As a result, in the coming months, millions of the most vulnerable people in the U.S. will receive a vaccine that protects them against the disease.
This is good news, but it does pose an ethical dilemma for researchers conducting ongoing clinical trials of these and other COVID-19 vaccines. More than 180 candidate vaccines against the disease are in development, with at least 12 in phase 3 clinical trials.
Clinical trials investigate whether or not a vaccine is safe and effective by giving it to around half of all the volunteers (and giving a placebo vaccination to the rest). The trials are “double blind,” meaning that neither the participants nor the researchers know which participants received the vaccine and which received the placebo.
According to guidance issued by the FDA in June 2020, in the event of a COVID-19 vaccine being judged safe and effective, there may be a case for “unblinding” trials and offering the vaccine to those who received the placebo.
Given that the treatment options remain limited for anyone who develops a severe, life threatening case of COVID-19, it may be in the best interests of trial participants to receive one of the two proven vaccines as soon as possible.
Is it, therefore, unethical to continue placebo-controlled clinical trials of these two vaccines? Also, should researchers use placebos in trials of other COVID-19 vaccines?
Bioethicists at the National Institutes of Health (NIH) Clinical Center in Bethesda, MD, address these complex ethical issues in an opinion piece in the latest issue of the journal Science.
The authors emphasize that vaccine researchers need to take other factors into consideration when they decide whether or not to continue trials as originally planned.
They write that even if early results have found some vaccines to be safe and effective, continuing to conduct trials may bring further benefits for society.
For example, due to the challenges of manufacturing sufficient quantities as rapidly as possible, several different vaccines may be necessary to meet global demand. Also, in parts of the world with poor health infrastructures, vaccines that need to be stored and transported at very low temperatures — as is the case for the Pfizer-BioNTech vaccine — are impractical.
In addition, some vaccines may be more effective than others at protecting particular groups, such as older people or those with comorbidities.
“This highlights the potential social value of conducting additional trials after one or more vaccine candidates are found to be safe and efficacious,” they write.
Even after the FDA grant EUA to a vaccine, conducting further research may provide additional information and reassurance about its safety and efficacy before offering it to millions of people.