A significant number of people who suffered from chronic heartburn and were taking an over-the-counter acid suppressant were able to survive COVID-19, a study has found.

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The low-cost drug called famotidine, with the key ingredient Pepcid, was developed to block the histamine receptors that help produce acid in the stomach. A team from the University of Virginia examined 22,000 people, the largest sample size for a study on famotidine and the disease to date. The team's analysis, which appeared in the journal Signal Transduction & Targeted Therapy, showed that the data supported findings from other smaller-scale studies. When delivered at high doses (the equivalent of about 10 Pepcid tablets), famotidine appears to improve the odds of survival for COVID-19 patients, especially when it is combined with aspirin.

It also seems to hinder the severity of disease progression, making patients less likely to reach the point where they require intubation or a ventilator. One of the most dangerous phenomena of COVID-19 is that it can trigger a cytokine storm -- a potentially fatal amplification of an immune response. Once infected, the immune system releases inflammatory proteins called cytokines that tell the immune cells how to fight the infection. But in more severe illnesses, cytokine production can spiral out of control, becoming dysregulated.

"Basically, your immune system goes haywire and starts attacking things like your otherwise healthy lung tissue because it's so desperate to kill off the invading virus," said Cameron Mura, senior scientist at UVA. The researchers note that famotidine suppresses this reaction. But, like all other medications, it can cause side effects -- interfering with cytokine storms. "It may well be a case of famotidine having a beneficial off-target effect," Mura said.

But other studies have offered conflicting pictures of what famotidine can do for COVID-19 patients: Some have found that it has a neutral effect and one has even suggested that it might be detrimental. However, the team suggested combining famotidine with aspirin. The study has shed further light on an inexpensive and safe potential treatment that would be easy for doctors to prescribe.