We keep hearing claims that this or that drug will be a game changer in the coronavirus pandemic. So what would a treatment have to do to be a game changer?
First, it needs to work. Most of the reported results from experiments that have been hurriedly set up in response to the covid-19 outbreak are either not from rigorous randomised controlled trials, or involve such small numbers that the results are far from conclusive. 鈥淣o therapies have been shown [to be] effective to date,鈥� concludes .
It seems likely that at least a few of the many treatments being trialled will prove effective, but that doesn鈥檛 mean they will make a huge difference to the course of the pandemic. Doctors describe drugs as effective if they have an effect, but often the effect is small. A drug that reduces the number of seriously ill people dying by, say, 20 per cent would save many thousands, but it wouldn鈥檛 mean we could all resume normal lives.
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There is no formal definition of a 鈥済ame changer鈥�, but to me it would be something that transforms the wider situation. It might be, say, a drug that dramatically reduces the proportion of people admitted to hospital with covid-19 becoming so ill they require ventilation, greatly easing the burden on healthcare systems.
Better yet would be a drug that stops almost all those infected becoming seriously ill in the first place.
The criteria for such a treatment are very different to one given at a later stage, says Trudie Lang at the University of Oxford. An early treatment will have to be in pill form so people can take it at home, be very cheap so it can be dished out to millions, and be extremely safe because most people who take it would probably be fine without it, because they may never contract covid-19 or have anything more than mild symptoms if they do.
By contrast, treatments given to people who have become seriously ill can include drugs that need to be injected 鈥� such as antibodies 鈥� and may be more expensive, because they will be given to fewer people. A risk of serious side effects won鈥檛 be a showstopper as long as the benefits are greater.
Late-stage treatments are likely to work by calming the over-reaction of the immune system 鈥� the cytokine storm 鈥� that kills most people. Early stage treatments are likely to target the virus. The catch here is that antiviral drugs are more effective when taken early, but in most countries people infected with the coronavirus are only being identified late on, after being taken to hospital, say.
鈥淚f it only works in the first three days after infection, it would be basically be useless,鈥� says Christopher Coleman at the University of Nottingham in the UK.
If a drug were cheap and safe, though, it could be given to anyone who might have been exposed, without any testing. 鈥淭he dream scenario is a really safe drug that you can give to the whole population,鈥� says Lang.
In fact, such a drug could even be used to prevent infections. If we could all protect ourselves by popping a pill,聽say, once a week, we could end the lockdowns.
Unfortunately, there are no clear contenders for this type of drug. For instance, the safety factor rules out chloroquine and hydroxychloroquine, touted as game changers by Donald Trump. It still isn鈥檛 clear if either works, and at least because of people developing serious heart and eye problems.
鈥淲hether or not they will come up with a game-changing drug, I鈥檓 not sure,鈥� says Lang.
And it gets worse 鈥� even if we do find a game-changing antiviral, the virus could quickly evolve resistance and render the drug useless.
For now, we cannot assume that a transformative treatment will be found. 鈥淚 believe the game changer here is not getting the miracle drug but focusing on preventive measures such as social distancing and a lot of testing,鈥� says Gaetan Burgio at the Australian National University. 鈥淲e clearly see the difference [that is making] in Australia, Germany or Korea versus the UK, France or the US.鈥�
