US pharma company raises vaccine hopes but more trials are vital, say experts

Hopeful news about a Covid-19 vaccine developed by US government researchers and Moderna Inc has buoyed expectations – and markets – on the potential for a preventive measure against a global pandemic that has killed more than half a million people and upended daily life.

Moderna first announced its vaccine, backed by the National Institute of Allergy and Infectious Diseases, prompted an immune response in 45 adults in May.

On Tuesday, it published a fuller look at the data in a report in the New England Journal of Medicine.

But experts cautioned against heightened expectations about the Moderna vaccine, one of many being worked on around the world, as it is still in the early stages of development.

The report was “certainly no cause for celebration”, said Dr Peter Hotez, dean for the National School of Tropical Medicine at Baylor College, and a vaccine researcher in Houston, Texas. “But [it is] provocative enough that it’s worth looking at in a phase 3 trial.”

“These are small studies,” Hotez added. “This is why you have to do the big phase 3 clinical trials in 10,000 to 30,000 patients,” he said.