Underscoring the level of concern in the industry, AstraZeneca's chief executive Pascal Soriot said his researchers were even contemplating running so-called "challenge" trials - where participants would be given the experimental vaccine and then deliberately infected with COVID-19 to see if it worked. Such trials are rare, high risk and hard to get ethical approval for.
As a more practical and swifter option, Soriot and others are looking to Brazil and other countries in South America, as well as parts of Africa where COVID-19 outbreaks are still growing and peaking, as ripe drug and vaccine testing grounds.
Difficulty recruiting candidates for mid-stage vaccine trials in countries where the COVID-19 pandemic is on the wane may be foreshadowed by the experience of doctors seeking infected cases for the World Health Organization's multi-country Solidarity trial of potential treatments for the disease - including the generic drug hydroxychloroquine and Gilead's remdesivir.
In the Swiss portion of that trial, for instance, it took three weeks to get all of the ethical and regulatory approvals from authorities, and another week to get all the drugs, said Oriol Manuel, an infectious disease expert and national coordinator of the Solidarity study in Switzerland.
"We were able to enroll some patients in (one trial centre in) Lausanne," Manuel said. "But when all centres were ready, the cases were fortunately disappearing."
