The story of workers who are vaccinated in Brazil 3:30
Editor's Note: Robert Klitzman is a professor of psychiatry and director of Columbia University's master's program in bioethics. He is the author of "Designing Babies: How Technology is Changing the Ways We Create Children." The opinions expressed in this comment are solely those of the author. .
(CNN) - As scientists compete to develop a covid-19 vaccine, thousands of people have expressed interest in participating in clinical trials that expose them to the virus. Many of these people are eager to help in order to save lives and are willing to take any potential risk.
But should they be so eager to participate?
Vaccines are typically developed over the course of several stages, beginning with tests on Petri dishes and animals. The small fraction of these tests that show some promising results then enter various phases of human trials, where researchers administer the vaccine to an increasing number of people while monitoring the dose and evaluating side effects and efficacy.
In Phase 3 (the last phase before the FDA approves it), the researchers separate the participants into two groups and administer the vaccine to one group while giving the other a placebo.
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Researchers generally wait several months while participants lead their lives, go to work, see family members, or take public transportation. If fewer people who received the vaccine than those who received the placebo end up infected, it is considered effective.
Because doctors have an ethical duty to minimize harm, they generally avoid deliberately infecting people with a virus. But the usual process of waiting to see how many of the participants are naturally infected takes a long time.
And if the trials are conducted in a place where community spread is low, participants in both groups will never be exposed to the virus, and researchers would have a hard time determining if the vaccine works.
Given the urgency of finding a safe and effective covid vaccine, the researchers, in some cases, skip animal testing. Human challenge or "controlled infection" trials have also been proposed, which would allow researchers to intentionally expose all participants to the virus to assess the effect of the experimental vaccine more quickly.
An organization called 1Day Sooner, which advocates the use of human challenge trials in the development of a covid-19 vaccine, asks people (especially those who are young and do not have underlying health conditions) to enter their Names online and declare that you are willing to volunteer to participate in the trial.
The idea has garnered considerable support, with more than 32,000 people expressing interest, according to the 1Day Sooner website. The group also organized an open letter to the director of the National Institute of Health, Dr. Francis Collins, highlighting the importance of controlled infection trials. More than 150 people have signed it, including 15 Nobel laureates and other experts and academics.
On paper, this approach seems straightforward and full of potential, as the world is desperate to develop a covid-19 vaccine. But it is essential that the process, together with the final product, be as safe as possible, especially given the distrust of science in this country and the growing anti-vaccine movement. This novel study design poses several important problems that have yet to be resolved.
More than 165 covid-19 vaccines are currently under development. No one knows which, if any, will work. Vaccines generally take more than a decade to develop; Scientists generally test many possibilities to find one that is successful.
Overall, only about 14% of vaccines entering phase 1 clinical trials end up being approved. But that success rate is based only on studies that have published data: Many pharmaceutical companies and researchers don't disclose the data when their experimental products don't work. The actual odds of success are undoubtedly much lower.
If a controlled infection test for a vaccine fails after all participants have been infected, some are likely to become seriously ill and die. According to data from the United States Centers for Disease Control and Prevention, from mid-February to mid-March, up to 20.8% of people aged 20 to 44 years infected with covid required hospitalization, 4, 2% entered the intensive care unit and 0.2% died.
It is unclear whether or not controlled infection trials will be implemented. Proponents of these trials say they may need about 100 participants for each study. If the researchers adopted this approach during 20 studies, 2,000 people would become infected with covid.
Assuming that none of the vaccines worked, it is estimated that 416 of these participants might need hospitalization, 84 might need an ICU, and four could die, according to CDC data earlier this year. If one of the 20 test vaccines works, only 100 participants would be protected, while 1,900 would be infected.
Most vaccine trials are designed to assess whether the product leads people to develop antibodies, not whether the vaccine actually prevents infection. Even if an experimental vaccine causes someone to develop antibodies, they may not successfully activate all of the body's immune system components to effectively attack the virus.
To top it off, the researchers haven't determined how long the covid antibodies will last, how many antibodies will protect people from infection, and whether reinfection is possible. While willing volunteers, many of them young adults, may think they are at little or no risk in controlled infection trials, some are putting themselves at greater risk than they think.
A vaccine can also be only partially effective and could cause significant side effects. It could, for example, create antibodies in only 50% or 60% of participants and cause serious illness in 10%.
Given the tremendous devastation of covid, the U.S. Food and Drug Administration has said it will approve a vaccine that prevents the disease or lessens its severity in at least 50% of those who receive it.
It is important to remember that in 1976, a swine flu vaccine was approved and eventually administered to some 45 million Americans, of whom more than 450 developed Guillain-Barré syndrome, a rare neurological disorder in which the immune system The body mistakenly attacks the nervous system.
Since then, that incident has helped fuel the anti-vaccine movement.
Pharmaceutical companies developing the vaccine will also no doubt seek to benefit from it. Remdesivir, an antiviral drug that has shown signs of speeding recovery in moderately ill patients with covid-19 pneumonia, costs between $ 2,000 and $ 3,000 per person for a five-day course of treatment.
While advocates of controlled infection trials argue that participants would save millions of lives, that would be the case only if a vaccine proves to be safe and effective, not to mention accessible to millions of people.
Unfortunately, given the increasing costs of medications in the United States, pharmaceutical companies that end up developing a successful vaccine can charge a significant amount of money for it.
Although the Trump government recently arranged a $ 1.9 billion agreement with Pfizer for 100 million doses of a vaccine, with the right to purchase an additional 500 million, that experimental vaccine is just one of many currently under investigation.
Proponents of challenge studies have also largely ignored the question of whether participants (or their families) will be compensated if they end up with long-term medical problems or die as a result of the trial.
And while participants are generally paid to participate in conventional vaccine trials, subjects in controlled infection trials would likely receive an even higher payment, raising concerns that this will attract people who are in financially vulnerable positions to take greater risks.
The country faces an economic crisis and there is a long and dark history of researchers disproportionately experimenting on poor and colored people. Just look at the case of Henrietta Lacks, a black woman whose cells were removed from a tumor on her cervix without her knowledge and used in medical research for decades without her family's knowledge.
While we should not automatically reject the possibility of human challenge trials, given the number of lives that could be saved with an early vaccine, we must proceed with great caution.
If we embark on these trials, researchers should be even more selective about which experimental vaccines to use. Pharmaceutical companies should also commit to making the vaccine, if approved, affordable for millions of people.
If researchers embark on controlled infection trials, they should administer the vaccine and infect only a handful of participants at a time, and verify whether it is effective before administering it to additional subjects to minimize any potential harm.
Informed consent and robust guidelines for all participants are crucial, and investigators should question each participant to ensure they fully understand the potential risks.
We all want a safe, effective and widely available vaccine, but researchers must ensure that the safety of participants is also fully considered.
Coronavirus vaccine