Flu Vaccines May Not Work Because They Grow In Chicken Eggs


Despite getting their annual shots, many still suffered from coughs and colds last year. Flu vaccines lost their effectiveness due to faulty manufacturing process, a new research reveals.

Manufacturing Flu Vaccines

It was fortunate that experts correctly predicted the specific viral strain that would dominate the season. What was dismal is the 34 percent effectiveness of the flu vaccine — resulting to a great number of individuals contracting flu despite having their shots.

Scientists from the University of Rochester and University of Chicago claim that the growth of flu virus within chicken eggs is the culprit. A reduction in vaccine effectiveness occurs as the virus undergoes mutations while they are allowed to grow within the chicken eggs.

In general, manufacturing of flu vaccines involves the use of proteins originating from the external layer of destroyed flu viruses. The process prepares the immune system to identify and react to the virus as it enters the body. However, the H3N2 flu strains do not adapt to the egg cells. To bind with the cells, it develops a mutation that eventually integrates into the vaccine.

The mutation is a necessary step. Without the mutation, the flu virus will not grow unless they mutate, explained lead researcher and associate professor of microbiology at Perelman School of Medicine University of Pennsylvania Scott Hensley.

Last year's mutation was quite significant to cause a disparity between the dominant H3N2 virus and the vaccine.

Hensley lamented that while the virus could grow in canine or insect cell cultures, only those vaccines catering people with egg allergies undergo such manufacturing process. Hensley calls for an evaluation of the manufacturing process for these vaccines since many experts are already aware of this mutation.

Paul Offit, director of Vaccine Education Center at Children's Hospital of Philadelphia, echoed Hensley's sentiments. Offit stressed that while it is expensive to manufacture a new vaccine, pharmaceuticals must make the necessary steps to offer new and effective vaccines. He added that the companies must also ensure to conduct an extensive testing before changing their growth medium.

The Need To Vaccinate

According to Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, the ineffectiveness of the vaccines should not discourage people to get their flu shots. Fauci also called on pharmaceutical companies to hasten the availability and delivery of flu vaccines.

"Every time there's a pandemic we always find we are behind the eight ball in terms of never getting the vaccine ready before it peaks," Fauci said.

Pharmaceutical companies are not willing to spend cash and their resources on producing flu vaccines because of the low compliance of the public. Center for Disease Control recommends yearly vaccine for those aged 6 months and above, but only half of the population comply. Parents are highly encouraged to follow recommendations.

"The last thing we want is for readers to think this is some kind of anti-vaccine story," Hensley said. "Thirty-four percent effectiveness is better than zero."

The study is published in Proceedings of the National Academy of Sciences on Nov. 6.

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