Those looking for flu vaccines made without the live virus and free of preservatives, eggs or thimerosal may have found their alternative.
The United States Food and Drug Administration (FDA) approved a vaccine this week named Flublok from Protein Sciences for use in adults ages 18 to 49. The vaccine is available in limited use for this season, but is scheduled to be made widely available for the 2013-2014 season.
Since the development of flu vaccines for projected strains starts in February, this approval is right on track for next year. The manufacturer has not updated availability for this year yet, but some availability is projected.
This vaccine, however, will not take as long to make, perhaps making it a huge breakthrough for widespread vaccination. Flu vaccine manufacturing starts in February for the following winter because they typically use fertilized eggs to grow influenza virus cultures, then have to purify and combine incubated viruses, which can take up to six months. That's why new strains are not included.
This vaccine is different, and may be a real alternative for those with egg allergy since it is the first 100 percent egg-free vaccine.
Using cell-based technology from insects that are naturally infected with a baculovirus, the company cultures the cells and genetically modifies the virus to create proteins needed to create immunity. Since no virus is grown, egg components are not needed and the vaccine can be manufactured within two months time.
According to the FDA's website, however, this vaccine will not replace current vaccinations:
"This is an important advance that will supplement current egg-free vaccines. The more manufacturing alternatives there are available, the better we can respond to public health emergencies in a timely manner." -- Jerry P. Weir, Ph.D., director of the division of viral products in FDA's Center for Biologics Evaluation and Research
Still, in its approval, the FDA admits the speed of production is a clear advantage. In fact, in 2006 there was a major push for cell-based flu vaccines to prepare for potential world-wide epidemic. There has also been a long history of questions brought against vaccine manufacturers about contagious release associated with vaccine manufacturing. Because of Flublok's new technology it is also said to eliminate infectious risk associated with traditional vaccine manufacturing.
For vaccine opponents, perhaps some medical officials are hoping that these opponents will be won over by the fact that this vaccine contains no live virus, thimerosal, antibiotics, latex, formaldehyde, other preservatives or pharmaceutical agents. Since there are no antibiotic agents, it is also not thought to contribute to continuing concern about antibiotic resistance.
Like other flu vaccines, this vaccine is not designed to protect other respiratory infections. Vaccines in general work by triggering the immune system to produce antibodies that help fight off the infection. The protein derived in Flublok is the same protein used in all inactivated flu virus vaccines to trigger antibody reaction. According to the manufacturer, the egg-based technology dates back to the 1950s. Currently guarding for the same three strains as the 2012-2013 vaccines, Flublok is received in the arm just like other inactive flu virus vaccines.
Another vaccine, Flucelvax, was approved in November 2012 for those ages 18 and over using cell-based technology. Its manufacturer, Novartis, does not provide as much information about its technology and studies. This vaccine also contains latex, which Flublok does not. Although Flucelvax is not cultured with eggs, it is not advertised as egg-free, which may mean it uses eggs as some point during the production. Their website does not specify.
Reactions to this vaccine in a study of 4,648 people followed for six months showed 37 percent of vaccine recipients had pain at the injection site compared to 8 percent of those receiving a placebo shot. Other local reactions, such as redness, swelling and bruising were similar to placebo reactions. Systemic adverse reactions of headache, fatigue, muscle pain, fever, joint pain, nausea and chills were also similar to that of the placebo. One person was hospitalized and recovered from a swelling of the heart's membrane sac. This person did receive the Flublok, but a causal relationship was not identified. This information is all in the Flublok package insert.
There have been no well-controlled studies for pregnant women, only in rats. It is also not known if the vacccine is excreted in human milk for nursing mothers. So far it has not been approved for children under 18 years of age, because effectiveness has not been proven. While the safety and effectiveness of Flublok has not been established in persons over 50 years of age, approval for those over 49 is expected later this year. Protein Sciences is a vaccine manufacturer based in Meriden, CT, with offices expanded to Pearl River, NY, in late 2012.
As with other vaccines, it is stated that this vaccine does not protect everyone. Manufacturers also address concerns about the neurological disease Guillain-Barre Syndrome (GBS):
"The 1976 swine influenza vaccine was associated with an increased frequency of GBS. Evidence for a causal relation of GBS with other influenza vaccines is inconclusive; if an excess risk exists, it is probably slightly more than one additional case per 1 million persons vaccinated. If Guillain-Barré Syndrome (GBS) has occurred within 6 weeks of receipt of a prior influenza vaccine, the decision to give Flublok should be based on careful consideration of the potential benefits and risks." -- Flublok package insert
Protein Sciences is also working on a cell-based vaccine for type I diabetes and gene therapy for lipoprotein lipase deficiency.