Hospitals in New York have been quietly testing a heartburn drug as a treatment for coronavirus after doctors in China found that elderly survivors were taking it.

Northwell Health had tested famotidine, sold in oral form under brand name Pepcid in the US and the UK, on 1,1174 patients - including 187 who were critically ill - as of Saturday as part of an American trial.

Interim results from 391 patients should be available in 'a few weeks' Kevin Tracey, a former neurosurgeon in charge of Northwell's research told Science magazine.

Interest in the drug amid the pandemic developed after doctors in Wuhan found that although one in five COVID-19 patients over the age of 80 were dying, of the survivors, many were taking pills for heartburn.

Northwell Health had tested famotidine (sold in oral form under brand name Pepcid) on 187 critically ill patients out of an intended 1,174 as of Saturday as part of an American trial. Pictured in this file image, is Lenox Health Medical Pavilion part of Northwell Health system in New York on March 28

Doctors in Wuhan found that some elderly patients in China who were on famotidine (pictured) were surviving coronavirus

They discovered that the poor elderly people had a higher survival rate. The poor patients used famotidine because it was cheaper than omeprazole. Famotidine is sold under the brand name Pepcid and omeprazole is sold as Prilosec.

In a review of 6,212 medical records, with many patients on ventilators, the doctors in China found that only 14 percent of the elderly people using famotidine died while 27 percent of elderly people on omeprazole passed away.

Scientists suspect that in COVID-19, famotidine binds to the papainlike protease, an enzyme which helps viruses replicate in the body and stops them replicating.

US scientists have used the 3D structures of 2003's SARS coronavirus to predict the behavior of the new coronavirus, COVID-19.

WHAT IS FAMOTIDINE? Famotidine is an antacid and antihistamine which blocks certain receptors that trigger the release of stomach acid. It’s known as an H2 (histamine 2) blocker and is sold under the brand name Pecid or Pepcid AC. As well as treating heartburn caused by acid indigestion, it is also used to treat stomach ulcers and gastroesophageal reflux disease. Advertisement

Testing 2,600 compounds on the new protease, they found several dozen that proved promising in how they interacted with the protease but pharmacists have narrowed it down to three, one of which is famotidine.

After getting approval from the FDA, Northwell – which runs 13 hospitals in New York – used its own money to start a blind double trial.

On April 14, the US Biomedical Advanced Research and Development Authority (BARDA), which operates under Kadlec, gave Florida-based Alchem Laboratories, a $20.7 million contract for the trial. The money is reported to cover most of Northwell's upfront cost.

Doctors have only been able to gather enough patients to test on because many are undergoing trials of anti-malarial drug hydroxychloroquine. A group of patients on hydroxychloroquine and famotidine will be compared to those on just hydroxychloroquine as well as hundreds treated early on in the COVID-19 outbreak.

'Is it good science? No,' Northwell's Tracey told Science magazine. 'It's the real world.'

David Tuveson, director of the Cold Spring Harbor Laboratory Cancer Center, recommended famotidine to his sister, who had coronavirus.

The 44-year-old New York City hospitals engineer's lips wee blue with hypoxia but after taking her first megadose of famotidine her fever broke the following day and her oxygen saturation level returned to normal.

Tuveson said five of her colleagues who had the new virus also recovered after taking over-the-counter versions of famotidine.

Those over 80 with heartburn issues and that used the cheaper drug, Pepcid (left), had a higher survival rate than those using the expensive alternative, Prilosec (right). Pepcid contains famotidine and Prilosec contains omeprazole

Scientists suspect that in COVID-19, famotidine binds to the papainlike protease which helps pathogens replicate in the body and stops them replicating

Michael Callahan, a doctor based at Massachusetts General Hospital in Boston, returned from Wuhan with the famotidine information and now it is being used with hydroxychloroquine

They kept trials under wraps as after President Trump called the anti-malarial drug a 'gamechanger' in a coronavirus task force briefing, people have rushed to hoard it.

'If we talked about this to the wrong people or too soon, the drug supply would be gone,' Tracey said.

Timothy Wang, head of gastroenterology at Columbia University Medical Center, is also helping Northwell's efforts by retrospectively reviewing records of 1,620 COVID-19 patients.

Northwell is also testing Regeneron's sarilumab and Gilead Science's remdesivir.

There's not enough evidence to suggest any drug as an effective COVID-19 treatment.

Michael Callahan – a doctor based at Massachusetts General Hospital in Boston who returned from Wuhan with the famotidine information – has since evacuated Americans off two cruise ships with coronavirus outbreaks.

He said: 'No amount of smart people at the [National Institutes of Health] or Harvard or Stanford can outclass an average doctor in Wuhan.'