MEXICO CITY, Dec 29 (Reuters) - Mexico earlier this year slashed its COVID-19 vaccine order with CanSino Biologics by more than half when it became clear that the Chinese company would deliver far less than agreed, three people familiar with the matter said Wednesday. Mexico informed CanSino (6185.HK)in July it would reduce its order to roughly 14.5 million doses from 35 million as it sought to ramp up supplies from other sources, according to a Mexican official with knowledge of discussions. The first batch of CanSino vaccines reached Mexico in March, and nearly all the 14.1 million doses the country has since received were bottled in the central Mexican state of Queretaro. A Mexican health ministry source said Mexico modified its agreement when it became clear CanSino would fall well short of delivering 35 million doses by September as had been agreed. The contract would not be renewed, the source added. A spokesperson for Mexico"s health ministry did not respond to a request for comment. A representative for CanSino did not immediately reply to a request for comment. The contractual shake-up was initially reported by Mexican newspaper La Jornada. Mexico"s initial vaccine rollout was hampered by shortfalls in supply from pharmaceutical companies, and the government vigorously lobbied for wealthy countries to make vaccines more easily accessible to less well-off parts of the world. The United States in due course agreed to send more vaccines to Mexico, which has now acquired around 200 million doses.