| Factor | LAIV | IIV (including egg-based and cell culture-based vaccines) | RIV |
| Route of administration | Intranasal spray | Either intramuscular injection or needle-free jet injector | Intramuscular injection |
| Type of vaccine | Live virus | Killed virus | Recombinant hemagglutinin proteins |
| Frequency of administration | Annually¶ | Annually¶ | Annually¶ |
| Approved age | Persons aged 2 to 49 yearsΔ | Persons aged ≥6 months◊ | Persons aged ≥18 years |
| Interval between 2 doses recommended for children aged ≥6 months to 8 years who require 2 doses¶ | ≥4 weeks | ≥4 weeks | Not approved for persons <18 years |
| Can be given to persons with risk factors for serious influenza-related complicationsΔ | No | Yes | Yes |
| Can be given to children with asthma or children aged 2 to 4 years with wheezing in the past year§ | No | Yes | Not applicable |
| Can be administered to family members or close contacts of immunosuppressed persons not requiring a protected environment | Yes if healthy | Yes | Yes |
| Can be administered to family members or close contacts of immunosuppressed persons requiring a protected environment (eg, hematopoietic cell transplant recipient) | No | Yes | Yes |
| Can be administered to family members or close contacts of persons with risk factors for influenza-related complications other than immunosuppression requiring a protected environment, as described in the previous row | Yes if healthy | Yes | Yes |
| Can be administered simultaneously with other vaccines | Yes¥ | Yes¥ | Yes¥ |
| If not administered simultaneously, can be administered within 4 weeks of a live vaccine | Prudent to space ≥4 weeks apart | Yes | Yes |
| If not administered simultaneously, can be administered within 4 weeks of an inactivated vaccine | Yes¥ | Yes¥ | Yes¥ |
Can be given to persons who have received:
| No | Yes | Yes |
* A decision is made annually regarding which virus strains will be targeted in the vaccine for the upcoming influenza season. Even in years in which the vaccine composition is the same as the previous season, annual vaccination is necessary since immunity wanes.
¶ Refer to UpToDate topic on seasonal influenza vaccination in children for details of the schedule for children 6 months through 8 years.
Δ Refer to the separate UpToDate table summarizing contraindications and precautions for the use of influenza vaccines.
◊ Approval varies by formulation.
§ Clinicians and vaccination programs should screen for possible reactive airways diseases when considering use of LAIV for children aged 2 through 4 years and should avoid use of this vaccine in children with asthma or a recent wheezing episode. Health care providers should consult the medical record, when available, to identify children aged 2 through 4 years with asthma or recurrent wheezing that might indicate asthma. In addition, to identify children who might be at greater risk for asthma and possibly at increased risk for wheezing after receiving LAIV, parents or caregivers of children aged 2 through 4 years should be asked: "In the past 12 months, has a health care provider ever told you that your child had wheezing or asthma?" Children whose parents or caregivers answer "yes" to this question and children who have asthma or who had a wheezing episode noted in the medical record within the preceding 12 months should not receive LAIV.
¥ Monitor for updates regarding coadministration with coronavirus disease 2019 (COVID-19) vaccines; experience to date is limited.