Favipiravir, an antiviral drug used to treat influenza in Japan has been found to be effective in treating COVID-19. Zhang Xinmin, a spokesperson of China’s science and technology ministry said they had found promising results from the use of Favipiravir or Avigan in 340 coronavirus patients. Zhang said the antiviral drugs proved to be effective and highly safe in the clinical trial conducted in Wuhan and Shenzhen.
The antiviral drug synthesized by a Japanese pharmaceutical company, Fujifilm Toyama Chemical was being mass-produced in Zhejiang Hisun Pharmaceutical as a treatment for influenza virus infections. In February, Favipiravir was approved for a clinical trial in COVID-19 patients.
The clinical trial involved COVID-19 positive patients from Shenzhen. These patients received the antiviral drug test and tested negatively for the COVID-19 just four days after starting the drug. Half of the patients had negative virus test results even earlier than four days after starting the drug. Whereas patients who were not placed on the antiviral drug tested negative after 11 days on average.
91 % of patients on Favipiravir showed resolution of lung consolidation on X-ray while only 62 % of non-treated patients had improvements in lung conditions. Additionally, the clinical trial in Wuhan reported a shorter febrile period from 4.2 days to 2.5 days.
Favipiravir was designed specifically to treat RNA viruses like Influenza and SARS-CoV-2, both are viruses whose genetic material is RNA instead of DNA. The mechanism of the drug is to inhibit RNA polymerase, the enzyme that builds RNA. When RNA polymerase becomes damaged or non-functional, the virus cannot replicate efficiently inside the host cell.
However, the drug is effective only when the patients are in the early stages or in their milder form. In patients who had already developed pneumonia, the virus had already replicated to a significant amount. Hence, stopping further replication by using Favipiravir had little value, as the virus had already replicated to numbers high enough to cause serious complications.
“We’ve given Avigan to 70 to 80 people, but it doesn’t seem to work that well when the virus has already multiplied,” stated a spokesperson from the Japanese Health Ministry.
In Japan, patients without serious complications are already being treated with Avigan to prevent the development of complications. Results from the trials in Wuhan and Shenzhen have not been verified, hence it has not yet been published in a peer-reviewed scientific journal.
As of now, no drug has been officially approved for treating COVID-19 but researchers are already testing antiviral drugs developed by pharmaceutical companies.
A clinical trial in Seattle for the coronavirus vaccine has officially started but is still in its early experimental phase. The trial involving 45 participants will be testing the safety and efficacy of the vaccine to initiate an immune response. However, it will take at least 12 to 18 months for the vaccine to be ready for public use.