Vaccines include either tiny pieces of the organism that is carrying the disease or the blueprint to create those tiny pieces. Moreover, some other ingredients like antigen, stabilisers, diluent, surfactants, adjuvants, residuals and preservatives, and all are tested for safety during the development of the vaccine. These ingredients have been used in numerous vaccines for several decades.
Development of vaccines
A vaccine has to undergo a rigorous and extensive testing phase as well as screenings so that the researchers can identify the antigen that would stimulate the desired immune response. Animals are used for this testing. Once the vaccine evokes the desired immune response among animals, it is then moved to the stage of being tested on humans. These are called clinical trials and are conducted in three phases. In the first one, a few volunteers are administered the dosage to check for the immune response and also to ascertain the correct dosage. After this, several hundreds of volunteers participate in the second phase of trials, during which several formulations of the vaccine are administered and multiple trials are conducted. At the same time, a group is given a placebo to ensure that the immune response generated among the group being vaccinated is indeed due to the vaccine.
The last phase has a much larger group of participants, and the study is usually conducted in various countries and at multiple sites within a country itself.
The researchers and officials of every country then review the data that is obtained from these trials to make a decision on the authorisation of the vaccine.
Vaccines and their packaging
Vaccines are manufactured in bulk and stored in glass vials, after which they undergo careful packaging so that they can be safely kept in cold storage and transported. The packaging process has been developed in a manner to ensure that extreme temperatures and risks of global transportation can be withstood. Usually, vaccines are stored between 2 degrees and 8 degrees Celsius, as they can be rendered ineffective if they become too cold or too hot. Some new vaccines are however stored at ultracold temperatures of -70 degrees Celsius.
Shipment of vaccines
Vaccines are kept safe in specialised equipment, which upon reaching the desired country is taken to the cold rooms at warehouses from the airports with the help of refrigerated trucks. From there, portable iceboxes are required to transport the vials to regional centres.