Anthony Fauci, well known infectious diseases specialist and a senior adviser to US President Donald Trump on COVID-19 has said that he is doubtful about the safety of human challenge trials. Fauci, Director of the National Institute of Allergy and Infectious Diseases, USA speaking at a vaccine symposium hosted by the Indian Council of Medical Research (ICMR) on Thursday said, "As the full health impact of the virus is not yet understood, putting people at risk is not necessary and essential according to me."
This event was held in collaboration with the London School of Tropical Hygiene, the Vaccine Confidence Project, and the Global Health Security Network.
This statement by Fauci comes at a time that the Oxford-AstraZeneca inactivated adenovirus vaccine is planning to follow this method. In human challenge trials, participants will be deliberately exposed to the SARS-CoV-2 virus after being administered the vaccine to see if any antibodies act against the virus. The ethics and safety of these human challenge trials were debated by many eminent national and international scientists during the symposium.
Human Challenge Trials
But many scientists disagreed with Fauci's statement on human challenge trials.
Adrian Hill, Director of the Jenner Institute in Oxford University which has designed the Oxford vaccine, defended human challenge trials by putting forth that the vaccine was following both the Phase III and human challenge trials. He further elaborated that young individuals were willing to participate in these human challenge trials. The human challenge trials will reduce the time taken for understanding the safety of the vaccines.
"For treating individuals that do get infected after exposure, many trials across the world have shown medicines that are effective against the SARS-CoV-2 virus," Dr. Hill said even as he gave examples of how human challenge trials have been followed for diseases like malaria.
Highlighting the advantages as well as disadvantages of human challenge trials, Stanley Plotkin from University of Pennyslvania said, "Advantages of Human Challenge Trials include protection, developing an immune response, being able to compare reactions head to head, and use as effective emergency use. The safety of the individuals, choosing only healthy individuals with low risk and them not being exclusive as high risk individuals will be kept out are the disadvantages." He also said that in the current times, as a vaccine is needed, such conversations should not stall vaccine development. Both the Phase III and human challenge trials can be carried out together
In Phase III trials, the blood of the participants is tested for antibodies without exposure to the virus. The Oxford vaccine has conducted Phase III trials with ten thousand people in UK, four thousand in Brazil, two thousand in South Africa and is planning a trial for thirty thousand in the USA.
Vaccine Nationalism And Equitable Distribution
As countries such as United States, Britain and the European Union have signed deals for large scale vaccines with Pfizer (PFE.N), BioNtech (22UAy.F), AstraZeneca (AZN.L) and Moderna (MRNA.O), issues of vaccine nationalism and equitable distribution have arisen in many scientific conversations. Fauci further discussed the financial risks each country was taking to boost the vaccine production and hoped that considering the high stakes and risks, the vaccines would be safe and effective.
Low-middle income countries may bear the brunt of not receiving vaccines if these countries monopolise to receive the first batch of doses. To avert such situations and ensure equitable distribution, the World Health Organisation with the Global Alliance for Vaccines and Immunisation (GAVI), the Coalition for Epidemic Preparedness Innovations (CEPI) have initiated COVAX and Access to COVID-19 Tools (ACT) Accelerator, said Dr. Peter Piot, London School of Hygiene and Tropical Medicine.
Issues of pricing of the vaccines were raised by Dr. Yogesh Jain from Jan Swasthya Sahyog and Prof. Indrani Gupta, Institute of Economic Growth, India. They questioned whether the vaccine will be a public good or will be entrenched in profiteering. Experts said they would have to wait till the vaccines are available to discuss this issue.