Waiting on a Better Vaccine
Feb 04, 2013

Today I came across an article that may seem insignificant to some.  It highlighted a highly anticipated study of the first new tuberculosis vaccine in 90 years, only to reveal the disappointing news that the vaccine offered no added benefit over the current vaccine.
So, why is a failed vaccine trial for tuberculosis – something we don’t even routinely vaccinate for in the United States – news at all?
To me, it is a reminder of why we must continue with vaccine research and development.  As vaccine critics complain about the efficacy of vaccines, and we see epidemic cases of flu and pertussis, we’re often reminded that certain vaccines are not as effective as we would like for them to be.  But we can only make them better with scientific advancements and continued research.
And despite what many vaccine critics believe, improving vaccine efficacy is something that scientists and vaccine manufacturers are working hard to improve on.  The following excerpt from today’s Reuters article explains:

The current TB vaccine, known as Bacille Calmette-Guérin, or BCG, was developed in 1921, and is given routinely to babies in countries with high rates of TB to prevent severe disease.  However, protection wears off in just a few years, and BCG does nothing to protect against the most common form of tuberculosis that invades the lungs of adults and adolescents, and can be transmitted through coughing and sneezing.

As we see in this example, trials are conducted on new vaccines, not just to determine safety, but also to ensure efficacy.   This particular research determined that the protection seen in the infants was much lower than had been seen in adults who had tested the vaccine, and they plan to look more closely to understand why.
The important thing to recognize is that even failed trials offer critical information that may help lead to important advancements in the future.

This is the first efficacy trial of a new TB vaccine since Bacille Calmette-Guérin, a significant step in itself, and there is much that we and others can learn from the study and the data it produced.  

And, in case anyone should think differently, not all diseases are the same, and the vaccines created to reduce the effects of these disease often require different methods and approaches.  As the Reuters article elaborates,

With many other infectious diseases, scientists can rely on animal models and protective markers in the blood known as correlates of protection to predict whether a vaccine will work in people. This is not that case with TB, an ancient disease that hides out in the cells of their human hosts.  As a result, TB vaccines must be tested in large clinical trials in people, a large and costly gamble.

Despite these challenges, scientists are continually trying to develop more effective vaccines in order to save lives.  Sadly, the Reuters article states that the global TB epidemic infects 9 million people annually and kills 1.4 million.  This explains why Dr Ann Ginsberg of Aeras, a non-profit biotech based in Rockville, MD, says it would be “a huge mistake for the world to get discouraged by this and give up.”   She goes on to say that TB is “far too urgent a problem” and the current tools “far too inadequate” to address the global TB epidemic.  She says,

“The one thing that could change the game on the TB epidemic is to have safe, affordable and effective vaccines.”

So, even despite the high hopes for this particular vaccine, this failed trial is not a complete failure.  It simply marks one step in the development of something better.  Meanwhile, there are other TB vaccines in development and in large-scale trials.  Let’s hope that they are more successful and that they ultimately result in a more effective vaccine that can offer the world better protection from such a serious and deadly disease.

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