SEASONAL INFLUENZA immunization in the US continues to be a problem due to factors such as inadequate early vaccination coverage, improper handling of the vaccine, and lack of accurate information provided to the public. Only 59% of eligible children and 43.3% of eligible adults received the influenza vaccine during the 2016-2017 season.1 Even so, the CDC estimates that vaccination has prevented an estimated 5.29 million illnesses, 2.64 million medical visits, and 84,700 influenza-associated hospitalizations.2,3
According to the CDC, influenza has resulted in 9.2 million to 35.6 million illnesses, 140,000 to 710,000 hospitalizations, and 12,000 to 56,000 deaths annually since 2010.4 That is astounding in terms of healthcare cost as well as work and school absenteeism.
The 2017-2018 flu season was one of the most aggressive on record in the number of reported cases, hospitalizations, and deaths.2,3 According to CDC surveillance data published in June 2018, what contributed most to last flu season's record flu numbers was not a lack of vaccine effectiveness, but rather the low rate of early vaccination coverage.5,6 Vaccination early in the flu season is key to reducing the overall incidence of flu because it reduces disease transmission and antigenic drift, which occurs when the circulating virus undergoes mutations that over time differentiate it from the strain covered in the vaccine.7
This season, we have the opportunity to vaccinate people who have been previously unable to receive an influenza vaccine or who have opted out due to limited vaccine options. One reason is the return of the quadrivalent live attenuated influenza vaccine (LAIV4), the intranasal formulation also known as FluMist. It had been removed from the market during the past two seasons due to concerns about its effectiveness. The Advisory Committee on Immunization Practices (ACIP) and CDC voted to resume its use for the 2018-2019 season because changes in the formulation are expected to improve its coverage.8
Under current guidelines, people with a history of egg allergy who have experienced only urticaria (hives) after exposure to egg should receive influenza vaccine. Any licensed, recommended, and age-appropriate influenza vaccine (that is, any IIV, RIV4, or LAIV4) that is otherwise appropriate for the patient's age and health status may be used.
People who have had symptoms other than hives after exposure to eggs (such as angioedema, respiratory distress, lightheadedness, or recurrent emesis) or who have needed epinephrine or another emergency medical intervention to manage symptoms can also receive any licensed flu vaccine that is otherwise appropriate for their age and health, but vaccination should occur in a medical setting by a practitioner qualified to recognize and manage severe allergic reactions.8,9 However, “a previous severe allergic reaction to influenza vaccine, regardless of the component suspected of being responsible for the reaction, is a contraindication to future receipt of the vaccine.”9
For patients with an aversion to I.M. injections, several vaccine formulations can be administered via a jet injector, which uses a high-pressure, narrow stream of fluid to penetrate the skin instead of a hypodermic needle. Jet injectors may be powered by compressed gas or springs. These varied options give healthcare providers even more potential to increase vaccination rates in previously undervaccinated groups early in the season.8,9
Influenza immunization is recommended for everyone age 6 months or older who does not have any contraindications. Although vaccination by the end of October is optimal, the CDC encourages people to get vaccinated throughout the flu season, even into January and beyond.10
When choosing the best vaccine for any eligible patient, clinicians must take into account many factors: age indication, dose, the quantity of strains included (trivalent or quadrivalent), vaccine components (live attenuated or inactivated virus), the manufacturing process (virus grown in eggs, cell-based, or recombinant), and administration method/route (intranasal spray, I.M. injection, or jet injector). No intradermal formulation is available for this flu season. For details on vaccines available for the current flu season, visit www.cdc.gov/flu/professionals/acip/2018-2019/2018-19summary.htm#iivs.
