Researchers at McMaster University have invented a stable, affordable way to store fragile vaccines for weeks at a time at temperatures up to 40C, opening the way for life-saving anti-viral vaccines to reach remote and impoverished regions of the world.
The new method combines the active ingredients in existing vaccines with a sugary gel, where they remain viable for eight weeks or more, even at elevated temperatures.
The method creates light, durable, and compact doses that would be ideal for shipping Ebola vaccine, for example, to affected regions of Africa, the researchers say.
The process adds only marginal cost to preparing a vaccine and eliminates almost all the cost of transporting it – which can account for 80 per cent of the total cost of inoculation.
Combining the vaccines and the sugars – pullulan and trehalose – is almost as simple as stirring cream and sugar into coffee, the researchers say.
The storage technology was created by chemical engineers at McMaster, who had already demonstrated its effectiveness in other applications, such as an edible coating that can prolong the shelf life of fruits and vegetables.
To apply the technology to vaccines, the engineers collaborated with health sciences colleagues across campus who specialize in virology and immunology. Their work is published today in the journal Scientific Reports.
“This, to us, is the ultimate application of this technology,” said the paper’s lead author Vincent Leung, an assistant professor of Chemical Engineering. “
To imagine that something we worked on in the lab could one day be used to save people’s lives is very exciting.”
The invention is significant because it can replace the cumbersome “cold chain – constant storage at temperatures between 2C and 8C – which is currently necessary to keep anti-viral vaccines viable.
Vaccine Storage and Handling
There are few immunization issues more important than the appropriate storage and handling of vaccines.
The success of efforts against vaccine-preventable diseases is attributable in part to proper storage and handling of vaccines.
Vaccines exposed to temperatures outside the recommended ranges can have reduced potency and protection.
Storage and handling errors can cost thousands of dollars in wasted vaccine and revaccination.
Errors can also result in the loss of patient confidence when repeat doses are required.
It is better to not vaccinate than to administer a dose of vaccine that has been mishandled.
Vaccine management, including proper storage and handling procedures, is the basis on which good immunization practices are built.
Vaccines must be stored properly from the time they are manufactured until they are administered.
Assuring vaccine quality and maintaining the cold chain is a shared responsibility among manufacturers, distributors, public health staff, and health-care providers.
A proper cold chain is a temperature-controlled supply chain that includes all equipment and procedures used in the transport and storage and handling of vaccines from the time of manufacture to administration of the vaccine.
By following a few simple steps and implementing best storage and handling practices, providers can ensure that patients will get the full benefit of vaccines they receive.
Storage and Handling Plans
Every facility should have detailed written protocols for routine and emergency vaccine storage and handling and they should be updated annually.
These policies and procedures should be available in writing as a reference for all staff members and easily accessible.
A routine storage and handling plan provides guidelines for daily activities, such as:
- Ordering and accepting vaccine deliveries
- Storing and handling vaccines
- Managing inventory
- Managing potentially compromised vaccines
Every facility should also have an emergency vaccine retrieval and storage plan.
The plan should identify a back-up location where the vaccines can be stored. Considerations when choosing this site include appropriate storage units, temperature monitoring capability, and a back-up generator that can maintain power to the vaccine storage units.
Potential back-up locations might include a local hospital, pharmacy, long-term care facility, or the Red Cross.
There should be an adequate supply of packing materials and portable refrigerators and freezers or qualified containers and packouts on hand to accommodate the facility’s largest annual vaccine inventory (e.g., flu season).
A refrigerated truck may be needed to move large inventories of vaccine.
Power outages or natural disasters are not the only events that can compromise vaccine.
Forgotten vials of vaccine left out on the counter or doses of vaccine stored at improper temperatures due to a storage unit failure are other examples of how vaccines can be potentially compromised.
Protocols after an event will vary depending on individual state or agency policies. Contact the local or state health department immunization program (hereafter referred to as “immunization program”), vaccine manufacturer(s), or both for appropriate actions or guidelines that should be followed for all potentially compromised vaccines. Do not discard vaccines unless directed to by the immunization program and/or the manufacturer.
Maintaining the cold chain is a significant barrier to inoculating people in remote or poor regions of the world, where the infrastructure to refrigerate and transport vaccines smoothly may not be available.
“You can spend all kinds of money developing a vaccine, but if it is deactivated by high temperature an hour before you can give it to someone, it doesn’t matter,” says co-author Ali Ashkar, a professor of Pathology and Molecular Medicine specializing in immunology.
The cold-chain challenge is so great, the researchers say, that in some regions, vaccines must be transported by camels bearing solar-powered mini-refrigerators. There are some populations that never receive vaccines.
“If you can’t get vaccines to the places where people need them, there’s no point in having them,” says co-author Matthew Miller, an assistant professor in the Department of Biochemistry and Biomedical Sciences whose laboratory specializes viral pathogens.
Not being able to get vaccines to isolated areas makes it impossible to eradicate deadly viruses.
Unchecked, such viruses can devastate local populations and reach exposed pockets in more populated countries where religious, cultural or other concerns have diminished the proportion of vaccinated individuals.
Such a scenario has recently been playing out in in a measles outbreak in the US northwest and Vancouver, BC.
The new vaccine-storage method suspends the active components of a vaccine in a tiny one-dose container filled with a sugar-gel combination that dries to seal in the vaccine.
Later, clinicians reconstitute the vaccine with water and administer it to patients as they ordinarily would.
“Often, complex problems have simple solutions. It just takes the right team,” says Miller. “The best research comes from merging fields, when you do something with someone else that you couldn’t do alone.”
The researchers have proven the method to be viable using two sample vaccines – influenza virus and herpes simplex virus – to inoculate and test mice by exposing them to the viruses because the immune response of mice is similar to that of humans.
The materials in the storage medium are already approved by the US Food and Drug Administration, simplifying the path to commercialization.
“All the pieces are ready to go,” says co-author Carlos Filipe, chair of Chemical Engineering at McMaster. “It’s actually quite simple compared to the technology required to create a vaccine itself.”
The researchers are working with a commercial partner to get the technology to market.
Journal information: Scientific Reports
Provided by McMaster University