Mains-GS-3-Technology
The human challenge trials involve intentionally infecting volunteers with the coronavirus. It is being promoted in order to speed up the process of preparing a vaccine.
How are vaccines usually developed?
1. In most regulatory regimes, vaccines take several years to develop, and their development typically proceeds through three phases of clinical trials.
2. In Phase 1, small groups of people receive the trial vaccine.
3. During Phase 2, the clinical study is expanded and the vaccine is given to people who have characteristics (such as age and physical health) similar to those for whom the new vaccine is intended.
4. In Phase 3, the vaccine is given to several thousand people and tested for efficacy and safety. During this phase, participants either receive the vaccine or a placebo.
5. The efficacy of the vaccine is determined by comparing the prevalence of infection in the group that was administered the vaccine with the one which received a placebo. The hypothesis that those in the vaccine group will be infected significantly less is thus tested.
What are human challenge trials?
1. Under human challenge trials, participants of both the vaccine and placebo group upon consent are deliberately exposed to the infection – “challenged” by the disease organism.
2. It could save time in developing a Covid-19 vaccine as researchers would not have to wait for participants to contract the infection under real-world conditions.
3. Controlled human challenge trials of SARS-CoV-2 vaccine candidates could accelerate the testing and potential rollout of efficacious vaccines.
4. Replacing conventional Phase 3 testing of vaccine candidates saves many months from the licensure process, making efficacious vaccines available more quickly.
5. Such testing would also require significantly less number of people than regular Phase 3 trials that require thousands of volunteers.
Why is it controversial?
1. Human challenge trials are usually carried out in developing medications for diseases that are considered less lethal and have been better understood by scientists over the years, such as malaria.
2. Such trials for Covid-19, a potentially deadly disease for even those who are less at risk is being questioned.
3. The World Health Organization (WHO) also had observed that Human challenge studies can appear to be in conflict with the guiding principle in medicine to do no harm.
Which are the ethical issues to be considered?
1. Historical examples of human exposure studies would be considered unethical by current standards.
2. It is essential that challenge studies be conducted within an ethical framework in which truly informed consent is given.
3. Human challenge studies should be undertaken with abundant forethought, caution, and oversight.
4. The value of the information to be gained should clearly justify the risks to human subjects.
5. Information to be gained should clearly justify the risks to human subjects.
Source: Indian Express