Background
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Inactivated influenza vaccines (IIV): These include subunit vaccines (containing only surface antigens); split-virion vaccines (in which virus is inactivated with disrupting agents, yielding surface and internal antigens); and whole virion inactivated vaccines (containing whole inactivated viruses). Among these, only split-virion vaccines are currently licensed in the United States. Most are administered intramuscularly; one intradermal preparation is available. IIV is available from a number of different manufacturers; age indications for the different preparations differ. IIV preparations are available for children as young as six months of age.
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Live-attenuated (cold-adapted) influenza vaccines (LAIV): These intranasally-administered vaccines contain virus which can multiply only in the nasal passages. LAIV is licensed for persons 2 through 49 years old and is recommended for healthy, non-pregnant individuals who do not have chronic medical conditions, due to relative lack of data in the other populations [8].
Study objectives
Methods/design
Eligibility criteria
Study selection
Data collection and extraction
Outcomes of interest
Quality assessment
Statistical analysis
Subgroup analysis
Publication bias
Author contact
Reporting
Evaluating the quality of evidence
Quality assessment | Number of patients | Effect | Quality | Importance | ||||||||
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Number of studies | Design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | LAIV | IIV | RR (95% CI) | Absolute | ||
Laboratory confirmed influenza (follow-up; assessed with: PCR or viral culture)
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Randomized trials | ⊕ ⊕ ⊕ ⊕ HIGH | CRITICAL | ||||||||||
Influenza like illness (follow-up; assessed with)
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Randomized trials | ⊕ ⊕ ⊕ ⊕ HIGH | IMPORTANT | ||||||||||
Hospitalization (follow-up; assessed with)
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Randomized trials | ⊕ ⊕ ⊕ ⊕ HIGH | CRITICAL | ||||||||||
Medically attended respiratory illness (follow-up; assessed with)
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Randomized trials | ⊕ ⊕ ⊕ ⊕ HIGH | CRITICAL | ||||||||||
Fever due to vaccination (follow-up mean, assessed with)
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Randomized trials | ⊕ ⊕ ⊕ ⊕ HIGH | IMPORTANT | ||||||||||
Guillain-Barre syndrome (follow-up mean, assessed with)
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Observational study | ⊕ ⊕ ΟΟ LOW | IMPORTANT | ||||||||||
Anaphylaxis (follow-up mean, assessed with)
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Observational study | ⊕ ⊕ ΟΟ LOW | CRITICAL |