Today, the journal “Vaccine” published an article that could overturn one of the key principles of Good Distribution Practice – that vaccines must be kept cold.
The importance of the cold-chain has long been a challenge for those delivering vaccines to the most remote and hot regions of the world. Not only is there a high cost involved in maintaining controlled temperatures of typically 2-4°C, sometimes the timing of application makes it impractical.
For example, a baby should be given the vaccine for Hepatitis B within 24 hours after birth. Because it may not be possible to guarantee a supply of chilled vaccine in that key window, many African babies go unvaccinated.
In the new study, 155,000 people in Benin were successfully vaccinated against meningitis with the vaccine, MenAfrivac, kept in temperatures of up to 39°C. The really interesting point is that this was not some radical new formulation. The vaccine was essentially identical to the versions that are supposed to be kept chilled to remain effective.
This finding could potentially allow millions of people in most isolated regions of the so-called meningitis belt to be vaccinated for the first time.
Could the same be true of other vaccines?
“The method has potential for a lot more vaccines,” according to Patrick Lydon, a health economist at the WHO. Several other vaccines are anecdotally believed not to require cold chain – these include: Hepatitis B, yellow fever and HPV.
For MenAfrivac alone, the campaigns planned until 2016 could save as much as £12 million by dispensing with cold chain. In some cases, around half of the entire cost of distribution is taken up with keeping the vaccines in freezers, cold boxes, and ice packs.
So what next?
The first step would be to test and re-licence existing vaccines to be shipped without cold-chain requirements. The second, would be to encourage firms to develop new drugs that can be shipped without temperature control.
I’m not suggesting that conventional concepts of the cold chain be thrown out of the window.
We know that many vaccines have the potential to denature under the wrong conditions rendering them useless. But maybe this research will help some developers proceed with fewer assumptions about safe distribution techniques?
