Look at data on COVID-19 vaccines with caution, experts warn


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Despite the optimism generated by the release of preliminary results from clinical trials of the COVID-19 vaccine, experts are warning much work remains to be done before a possible vaccination campaign.

“One would think that at this stage of the pandemic, we would be more suspicious and skeptical of scientific announcements made in press releases,” said Ross Upshur of the University of Toronto’s Dalla Lana School of Public Health.

“The data that has been released was preliminary data,” added Alyson Kelvin of Dalhousie University. “The trials are still ongoing.”

Two manufacturers, Pfizer and Moderna, recently announced their vaccines are 95-per-cent effective. These announcements have boosted stock markets and prompted politicians to call for rapid, widespread distribution, bringing a sense of optimism.

But we should wait a moment before rejoicing, experts say.

A 95-per-cent effective vaccine doesn’t mean it completely protects 95 per cent of recipients. It means recipients have a 95-per-cent lower chance of contracting the disease than someone who didn’t receive it.