The number of new coronavirus cases continues to rise, prompting researchers and pharmaceutical companies to develop drugs and vaccines to treat and prevent COVID-19.

Many researchers are even reaching into the existing list of medications for repurposing.

Human trials for coronavirus treatments and vaccines have been taking place in China to ensure the safety and efficacy of the new and existing treatments.

Some people receive the drugs but others are given a placebo during clinical trials to determine the safety and efficacy, which is why most people are now hesitating to sign up for clinical trials, knowing that there is a 50 percent chance of being assigned to placebo groups.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Disease (NIAID), said he weighs on treatments using existing drugs through repurposing.

He gave an example of the chloroquine, anti-malarial drug, as a potential coronavirus treatment through drug repurposing.

“I think so much is out there on social media and in medical letters and reports that are not reviewed that people are going to start using it anyhow,” said Dr. Fauci. “Hopefully a program will make it accessible at the same time that it is being studied.”

Some researchers said that ACE inhibitors, such as losartan, which are prescribed to treat high blood pressure, could be used to treat coronavirus. They said these antihypertensive agents block receptors on lung cells similar to the receptors where SARS-CoV-2 (COVID-19) binds and enters. However, there is no enough evidence.

Antivirals such as Kaletra (lopinavir/ritonavir) and remdesivir have been undergoing clinical trials to treat COVID-19. However, Kaletra, which is an HIV drug, has failed to show any benefits in treating COVID-19. On the other, the results of remdesivir, an Ebola drug, are still waiting, although it has shown some promise in treating the virus.

Corticosteroids (especially methylprednisolone) have been undergoing clinical trials to treat COVID-19 pneumonia. Another clinical trial is comparing a combination of four drugs.

Some researchers are even studying the effects of Viagra (sildenafil) on 10 coronavirus patients who are at risk of remission or progression. Sildenafil, a drug prescribed to treat erectile dysfunction and pulmonary hypertension, has the ability to dilate blood vessels, which could help fight lung inflammation caused by the virus.

Another drug called thalidomide is also undergoing trials, which is an anti-inflammatory drug. Researchers say thalidomide could help control lung inflammation and halt lung damage caused by the coronavirus.