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Vaccine trials ‘can’t detect’ virus risk reduction: expert
Patrick Galey (Agence France-Presse) – October 22, 2020 – 8:17 am
PARIS – None of the COVID-19 candidate vaccine trials can detect a reduction in serious outcomes such as hospitalization or death, a leading public health expert said Thursday.
In an article in the medical journal BMJ, Associate Editor Peter Doshi cautioned that not even ongoing Phase 3 trials in the race for a vaccine can demonstrate that their product will prevent people from contracting COVID-19.
In a sobering trial, Doshi said that those hoping for a breakthrough to end the pandemic will be disappointed, as some vaccines will likely reduce the risk of COVID-19 infection by just 30%.
“None of the currently ongoing trials are designed to detect a reduction in any serious outcomes, such as hospital admissions, use of intensive care or deaths,” he wrote.
“Nor are vaccines being studied to determine if they can interrupt transmission of the virus.”
The World Health Organization (WHO) has identified 42 candidate vaccines in clinical trials, ten of which are in the most advanced stage of “Phase 3”.
This is where the efficacy of a vaccine is tested on a large scale, usually tens of thousands of people on various continents.
But Doshi, an assistant professor of pharmaceutical health services research at the University of Maryland School of Pharmacy, said that even the most advanced trials evaluate mild rather than severe disease.
This may be due to the number of people involved in the trials, he said, noting that the majority of confirmed COVID-19 infections involve little or no symptoms.
And few, if any, of the current trials are designed to find out whether there is a benefit among the elderly, a key group at risk.
Without enrolling frail and elderly volunteers in the trials in sufficient numbers, Doshi said “there may be little basis for assuming any benefit against hospitalization or mortality.
He added that children, immunosuppressed people, and pregnant women had been largely excluded from the trials, so the experiments are unlikely to address key gaps in our understanding of how Covid-19 develops differently between women. people.
Thirty percent risk reduction
Several trials have already stopped after participants got sick.
Many countries plan to prioritize vulnerable people once a vaccine is available, but Doshi said those hoping for a miraculous end to the pandemic would have to wait.
He said several pharmaceutical firms had designed their studies “to detect a relative risk reduction of at least 30% in participants who develop laboratory-confirmed COVID-19.”
Recent studies have also confirmed that it is possible for someone to be reinfected with COVID-19, a development that can affect the way governments shape their vaccination plans.
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