Solid oral vaccines have proven to be more stable and less likely to freeze ; this stability reduces the need for a `` cold chain '' : the resources required to keep vaccines within a restricted temperature range from the manufacturing stage to the point of administration , which , in turn , will decrease costs of vaccines . Oral vaccines are likely to be solid which have proven to be more stable and less likely to freeze ; this stability reduces the need for a `` cold chain '' : the resources required to keep vaccines within a restricted temperature range from the manufacturing stage to the point of administration , which , in turn , will decrease costs of vaccines .