NEW YORK: US biotech group Novavax Inc has joined the race to test coronavirus vaccine candidates on humans and enrolled its first participants on Monday.

Novavax, shares in which surge about 23% to $56.50 in premarket trade, said it expects preliminary readings on safety and on indicators of an immune response from the trial in July.

The announcement comes as drugmakers pause clinical trials on drugs for other ailments to focus on COVID-19, the illness caused by the novel coronavirus that has infected more than 5.3 million people worldwide and resulted in more than 343,000 deaths.

The World Health Organization (WHO) on Friday said that 10 experimental vaccines were being tested on humans, including the Novavax compound.

Groups including CanSino, Moderna and an alliance between Oxford university and AstraZeneca have moved or are close to moving on to enlarged trials from initial testing on small groups of participants.

Novavax last month said it had identified a candidate, NVX-CoV2373, with which it planned to use its Matrix-M adjuvant to enhance immune responses.

Adjuvants are designed to boost the immune response induced by a vaccine and provide longer-lasting protection against infections.

Novavax said that the Phase 1 trial in Australia would involve about 130 healthy participants aged 18 to 59, with a second phase to be conducted later in several countries, including the United States.

The Phase 2 trial will assess immunity, safety and COVID-19 disease reduction in a broader age range, Novavax said.