As pressure for coronavirus vaccine mounts, scientists debate risks of accelerated testing
CHICAGO: Drugmakers are working as quickly as possible to develop a vaccine to combat the rapidly spreading coronavirus that has infected more than 100,000 people worldwide.
Behind the scenes, scientists and medical experts are concerned that rushing a vaccine could end up worsening the infection in some patients rather than preventing it.
Studies have suggested that coronavirus vaccines carry the risk of what is known as vaccine enhancement, where instead of protecting against infection, the vaccine can actually make the disease worse when a vaccinated person is infected with the virus. The mechanism that causes that risk is not fully understood and is one of the stumbling blocks that has prevented the successful development of a coronavirus vaccine.
Normally, researchers would take months to test for the possibility of vaccine enhancement in animals. Given the urgency to stem the spread of the new coronavirus, some drugmakers are moving straight into small-scale human tests, without waiting for the completion of such animal tests.
“I understand the importance of accelerating timelines for vaccines in general, but from everything I know, this is not the vaccine to be doing it with,” Dr Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, told Reuters.
Hotez worked on development of a vaccine for SARS (Severe Acute Respiratory Syndrome), the coronavirus behind a major 2003 outbreak, and found that some vaccinated animals developed more severe disease compared with unvaccinated animals when they were exposed to the virus.
“There is a risk of immune enhancement,” said Hotez. “The way you reduce that risk is first you show it does not occur in laboratory animals.”
Hotez testified last week before the U.S. House Committee on Science, Space and Technology about the need for sustained funding for vaccine research. There remains no vaccine for any of the new coronaviruses that have caused outbreaks in the past 20 years.
At least for now, the world’s experts have concluded that accelerated testing is a risk worth taking.
At a specially convened World Health Organization (WHO) meeting in mid-February, designed to co-ordinate a global response to the new coronavirus, scientists representing government-funded research organizations and drugmakers around the world agreed that the threat was so great that vaccine developers should move quickly into human trials, before animal testing is completed, four people who attended the meeting told Reuters.
“You want to have a vaccine as quickly as possible,” Dr Marie-Paule Kieny, former assistant director-general at the WHO, who co-chaired the meeting, told Reuters. “You have to balance this with the risk that you impose on a very small number of people, and do all you can do to mitigate this risk as much as possible.” – Reuters