscarriage, need for unplanned surgical treatment, and bleeding, but a lower rate of pelvic infection (relative risk 0.29; 95% confidence interval, 0.09 to 0.87). Rates of infection ranged from 0 to 10 percent. Overall, there were two women in expectant management groups who required blood transfusion. However, rates of hemorrhage greater than 500 mL and bleeding requiring transfusion were not statistically significant between expectant management and surgical treatment groups. Two to 20 percent of women in the expectant management groups needed surgery. Unplanned surgical management usually was attributed to unacceptable pain, bleeding, or patient request. There were no differences in serious adverse events between the expectant management and surgical treatment groups.

Rates of complete abortion varied by study. In one study, the rate of complete abortion in the expectant management group was 81 percent at less than two weeks and 93 percent at seven weeks. Surgical treatment had a complete abortion rate of 97 percent at less than two weeks; no patients required second procedures. There is no clear indication for routine surgical management; therefore, patient preference should be respected.

Source: Nanda K, et al. Expectant care versus surgical treatment for miscarriage. Cochrane Database Syst Rev 2006;(2):CD003518.


1. Butler C, Kelsberg G, St Anna L, Crawford P. Clinical inquiries. How long is expectant management safe in first-trimester miscarriage? J Fam Pract 2005;54:889-90.

2. Nguyen TN, Blum J, Durocher J, Quan TT, Winikoff B. A randomized controlled study comparing 600 versus 1,200 microg oral misoprostol for medical management of incomplete abortion. Contraception 2005;72:438-42.

3. Creinin MD, Huang X, Westhoff C, Barnhart K, Gilles JM, Zhang J, for the National Institute of Child Health and Human Development Management of Early Pregnancy Failure Trial. Factors related to successful misoprostol treatment for early pregnancy failure. Obstet Gynecol 2006;107:901-7.

Exercises for Mechanical Neck Disorders

Clinical Question

How effective is exercise therapy for mechanical neck pain?

Evidence-Based Answer

There is some evidence that a variety of exercises help patients with mechanical neck pain. Evidence is strongest for a multimodal approach that includes exercise and mobilization or manipulation of the cervical spine, although this research has been criticized for having an imperfect control group.

Practice Pointers

Mechanical neck pain is caused by a variety of injuries and disease processes, including whiplash, myofascial neck pain, and degenerative cervical spine disease. Kay and colleagues reviewed the literature for randomized and quasi-randomized clinical trials on treatments for neck pain. Most studies (24) were of mechanical neck pain alone. The researchers also found one study of mechanical neck pain with some radicular signs, three studies of headache of cervical origin, and three involving a mixed group of patients with neck pain and neck disorder associated with headache or radicular symptoms. Studies were of fair quality. Although an earlier version of this systematic review was inconclusive, subsequent systematic reviews by other groups have found a benefit with exercise.

The authors found limited evidence of benefit for mechanical neck pain with a variety of types of exercise activity: active range-of-motion exercises without resistance, stretching and strengthening exercises, strengthening exercises alone, and eye-fixation exercises to improve proprioception. The strongest evidence, from four studies, was found for a multimodal approach that included exercise and mobilization or manipulation of the cervical spine (number needed to treat = 4 to 5).

The Philadelphia Panel, a panel of physicians and methodologic experts from the United States and Canada, developed an evidence-based guideline for the treatment of musculoskeletal disorders.1 According to this guideline, there is good evidence (grade A for pain and function, grade B for patient global assessment) to include supervised exercise programs alone, including proprioceptive and traditional exercises, for the management of chronic neck pain (i.e., lasting longer than 12 weeks).1 The Philadelphia Panel does not endorse manual therapy (i.e., cervical mobilization or manipulation) because the control group did not receive sham manual therapy.

Source: Kay TM, et al. Exercises for mechanical neck disorders. Cochrane Database Syst Rev 2005;(3):CD004250.


1. Philadelphia Panel evidence-based clinical practice guidelines on selected rehabilitation interventions for neck pain. Phys Ther 2001;81:1701-17.

The series coordinator for AFP is Clarissa Kripke, M.D., Department of Family and Community Medicine, University of California, San Francisco.