Influenza Vaccine Health Advisory

Date: September 15, 2011

To: Health Care Providers
From: Mark Netherda, Interim Public Health Officer
Public Health Disease Control Unit
Phone: (707) 565-4573
Fax: (707) 565-4565

Who Should Get Vaccinated Against Influenza?

On February 24, 2010, the Advisory Committee on Immunization Practices (ACIP) recommended that everyone 6 months and older should get a flu vaccine each year starting with the 2010-2011 influenza season. The recommendation is intended to remove barriers to flu immunization, such as the need to determine whether each person has a specific indication for vaccination, and protect as many people as possible against the dangers of influenza.

While everyone should get a flu vaccine each flu season, it's especially important that certain people get vaccinated either because they are at high risk of having serious flu-related complications or because they live with or care for people at high risk for developing flu-related complications.

This includes:

• Children aged 6 months--4 years (59 months);
• People 50 years and older;
• People with chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus);
• People who are immunosuppressed (including immunosuppression caused by medications or by human immunodeficiency virus);
• Women who are or will be pregnant during the influenza season;
• Children aged 6 months to 18 years receiving long-term aspirin therapy and who therefore might be at risk for experiencing Reye's syndrome after influenza virus infection;
• Residents of nursing homes and other chronic-care facilities;
• American Indians/Alaska Natives;
• People who are morbidly obese (body BMI >40);
• Health-care personnel;
• Household contacts and caregivers of children younger than 5 years and adults 50 years and older, with particular emphasis on vaccinating contacts of children younger than 6 months; and
• Household contacts and caregivers of persons with medical conditions that put them at higher risk for severe complications from influenza.

When to Vaccinate?

Now is the optimal time to vaccinate. Public Health recommends vaccinating whenever the patient and vaccine are in the same place at the same time. Continue vaccinating through the end of March, which is considered the end of the flu season.

Vaccination for Children - NEW Information

Influenza vaccination is recommended for all children aged 6 months up to their 19th birthday.

All children 6 months through 8 years of age are recommended to receive 2 doses of 2011-12 flu vaccine 4 or more weeks apart unless they have received at least 1 dose of flu vaccine last flu season. Children who received at least one dose of the 2010-2011 seasonal influenza vaccine will need only one dose in 2011-2012. (Note that for the 2011-2012 season, the ACIP recommends that the TIV "Afluria" not be given to children younger than 9 years old, although it is approved for children aged 5 years and older.)

The first dose should be given as soon as vaccine becomes available, and the second dose should be given 28 or more days after the first dose.

Vaccination for Adults

Everyone 6 months of age and older are recommended to receive the flu vaccine, which includes even the healthiest adults. Vaccination is especially important for people at higher risk of serious influenza complications or people who live with or care for people at higher risk for serious complications.

Persons working in health care settings also should be vaccinated annually against influenza. Vaccination of health care professionals has been associated with reduced work absenteeism and with fewer deaths among nursing home patients.

People who should NOT be vaccinated include:

• People who have a severe allergy to chicken eggs (See below for information about less severe egg allergies.),
• People who have had a severe reaction to an influenza vaccination,
• People who have developed Guillian-Barré syndrome within 6 weeks of getting an influenza vaccine,
• Children younger than 6 months of age (influenza vaccine is not approved for children in this age group), and
• People who have a moderate to severe illness with a fever (they should wait until they recover to get vaccinated).

Vaccination of People with Egg Allergy - NEW Information

For the 2011-2012 season, there is a more permissive influenza vaccination recommendation for persons with egg allergies. Based on a thorough review of several recent studies, administration of both full doses and split doses of TIV have been tolerated by people with egg allergies, without serious reactions. The Advisory Committee on Immunization Practices (ACIP) now recommends that for the 2011-2012 influenza season, people who have experienced only hives from consuming eggs can receive TIV intramuscularly as long as they are treated by a health care provider who is familiar with the potential manifestations of egg allergies and can be observed by a health care professional for at least 30 minutes after receiving each dose. The 2011 ACIP recommendations has an algorithm to help guide clinician decision-making regarding vaccination of people with egg allergy. LAIV should not be used in these patients.

Influenza Vaccine Options - New Information

A new intradermal trivalent inactivated vaccine that is given into the dermal layer of the skin via a single-dose, prefilled microinjection syringe and that contains less antigen than the intramuscular TIV formulations is now available (IM vaccine contains 15 mcg of hemagglutinin per strain of influenza in a 0.5 mL dose. Intradermal vaccine contains 9 mcg of hemagglutinin per strain of influenza in a 0.1 mL dose). The intradermal vaccine was approved for use in people 18 through 64 years of age in 2011. Other vaccines include the regular and high dose trivalent inactivated vaccine (TIV). The "high dose" vaccine, containing 4 times the amount of antigen as the regular TIV, is approved for use in people 65 and older. The CDC recommends neither for nor against its use. The live, attenuated intranasal influenza vaccine (LAIV), given as a nasal spray, is approved for healthy people 2-49 years of age who are not pregnant.