When looking at major developments in the race to find a vaccine for the deadly virus, Dexamethasone proves to be the first life-saving drug.
So far there have been dozens of drugs tested, more than 100 vaccine candidates, and hundreds of clinical trials under way.
Following is a rundown of the major developments in the search for Covid-19 treatments and prevention:
Dexamethasone: Saves lives
Cheap and widely available, dexamethasone is a steroid normally used to treat allergic reactions as well as rheumatoid arthritis and asthma.
This week, a team of researchers looking for Covid-19 treatments said that dexamethasone had reduced deaths among the most seriously ill patients by a third compared to regular treatment.
The British government immediately said patients would start receiving the first medicine proven to reduce Covid-19 mortality.
However, while researchers believe dexamethasone could save the lives of one-in-eight patients on ventilators, it was shown to have little clinical benefit among less serious cases.
Remdesivir: Marginal gains
At least two major US studies have shown the antiviral drug remdesivir can reduce the duration of hospital stays for Covid-19 patients.
Research published in the leading journal the New England Journal of Medicine in May showed that injections of remdesivir, which was originally intended as treatment against Ebola, accelerated patient recovery compared with a placebo.
Washington authorised the emergency use of the medicine on May 1, followed by several Asian nations including Japan and South Korea.
While notable, the drug’s effects do not appear to be miraculous: on average it reduced patients’ hospital stays from 15 days to 11.
One study published in The Lancet, however, found no “significant clinical benefit” from treating coronavirus patients with remdesivir.
Hydroxychloroquine: Mixed results
Vaunted by US President Donald Trump as a miracle guard against Covid-19, there is little scientific evidence that the decades-old malaria drug actually works as a treatment.
This month, the British research group RECOVERY concluded that the medicine did not help Covid-19 patients at all.
A study in The Lancet, retracted due to problems with the data, claimed that hydroxychloroquine also showed no benefit and even increased the risk of death, prompting several trials to be paused.
On Monday the US withdrew its authorisation for emergency Covid-19 treatment with hydroxychloroquine and a similar medicine, chloroquine.
On Wednesday the World Health Organisation announced that hydroxychloroquine can be ruled out as treatment for hospitalised patients.
It did, however, recognise trials under way may show that the drugs have some value as a preventative measure.
Several other medicines intended for other maladies have been trialed against Covid-19.
According to The Lancet there have already been more than 1,000 clinical trials on dozens of pharmaceutical treatments. Among the most promising are antiretrovirals lopinavir and ritonavir, the antipsychotic chlorpromazine and tocilizumab, an immunosuppressor.
Trials involving transfusing plasma from recovered patients have also shown some potential. But despite the unprecedented research effort there is still no totally effective medical intervention against Covid-19.
Most experts think that rather than stumbling upon a miracle drug that kills the virus, treatment programmes will likely rely on a variety of medicines administered together.
How many in the pipeline?
In its most recent update on June 16, the WHO identified 11 separate clinical trials under way around the world for a Covid-19 vaccine.
More than half of the trials involving humans (as opposed to lab animals) are in China, where the deadly SARS-CoV-2 virus that causes Covid first emerged. Even as new cases surge in Beijing, China wants to be the first country in the world to come up with a vaccine and has fast-tracked its trials.
Worldwide, the vaccine candidates under development are mostly in Phase 1 trials, the first of three steps that is designed to test safety. A few are in Phase 2 which, along with Phase 3, tests for efficacy.
Among the most advanced is a European project led by the University of Oxford in cooperation with pharmaceutical company AstraZeneca. Another in China, involving the Academy of Military Medical Sciences and the firm CanSinoBIO, is also well under way.
Besides vaccine trials already in the pipeline, the WHO has listed another 128 candidate vaccines that are still at the pre-clinical phase. Another attempt to catalogue all ongoing vaccine developments undertaken by the London School of Hygiene and Tropical Medicine counts at least 194, including 17 in the trials phase.