Taking it together with a low dose of ritonavir helps slow the breakdown of PF-07321332. It therefore remains active in the body for a longer period at a high concentration, to help combat the virus. The pill could potentially help patients avoid severe illness, which can lead to hospitalisation and death, Pfizer said. "We believe oral antiviral treatments can play a vital role in reducing the severity of Covid-19 infections, decreasing the strain on our healthcare systems and saving lives," said Pfizer chairman and chief executive Albert Bourla. While a multitude of vaccines have been rolled out in the pandemic, the hunt for treatments for those who have already caught the disease has not been as fruitful. Agreement follows Merck deal The MPP was founded by Unitaid, which works on innovations to prevent, diagnose and treat major diseases in poorer countries. "During a pandemic, saving time means saving lives.