Cuba’s ambitions may be challenged when researchers are ready to launch late-stage trials. Vaccines are more easily tested in places with rampant virus spread, but Cuba’s transmission rate is very low, with just about 500 confirmed active cases.

Also mentions the "state-run media". Thank god for Free American Media™ amirite?

https://www.reuters.com/article/health-coronavirus-vaccine-cuba/focus-cuba-leads-race-for-latin-american-coronavirus-vaccine-idINL8N2HV6FK