For the successful development of a vaccine to be used against a pathogen, it is necessary that the surface antigens of the pathogen stay the same
Explain the development of a vaccine
Each vaccine under development must first be screened and evaluated to decide which antigen should be employed to elicit an immunological response.
- This preclinical phase is carried out without the use of human subjects.
- An experimental vaccination is initially tested in animals to determine its safety and potential for disease prevention.
- If the vaccine elicits an immunological response, it is subsequently examined in three stages in human clinical trials.
Phase 1
A limited number of volunteers are given the vaccine to test its safety, ensure that it produces an immunological response, and select the appropriate dosage.
- Vaccines are often tested at this phase on young, healthy adult volunteers.
Phase 2
The vaccine is then administered to hundreds of volunteers in order to test its safety and capacity to elicit an immunological response.
- Participants in this phase share similar characteristics (such as age and gender) with those for whom the vaccination is intended.
- During this phase, several trials are routinely conducted to examine various age groups and vaccine formulations.
- A non-vaccinated group is generally included in the phase as a comparative group to assess if the changes in the vaccinated group are due to the vaccination or occur by coincidence.
Hence, the correct answer is option A
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