A staff member tests samples of the inactivated virus vaccine at a production plant of the China National Pharmaceutical Group in Beijing, on April 11.
CNN  — 

The United Arab Emirates (UAE) and China have launched a Phase 3 clinical trial of a coronavirus vaccine, according to the China National Biotec Group (CNBG) and UAE state media.

The launch is another development in the race to find a scientific solution to the pandemic.

The trial agreement, announced Wednesday, was signed by UAE-based artificial intelligence and cloud computing company G42 and the Sinopharm Group, a Chinese pharmaceutical company and affiliate of CNBG.

Drugmakers globally are working to find a coronavirus vaccine. It’s unclear if or when a vaccine will be available to the public as of yet, but researchers hope to produce one by early 2021.

Vaccines have to go through multi-phase trials to ensure they’re effective and safe, and typically take years to develop.

Clinical development typically takes three phases according to the US Centers for Disease Control and Prevention . Small groups of people receive the trial vaccine in Phase 1. In Phase 2, the group receiving the vaccine expands, to include people who have characteristics similar to those for whom the new vaccine is intended.

A Phase 3 trial can be a pivotal moment. It is typically used to test the effectiveness of a vaccine in humans. It can also be used to confirm results from Phase 1 and 2 vaccine trials in a larger sample size.

Thousands or tens of thousands of people often participate in Phase 3 trials. The substantially larger number of participants at this stage helps scientists learn about possible rare side effects from the vaccine.

“If a vaccine is confirmed safe and effective throughout the entire clinical trial process, the test is considered successful, and the vaccine enters into the large-scale manufacturing phase,” UAE state news agency WAM reported.

Coronavirus vaccines in development around the world are in various stages of testing. There are 16 candidate vaccines in clinical evaluation and a further 125 in preclinical evaluation according to the World Health Organization.

The UAE and China collaboration is not the only vaccine at the Phase 3 stage. The University of Oxford has started a Phase 3 trial on its vaccine candidate and the US company Moderna plans to start its Phase 3 trial of 30,000 participants in July.

Many trials face an obstacle, as virus levels begin to decline. The point of Phase 3 is to vaccinate people and then see if they naturally become infected, but with lower rates of circulating virus, the study subjects are less likely to be exposed to the virus in the first place.

And while scientists remain optimistic about the eventual development of a vaccine, there’s no guarantee that one will be found.

Jacqueline Howard contributed to this report from Atlanta.