A man receives a shot of China-aided vaccine in Conakry, capital of Guinea, March 5, 2021. (Xinhua)

"If the weakest link is in some faraway country wherever the COVID-19 is still ... prevalent, we will all have ... mutations of COVID-19 which will defeat the vaccines already exist," said a renowned U.S. expert.

WASHINGTON, March 11 (Xinhua) -- China's pledge and action to make its COVID-19 vaccine a global public good will help strengthen "the weakest link" in the world's battle against the pandemic, a renowned U.S. expert has said.

"I think China's doing about it the right way," Sourabh Gupta, a senior fellow at the Washington-based Institute for China-America Studies, told Xinhua recently, when talking about China's dispatching vaccines to countries in dire need.

"If the weakest link is in some faraway country wherever the COVID-19 is still ... prevalent, we will all have ... mutations of COVID-19 which will defeat the vaccines already exist," he said.

As vaccine researchers are working around the clock to offer stronger and broader protection against COVID-19, preliminary data from a study in Brazil indicates that a type of vaccine developed by China's Sinovac Biotech is effective against the P1 variant first detected in Brazil, Sao Paulo State Governor Joao Doria confirmed to Reuters on Wednesday.