VZV VACCINE PROJECT
Perhaps the most widely known syndrome caused by VZV is chickenpox. Chickenpox is a highly contagious viral infection caused by a virus called varicella-zoster virus (VZV). VZV is a member of the herpes virus group. Similar to other herpes viruses it remains dormant in the body after initial infection and may cause a latent infection later in life. VZV remains in the dorsal root of sensory nerve ganglia and can result in a recurrent infection known as shingles. The symptoms of shingles are a skin rash, blisters and pain. The pain may continue even after the skin blisters and rash have healed.
Due to the fact that the viruses within varicella vaccine are so fragile it must be handled carefully. To maintain potency, the freeze-dried vaccine must be handled strictly according to the package insert eg. frozen at an average temperature of -50 to -15°C (-58 to +5oF) or colder until it is reconstituted for injection (though it can be stored for up to 72 hours at 2 to 8°C (36 to 46oF). The diluent is stored separately at room temperature or in the refrigerator and once reconstituted the vaccine is discarded if it is not used within 30 minutes in one case.
VACCINE EFFICACY LOSSES
In manufacturing, as soon as the vaccine is released from the cells where it is grown, the viral integrity begins to decline, this is demonstrated by a declining titre. There are several key points during production where losses frequently occur and prevention at any of these points will have significant effects on the vaccine yield:
Bulk vaccine exposed to less than optimal temperatures for the duration of the fill run.
The lyophilization process is a highly destructive process for many biologically active products, unless there are measures taken, typically by formulation, to offset and prevent this damage.
Distribution of vaccines is a common area in which a large portion of vaccine integrity/efficacy is lost. A significant reason for these losses are the occasional temperature excursions encountered during the distribution of vaccine to end users.
NEXT GENERATION VZV VACCINE
A vaccine addressing all of the above points would be very beneficial to manufacturers, purchasers, distributors and ultimately the recipients who would be assured that the vaccine would remain fully efficacious. The product that Stabilitech has developed offers solutions to all of the above points. In this vaccine, the OKA vaccine strain has been used. With our Therm-SB technology, it has been shown to have highly enhanced stability at room temperature for several hours with minimal loss of titre and suffers lower losses upon lyophilization than any published results. Additionally, once dried the virus demonstrates enhanced stability with minimal losses observed over at least 7 weeks at 25°C. Finally, upon reconstitution with Stabilitech’s excipient mixes the virus remains in a state of elevated stability excipients in the reconstituted mix.