BRUSSELS (REUTERS) - US drugmaker Merck & Co Inc has begun recruiting participants to its early-stage Covid-19 vaccine study, according to the government database clinicaltrials.gov.

The phase 1/2 trial, which is based in Belgium, aims to recruit 260 healthy participants to test the experimental vaccine V591, which it gained access to as part of its May deal for Austrian vaccine maker Themis Bioscience.

The vaccine is based on a modified measles virus that delivers bits of the new coronavirus into the body to prevent Covid-19.

Merck is late to join the race to develop a safe and effective vaccine for the fast-spreading respiratory illness as rivals Pfizer Inc, AstraZeneca Plc and Moderna Inc are already in late-stage testing.

The drugmaker is also collaborating with research non-profit IAVI on a second vaccine candidate that uses the same technology as Merck's Ebola vaccine, ERVEBO.

Earlier this month, Chief Executive Kenneth Frazier had said the second candidate is likely to begin trials later this year.

The Wall Street Journal first reported the news on Friday.