If you plan on bringing your kids into one of Pediatric Alliance’s sixteen office locations around the Pittsburgh metropolitan area for a flu vaccine, either during an office visit with a provider or at one of the convenient flu clinics we provide for our patients and families, they will be receiving a single brand of vaccine this year: a quadrivalent (4-strain) inactivated influenza vaccine (IIV) called Fluzone. According to the American Academy of Pediatrics, this vaccine is the preferred one for children from 6-months to 18 years of age. Most Pediatric Alliance offices will have a few doses of the intranasal quadrivalent live attenuated influenza vaccine (LAIV) called FluMist on hand for children who are extremely shot-averse. (Believe it or not, there really aren’t that many — more on that tomorrow on The PediaBlog.)

With several other brands of flu vaccines available on the market, it’s important to note that most pediatricians rely on the AAP and the CDC for guidance regarding the safest and most protective vaccines for children. In other words, evidence-based medical science is the overriding consideration in our vaccine purchasing decisions. (This is true for all vaccines.) This influenza season there are two new flu vaccines you may have heard of or read about. Both are quadrivalent inactivated flu vaccines and both use new technologies in their production. Until recently, vaccine manufacturers all used chicken eggs in their production processes and that creates a couple of problems. First:

Most vaccine manufacturers make their annual vaccine using chicken eggs and a manufacturing system that was established in the 1940s.

The egg-based production system is used to make almost 500 million doses of flu vaccine every year. Each dose of the vaccine requires the use of 1 or 2 chicken eggs, so as you can see, many millions of chicken eggs are needed every year to produce enough vaccine for the entire world.


That’s a lot of eggs — and a lot of hens to lay those eggs!

The other problem with the existing technology is that replicating four different strains of influenza using chicken eggs takes time. Production of egg-based flu vaccines begins in February, at a time when influenza is most active — and prone to mutations — in the Southern Hemisphere. Vaccine production using newer technologies means a later start date for manufacturing to begin (April), allowing longer surveillance of flu activity “down under” and more time to make adjustments to any of the components of the intended flu vaccine based on observed mutations or in the event of the emergence of new strains.

One new influenza vaccine is called Flublok and it contains no egg protein at all. Instead, pieces of viral DNA are used in its production. The U.S. Food and Drug Administration has approved Flublok for use in adults beginning at 18 years old. The second new vaccine is called Flucelvax and it is approved down to the age of 4 years old. Therefore, children under 4 must still receive the traditional flu vaccines. Flucelvax is made using canine (dog) kidney cells. And Flucelvax is not completely egg-free; the influenza A (H1N1) component of this vaccine is grown using chicken eggs.

So the biggest advantages to these two new influenza vaccines is that their production times will be reduced (by about half) and the ability to wait to begin production may improve their accuracy and, thus, their efficacy in preventing circulating strains. Jill Daly discovered that these two vaccines are indeed more efficacious, especially among older people:

“It appears that the egg-free products were about 10 percent better,” said UPMC’s Richard Zimmerman, chief of the Pittsburgh site of the multicenter U.S. Influenza Vaccine Effectiveness Network of the Centers for Disease Control and Prevention.


Children who have egg allergies will not benefit from the emergence of these new vaccines for three reasons. First, the completely egg-free Flublok is not approved for children under 18 years old. Second, Flucelvax has egg protein in it. And third, IT DOESN’T MATTER; the chicken egg-produced influenza vaccines that have been in use for decades are safe for people with egg allergies, as we were reminded last week in the AAP’s seasonal flu vaccine recommendations:

All children with egg allergy of any severity can receive an influenza vaccine without any additional precautions beyond those recommended for all vaccines.


Regardless of the severity of reaction to egg protein, all children who are allergic to eggs can safely receive annual influenza vaccines with no special precautions. These two new influenza vaccines (egg-free Flublok and “egg-lite” Flucelvax) were created not to benefit the egg-allergic, but to lower the cost of production and improve the efficacy of flu vaccine. The old chicken egg versions of flu vaccine that we have been giving for decades are safe and effective for everyone, including those with egg allergies. If parents have concerns about the safety of any of the immunizations we offer to protect their children from vaccine-preventable diseases, they know they can talk it over with their chosen and trusted board-certified pediatricians at Pediatric Alliance.


(Google Images)