The coronavirus pandemic is still actively and aggressively spreading across the globe, with more than 21.55 million people infected. Though more than a hundred candidate vaccines are underway to combat the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the coronavirus disease (COVID-19), only six candidates are undergoing clinical trials.
Now, a team of scientists in the United States plans to create a coronavirus strain that can be used for human challenge trials, a controversial type of study wherein health volunteers would be vaccinated and intentionally infected with the virus.
Human challenge trials accelerate the process of testing the safety and efficacy of a vaccine. Still, if the vaccine is ineffective, the participants will have to face the circumstances and effects if they contract the novel coronavirus.
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The work is still preliminary
The country's top infectious disease expert, Dr. Anthony Fauci, has confirmed that scientists at the National Institute of Allergy and Infectious Diseases (NIAID) are currently working on manufacturing a strain of coronavirus that could be used in human challenge trials of a COVID-19 vaccine.
As the director of NIAID, Fauci dubbed the approach as the nation's "Plan D," and the work is still preliminary. If the situation calls for it, a human challenge trial would be done in a matter of months. The government is now prioritizing randomized clinical trials of various vaccine candidates, including vaccines developed by Moderna, AstraZeneca, and Pfizer.
The agency, however, has started to manufacture the coronavirus strain. In typical clinical trials, healthy volunteers either receive the vaccine or a placebo and their health status is followed for months. On the other hand, in human challenge trials, the volunteers are exposed to the virus to test the vaccine has triggered an immune response against the virus.
Decision by the end of 2020
The approach has utilized in the past for other diseases such as malaria, typhoid, influenza, cholera, and dengue fever. In the U.S., some advocacy groups, such as 1DaySooner, support challenge studies for the coronavirus infection but have been faced with controversial reactions because of how severe the infection can be, and its effects are not fully understood.
"Should there be a need for human challenge studies to fully assess candidate vaccines or therapeutics for SARS-CoV-2, NIAID has begun investigations of the technical and ethical considerations of conducting human challenge studies," the agency statement said.
Drug firms, including Johnson & Johnson and AstraZeneca, said they would consider performing human challenge trials to determine if their candidate vaccines are effective if needed. This type of vaccine trial will not hasten the development of a vaccine, which is still about two years away before being approved.
The NIAID further emphasized that human challenge trials should not replace large-scale, Phase 3 trials. However, the health agency plans to decide by the end of 2020, when the last stage human trials will report their results, to determine if challenge tests are required.
Vaccines on their way
The World Health Organization (WHO) reports that more than a hundred experimental vaccines were developed to combat SARS-CoV-2. Of these, 138 are in their preclinical evaluation, while 29 are now being trialed in various phases.
Six vaccines are now in the last phase of human trials, which were created by the University of Oxford/AstraZeneca, Sinovac, Wuhan Institute of Biological Products/Sinopharm, Beijing Institute of Biological Products/Sinopharm, Moderna/NIAID, and BioNTech/Fosun Pharma/Pfizer.
The coronavirus global toll
The coronavirus disease is still wreaking havoc across the globe, with 188 countries and territories affected. So far, the number of confirmed cases has topped 21.55 million people, with at least 772,000 deaths. The United States has the highest number of infections, with a staggering 5.39 million confirmed cases and more than 169,000 deaths.
Brazil and India follow with more than 3.31 million and 2.58 million cases, respectively. Brazil has a death toll of more than 107,000. Meanwhile, Russia's confirmed cases near one million, while South Africa, Peru, Mexico, and Colombia report more than 587,000, 525,000, 517,000, and 456,000 cases, respectively.