Moderna slows Covid-19 vaccine trial enrollment

Moderna is slowing the enrollment of volunteers in its phase three clinical trial for its Covid-19 vaccine candidate in order to ensure that minorities, who are among the most at risk population groups, are adequately represented.

As of 28 August, the biotechnology outfit had enrolled 17,458 volunteers out of the total of 30,000 that were needed, with roughly a quarter of those coming from minorities.

Moderna chief executive officer, Stephane Bancel, whose company is one of the front-runners in efforts to find a successful vaccine said that diversity mattered more than speed.

"I would rather we have higher diverse participants and take one extra week," he said.

Shares of Moderna were falling by 6.4% to $60.72 as of 1609 BST on the back of the announcement, but were still sporting a year-to-date gain of roughly 200%.

According to experts, efficacy data for minorities, the elderly and those with previous conditions - all of whom were at more risk of suffering severe Covid-19 - were all key.

Bancel also said that the company's aim was to replicate the proportion of each ethnic group in the volunteer group as per the last US census.

To take note of, as of 27 August, rival Pfizer had enrolled 23,000 of the projected 30,000 participants for a phase three clinical trial for its own vaccine candidate.

The day before, Pfizer chief, Albert Bourla, had said that a read-out on the results of its phase three trial should be ready "by the end of October".

Stock in Pfizer was down 1.06% to $36.02, while those of BioNTech, with whom it was developing the vaccine were dropping 5.36% to $56.1.