The risky way to speed up a coronavirus vaccine
发布时间 2020-08-12 12:00:13 来源
摘要
A Covid-19 vaccine could take a long time. Some scientists are proposing a controversial plan that could get us one faster.
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With thousands of people dying of Covid-19 every day, the sooner a vaccine can be deemed safe and effective, the better. But vaccine development is a lengthy process that isn’t easy to rush, and that’s in part because of the final step in testing any vaccine: the phase III trial. Phase III requires tens of thousands of volunteers, each of whom get either a placebo or an experimental vaccine. The problem is the next part: Vaccine developers have to wait until a statistically significant number of them, going about their lives normally, eventually get naturally infected. This can take years.
To speed that up, some epidemiologists and scientists are calling for something called a human challenge trial, in which a subject who has been given the vaccine is deliberately infected. This isn’t a new concept; human challenge trials have been used to develop vaccines or treatments for lots of diseases, like cholera, typhoid, malaria, influenza, and common cold viruses. But what sets Covid-19 apart from those diseases is that it currently has no effective treatment. Because it’s so new, we also aren’t fully aware of its long-term health effects. Unlike other human challenge trials, a Covid-19 challenge trial would entail a risk of serious illness — and even death.
It’s because of those risks that a Covid-19 challenge trial would be limited to the young and healthy, who would be at the lowest risk of harm. But there are questions beyond the ethics. Would artificially infecting someone in a lab setting provide useful information on how to prevent natural infection? Would a study performed on only young and healthy people produce a vaccine that works for everyone? And with some vaccines already far along in their phase III trials, would a human challenge trial do any good at this point?
Even though no Covid-19 human challenge trials are currently planned, more than 30,000 people from nearly 150 countries have already said they would volunteer for one if the opportunity presented itself. The question is, should we let them?
Note: The headline on this piece has been updated.
Previous headline: Would you volunteer to get Covid-19?
Further reading:
1DaySooner is the grassroots organization recruiting volunteers for the possibility of a human challenge trial:
https://1daysooner.org/
For more of Vox’s coverage on human challenge studies:
https://www.vox.com/future-perfect/2020/5/20/21258725/covid-19-human-challenge-trials-vaccine-update-sars-cov-2
For more on the ethical and acceptance concerns with vaccine development:
https://medium.com/oxford-university/challenging-circumstances-we-need-international-guidelines-for-human-infection-studies-688051c869f9
For a history of challenge studies for other diseases:
https://www.sciencemag.org/news/2016/05/studies-intentionally-infect-people-disease-causing-bugs-are-rise
For coverage of the typhoid vaccine we mention in the video:
https://www.nytimes.com/2017/09/28/health/typhoid-vaccine-trial.html
For coverage of Oxford University’s statement on human challenge trials:
https://www.theguardian.com/science/2020/jul/16/coronavirus-vaccine-oxford-team-volunteers-lab-controlled-human-challenge-trial
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