By Julia Hollingsworth, Saruul Enkhbold and Amy Sood, CNN In Mongolia, hospitals are overwhelmed. In the tiny archipelago of Seychelles, more than 100 new Covid-19 cases are being reported each day. And in Chile, a nationwide lockdown was lifted this week — but the country is still reporting thousands of daily cases. What links these countries is that they have each fully inoculated more than 50% of their populations, largely with Chinese-made coronavirus vaccines. And that’s raised questions over the vaccines’ efficacy. If the Chinese vaccines aren’t working, that’s a huge problem — and not just from a health perspective. Beijing has staked its reputation on providing other countries with vaccines.