A human challenge study, otherwise known as a controlled human infection trial, is a type of clinical trial for a vaccine (or other drug), in which participants are intentionally exposed to an experimental drug or an infectious agent.
The UK announced recently it will run a challenge trial for COVID-19, making it the first country in the world to do so. Healthy young volunteers will be deliberately infected with SARS-CoV-2, the virus that causes the disease, COVID-19.
According to a press release by the UK government, the human challenge study has received ethics approval, and will be conducted within the next month. The purpose of the study is to better understand the virus, testing the effectiveness of current vaccines and accelerating development of newer vaccines.
The UK is seeking up to 90 volunteers, 18-30 years old for the study. Participants “will be exposed to Covid-19 in a safe and controlled environment to increase understanding of how the virus affects people,” reads the press release.
In debating the ethics of the deliberately infecting people with a disease that has no hitherto known cure, the New York Times reports that scientists and bioethicists say the risk of coronavirus “seriously sickening or killing young, healthy volunteers — the sort of people who would be infected — is low enough as to be outweighed by the possibility of saving tens of thousands of lives.”
But the mere fact that there is no cure for this potentially lethal disease is itself unethical, critics of the human challenge trial contend.
“Whereas proponents of these studies suggest that such studies will accelerate the time to approve vaccines, the facts fail to support these claims. [Health Challenge Studies] to address SARS-CoV-2 face unacceptable ethics challenges, and, further, undertaking them would do a disservice to the public by undermining already strained confidence in the vaccine development process.”
Participants will not have previously received the COVID-19 vaccine, and will have tiny droplets of the SARS-CoV-2 virus inserted into their nostrils to assess the smallest amount of viral load needed to cause infection.
Gradually, the dose of the virus will be increased to determine the smallest amount of viral load that triggers infection in the majority of people. Researchers will measure viral shedding out of the participants’ noses to measure the amount of virus released by participants.
“Participants will then quarantine in a hospital for 14 days and be monitored daily by a medical team to determine how the immune system responds and whether certain factors influence transmission of the virus,” reports ChildrensHealthDefense.org.
Despite varying and emerging strains of the virus, researchers will use the version that has been circulating in the UK since the beginning of the pandemic.
Even vaccine makers are skeptical of this COVID-19 human challenge trial.
Interviewed by The New York Times, Dr. Paul Stoffels, chief scientific officer at Johnson & Johnson, said that he “would consider challenge trials only if a treatment became available” and that “traditional phase 3 trials would provide more safety information.”
As for Moderna’s top medical officer, Dr. Tal Zaks, he said, “We would hate to put people in harm’s way.”
Human challenge trials have been conducted for numerous diseases, including malaria, cholera, typhoid and influenza vaccines. But the COVID-19 study will be different because there is no “rescue therapy” to treat those who become infected and the disease is not self-limiting, the authors of the PNAS op-ed said.
Click here to read the full article at ChildrensHealthDefense.org.