NEW YORK -- COVAX, the global COVID-19 vaccine equity scheme, has agreed to buy 110 million Chinese doses of Sinovac and Sinopharm, thus gaining immediate access to lifesaving vaccines that are proved to be safe and effective, a vaccine expert has said.

Such a decision by COVAX offers "some advantages in low-resource settings when most global manufacturers are unable to supply COVAX with the volumes it needs," said Seth Berkley, chief executive of Gavi, or The Vaccine Alliance, a public-private global health partnership with the goal of increasing access to immunization in poor countries.

"More than 50 percent of U.S. citizens have been fully vaccinated, but only 1 to 2 percent of people in lower-income countries have received their first dose," said Berkley in an Opinion article published by The Washington Post on Sunday.

"To stop the virus from circulating and continuing to mutate, we urgently need to address this vaccine divide," said the expert.