Supporters of human challenge trials say they are a good way to cut short the often lengthy process of testing potential vaccines on tens of thousands of volunteers in the real world who go about normal life and are monitored to see if they contract the disease or are protected from it.
In these tightly-controlled trials, volunteers are given a vaccine and then about a month later are deliberately infected with the disease under controlled conditions. They are then isolated in a quarantine facility and monitored to see if they become sick or if the vaccine protects them.
European countries are facing shortages of Covid-19 drug remdesivir because limited supplies are running out, with cases surging and the US having bought up most of drugmaker Gilead’s output.
Vaccines normally require years of testing and additional time to produce at scale, but scientists are hoping to develop a coronavirus vaccine within 12 to 18 months.Vaccines mimic the virus – or part of the virus – they protect against, stimulating the immune system to develop antibodies. They must follow higher safety standards than other drugs because they are given to millions of healthy people.