The autism vaccine link--actually, the lack of linkage and the cost to public health--waddles on. (It has been particularly well covered in Spiked by Michael FitzPatrick, M.D.). Preventable diseases such as measles kill millions each year. New technology makes vaccination--especially in developing countries where refrigeration is not easily available--safer and more available.
Vaccines that do not have to be refrigerated could help protect millions more children in poor countries from major diseases. The “stable liquid” technology could also be used to produce vaccines that can be stockpiled in case of pandemics.
At the moment $200 to $300 million a year is spent in poor countries on the "cold-chain” – a process to keep vaccines refrigerated and protect them from extreme temperatures.
Despite this, nearly half the vaccines go to waste when the cold chain fails. The developer of the stable liquid technology, Cambridge Biostability in the UK, says that preventing this waste will enable 10 million more children a year to receive vaccinations at no extra cost.
The key to the technique is encasing the active ingredients in a vaccine in a sugary coat that preserves them at temperatures of up to 60°C. The coating is made from simple natural sugars such as raffinose and an amino acid, typically glutamine.
"They form a completely transparent, spherical glass-like ball about 3 micrometres in diameter," says Bruce Roser, chief scientist at Cambridge Biostability.
The tiny balls are then suspended in an inert liquid, which prevents any bacteria spoiling the vaccine. Calcium phosphate is also added to the balls to make them neutrally buoyant, so they do not float to the surface of the liquid or settle out. The company is currently using a perfluorocarbon liquid but because this chemical damages the ozone layer it is investigating alternatives.
The resulting vaccines can survive extreme heat and cold without any need for refrigeration. "You can keep the vaccine in the glovebox of your Land Rover in the Sahara," says Roser. When injected, the sugary balls dissolve, releasing the active ingredients, and the perfluorocarbon is eventually harmlessly exhaled.
Cambridge Biostability received £950,000 from the UK government on Tuesday to develop a heat-resistant combination vaccine against diphtheria, tetanus, whooping cough, a form of meningitis and hepatitis B. It is developing the vaccine together with Panacea Biotec in New Delhi, India.
For combination vaccines, the technology has another advantage. Each component can be coated before being mixed together, ensuring they cannot interfere with each other as sometimes happens in conventional vaccines.
The balls can also be tweaked to make them dissolve at different rates, allowing booster doses that would normally have to be given separately to be given in a single injection, for example.
Roser's ultimate aim is to produce a single heat-resistant vaccine against all 12 major childhood diseases targeted by the World Health Organization (WHO). The company will also produce vaccines against potential bioweapons for the US government, to be stockpiled.
The World Health Organization (WHO) says the approach is promising. The key question for it is whether the advantages outweigh the costs, such as funding the clinical trials that will be needed and evaluating the safety of alternatives to perfluorocarbon.
"Sometimes we must look beyond the technology and ask whether it will become too expensive," says Martin Friede, a vaccine specialist at the WHO's Geneva’s headquarters.