The CDC and ACIP express no preferences for any of the vaccine formulations. The American Academy of Pediatrics recommends injectable vaccine as the first choice for children; however, it also endorses use of the nasal spray “for children who would not otherwise receive the flu shot, as long as they are 2 years of age or older and healthy without an underlying medical condition.” The goal is to optimize protection for children of all ages.11
Here are highlights of practice recommendations clinicians should follow to optimize vaccine coverage for the 2018-2019 flu season. As always for any medication, refer to the package insert for complete dosing and administration information.
FluMist is back. This LAIV4 vaccine is administered via nasal spray and approved for persons ages 2 to 49 years, unless contraindicated. The LAIV4 is the only formulation administered by the intranasal route (see Intranasal administration tips). Contraindications include concurrent aspirin therapy in children and adolescents due to the risk of Reye syndrome, and a history of severe allergic reactions to any component of the vaccine, including egg protein, or to a previous dose of any influenza vaccine. Warnings and precautions address possible risks or lack of safety data regarding its use in pregnant or nursing women, immunosuppressed patients, patients with asthma, geriatric patients, and children under age 2 years. Antiviral medications effective against influenza A and/or B may reduce the vaccine's effectiveness if given within 48 hours before or 2 weeks after the vaccine.12 Consult the product insert for complete information and carefully assess patients' medical histories and current health status before administering the vaccine.
Follow vaccine storage and handling directions. Many vaccines are packaged in single-dose vials or manufacturer-filled syringes that do not contain a preservative (bacteriostatic) agent to protect against contamination. Any single-dose vial should be discarded after use for a single patient or if the protective cap has been removed for any reason. The same applies for an activated manufacturer-filled syringe. Once the needle cap is removed or a needle has been attached to the syringe, the sterile seal is no longer intact and the integrity of the vaccine is compromised.
Multiple-dose vials do contain a bacteriostatic agent, so they may be opened and used until the expiration date unless it becomes contaminated. The CDC and other safety experts recommend using prefilled syringes or single-dose vials whenever possible and restricting the use of multiple-dose vials to single patients if feasible.13,14
Do not prepare individual doses in advance. Clinicians should prepare each vaccine dose immediately before administration. Besides increasing the risk of medication errors, preparing doses in advance is associated with vaccine waste and raises the risk that inappropriate environmental temperatures will reduce vaccine effectiveness or that vaccines without a preservative will become contaminated.15
Administer I.M. injections at the right site. The dose of vaccine must be delivered to the recommended anatomical location depending on the patient's age and weight. For adults and older children, the recommended site for I.M. influenza vaccination is the deltoid muscle. The preferred site for infants and young children is the anterolateral aspect of the thigh.16 Appropriate needle length depends on age and body mass. Aspiration before injection and rubbing or massaging the site after injection are not recommended.15,16
Nurses on the front line
First-line providers are critically important in advocating for safe and effective immunization practices for patients. We now have more information and resources at our disposal than ever before to work toward the goal of vaccinating every eligible patient.
Intranasal administration tips12,16
A dose of the LAIV4, the intranasal formulation also known as FluMist, is delivered via a nasal sprayer containing a single total dose of 0.2 mL with a dose-divider clip that allows introduction of one 0.1-mL spray into each nare. To administer a dose, first check the expiration date and place the patient in an upright position. Remove the rubber tip protector but do not remove the dose-divider clip at the other end of the sprayer.
Insert the tip of the applicator slightly into one nare. Depress the plunger as rapidly as possible. Then pinch and remove the dose-divider clip from the plunger and repeat the procedure in the other nare.
Occluding the opposite nare and sniffing (active inhalation) during administration is not necessary. If the patient coughs or sneezes, the vaccine dose need not be repeated.
3. Garten R, Blanton L, Elal AIA, et al Update: influenza activity in the United States during the 2017-18 season and composition of the 2018-19 influenza vaccine. MMWR Morb Mortal Wkly Rep
9. Grohskopf LA, Sokolow LZ, Broder KR, Walter EB, Fry AM, Jernigan DB. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices—United States, 2018-19 influenza season. MMWR Recomm Rep