What is Human Challenge Trials
Publishing date- 2 May 2020
Image credits- canva.com
Medical researchers all over the world are fighting at two fronts-
1.) THERAPIES
2.) VACCINES
Therapies means the medicine which is
given to an infected person to cure the disease.
Vaccines is given to a non-infected peraon to prevent them from the disease.
There are already atleast 254 therapies and 95 vaccines related to COVID-19 being explored.
For example, drugs like Remdisivir and hydrochloroquinone are being tried as a potential therapy to cure infected person.
Therapies are being tried with existing medicines while for vaccines, one has to start from scratch.
So, it takes more time to find the vaccine for COVID-19.
Image credits- canva.com
CORONAVIRUS
● What is HUMAN CHALLENGE METHOD
The Human challenge method, which involves intentionally infecting volunteers with the novel coronavirus, is being promoted in order to speed up the process of preparing a vaccine.
Now, development of vaccine takes a long process.
There are different stages of the development cycle of a vaccine.
Some general stages are-
1.) Exploratory stage
2.) Pre-clinical stage
3.) Clinical development
4.) Regulatory review and approach
5.) Manufacturing
6.) Quality control
• The Human Challenge Method is related to clinical development method.
The first two stages are mostly paperworks.
Vaccine is tested on a human being during clinical development stage.
● Clinical stage
Phase 1- small groups of people receive the trial vaccine
Phase 2 - the clinical study is expanded and the vaccine is given to people who have characteristics such as age and physical health, similiar to those for whom the new vaccine is intended
Phase 3 - vaccine is given to several thousand people and tested for efficiency and efficacy and safety
● How do we know whether the vaccine succeded ?
During the third phase , participants either receive the vaccine or a placebo ( fake vaccine)
The efficacy of the vaccine is determined by comparing the prevalance 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.
Normally, this entire process is very long.
For a rough estimate,
If research starts for a disease in 2020, then it will take nearly 15 years to find its vaccine.
NOTE - On an average, only 10% of the vaccine tested become successful.
Mostly gets disqualified after phase 1, some after phase 2 and some even after completing the trial process.
• There are some vaccines in the list below which shows how much time did they take for completion:-
1.) Varicella - 28 years
2.) Flumist - 28 years
3.) Human papillomavirus - 15 years
4.) Rotavirus - 15 years
5.) Pediatric combimation - 11 years
6.) COVID-19 - 18 months (very less)
Image credits- canva.com
ROTAVIRUS
The time interval set for COVID-19 vaccine is very less as compared to others.So, each stage must be accelerated during its development.
We can reduce the time of manufacturing and approval but we cannot reduce the time it takes for clinical trials.
● What are the problems with clinical trials
Clinical trials almost never succeed less than 10% of drugs that enter clinical trials are ever approved by the Food and Drug Administration.
• We have never released a coronavirus vaccine for humans before.
• Our record for developing an entirely new vaccine is atleast 4 years.
● What are Human Challenge Trials
Under human challenge trials, participants of both the vaccine group and placebo group upon consent are deliberately exposed to the infection.
Thus, they are ''challenged'' by the disease organism.
Benefits - saving of valuable time
No wait for participants to contract the infection in real-world conditions.
The human challenge trials are done to reduce the time of phase-3 and also these trials need lesser no. of peoples as compared to phase-3.
But, the biggest concern about human challenge trials is ethical issues.
Whether, it is right to infect a healthy person intentionally with the disease just for vaccine development.
In fact, there is very important and most fundamental principle in medical fraternity
" Primum non nocere"
means, first do not harm.
The Ethical issues
Image credits- google photos
Human challenge studies has been conducted over hundreds of years and have contributed vital scientific knowledge that has lead to advances in the development of drugs and vaccines.
While human challenge trials are not new, they are usually carried out in developing medications for diseases which are considered less lethal, for which 'therapeutic treatment' is available and have been better understood by scientists over the years , such as malaria.
When conducted, human challenge studies should be undertaken with abundant forethought, caution, and oversight.
The value of the information to be gained should clearly justify the risks to human subjects.
