New vaccine safe for egg allergic

More choices than ever for flu shots

Egg allergy should no longer prevent someone from receiving the seasonal influenza vaccine. A recombinant flu vaccine (Flublok by Protein Sciences Corp.) that is not produced with eggs will be available this fall for people between the ages of 18 and 49.

The Centers for Disease Control and Prevention has advised health care providers that they can vaccinate people who have only a hives reaction to eggs with the traditional influenza vaccine if they are medically observed for a half-hour after administration. People who have had an anaphylactic reaction or who have never been exposed to eggs but are suspected of having an egg allergy due to allergy testing should consult with a physician before being vaccinated, the CDC said.

However, vaccination with Flublok, also known as RIV3, is now an alternative for people with any type of egg allergy. Produced using insect cells and recombinant DNA technology, it is provided in single-dose vials and has a shelf life of only 16 weeks after manufacture. CDC advises health care providers to check the expiration date before using the product.

Flublok is just one of an unprecedented variety of influenza vaccines that will be available this season. In June, the Advisory Committee on Immunization Practices (ACIP), an expert panel that advises CDC, approved the use of quadrivalent vaccines, which protect against two influenza A strains and two influenza B strains. (The trivalent vaccines target only one B strain.)

Fluzone by Sanofi Pasteur is available as an intradermal vaccine, with a tiny needle, and in a high-dose version, with four times the usual amount of antigen, geared toward people 65 years and older. The high-dose version produces a better immune response in older adults, but it's not clear yet whether that equates to greater protection, CDC says.

Flucelvax by Novartis is produced in a mammalian cell culture, but because the seed used to initiate production was egg-based, it is not considered to be completely egg-free. A Novartis representative told ACIP that no egg protein can be detected in the vaccine.

The quadrivalent vaccine also is available as a nasal spray – FluMist by MedImmune, which is a live attenuated vaccine that is approved for people ages 2 to 49.

Despite the range of products, vaccine effectiveness remains a concern. The 2012-2013 flu season began earlier than usual and peaked in late December. CDC reported 152 influenza-related pediatric deaths, more than any year since 1997, except for the 2009 H1N1 pandemic.

But the main tool for preventing influenza transmission was only 52% effective, reported Mark Thompson, PhD, an epidemiologist in the influenza division. It was especially problematic against influenza A (H3N2), with an effectiveness of 19% for people 65 and older and 40% for people 18 to 49.

There were some bright spots for the vaccine. It reduced the risk of outpatient medical visits due to influenza A (H3N2) by 44% for everyone but children ages 9 to 17 and people 65 and older, and it reduced medical visits due to influenza B by 62% for people of all ages. CDC also reported that it reduced the risk of hospitalization.

"The vaccine may have reduced the likelihood of more severe illness," Thompson said.