Thank you
Jai Hind🙏🙏🙏
Medical researchers all over the world are fighting at two fronts-
1.) THERAPIES
2.) VACCINES
Therapies means the medicine which is
given to an infected person to cure the disease.
Vaccines is given to a non-infected peraon to prevent them from the disease.
There are already atleast 254 therapies and 95 vaccines related to COVID-19 being explored.
For example, drugs like Remdisivir and hydrochloroquinone are being tried as a potential therapy to cure infected person.
Therapies are being tried with existing medicines while for vaccines, one has to start from scratch.
So, it takes more time to find the vaccine for COVID-19.
CORONAVIRUS
● What is HUMAN CHALLENGE METHOD
The Human challenge method, which involves intentionally infecting volunteers with the novel coronavirus, is being promoted in order to speed up the process of preparing a vaccine.
Now, development of vaccine takes a long process.
There are different stages of the development cycle of a vaccine.
Some general stages are-
1.) Exploratory stage
2.) Pre-clinical stage
3.) Clinical development
4.) Regulatory review and approach
5.) Manufacturing
6.) Quality control
• The Human Challenge Method is related to clinical development method.
The first two stages are mostly paperworks.
Vaccine is tested on a human being during clinical development stage.
● Clinical stage
Phase 1- small groups of people receive the trial vaccine
Phase 2 - the clinical study is expanded and the vaccine is given to people who have characteristics such as age and physical health, similiar to those for whom the new vaccine is intended
Phase 3 - vaccine is given to several thousand people and tested for efficiency and efficacy and safety
● How do we know whether the vaccine succeded ?
During the third phase , participants either receive the vaccine or a placebo ( fake vaccine)
The efficacy of the vaccine is determined by comparing the prevalance 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.
Normally, this entire process is very long.
For a rough estimate,
If research starts for a disease in 2020, then it will take nearly 15 years to find its vaccine.
NOTE - On an average, only 10% of the vaccine tested become successful.
Mostly gets disqualified after phase 1, some after phase 2 and some even after completing the trial process.
• There are some vaccines in the list below which shows how much time did they take for completion:-
1.) Varicella - 28 years
2.) Flumist - 28 years
3.) Human papillomavirus - 15 years
4.) Rotavirus - 15 years
5.) Pediatric combimation - 11 years
6.) COVID-19 - 18 months (very less)
ROTAVIRUS
The time interval set for COVID-19 vaccine is very less as compared to others.So, each stage must be accelerated during its development.
We can reduce the time of manufacturing and approval but we cannot reduce the time it takes for clinical trials.
● What are the problems with clinical trials
Clinical trials almost never succeed less than 10% of drugs that enter clinical trials are ever approved by the Food and Drug Administration.
• We have never released a coronavirus vaccine for humans before.
• Our record for developing an entirely new vaccine is atleast 4 years.
● What are Human Challenge Trials
Under human challenge trials, participants of both the vaccine group and placebo group upon consent are deliberately exposed to the infection.
Thus, they are ''challenged'' by the disease organism.
Benefits - saving of valuable time
No wait for participants to contract the infection in real-world conditions.
The human challenge trials are done to reduce the time of phase-3 and also these trials need lesser no. of peoples as compared to phase-3.
But, the biggest concern about human challenge trials is ethical issues.
Whether, it is right to infect a healthy person intentionally with the disease just for vaccine development.
In fact, there is very important and most fundamental principle in medical fraternity
" Primum non nocere"
means, first do not harm.
The Ethical issues
Image credits- google photos
Human challenge studies has been conducted over hundreds of years and have contributed vital scientific knowledge that has lead to advances in the development of drugs and vaccines.
While human challenge trials are not new, they are usually carried out in developing medications for diseases which are considered less lethal, for which 'therapeutic treatment' is available and have been better understood by scientists over the years , such as malaria.
When conducted, human challenge studies should be undertaken with abundant forethought, caution, and oversight.
The value of the information to be gained should clearly justify the risks to human subjects.
Thank you
Jai Hind🙏🙏🙏
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