Chinese pharmaceutical companies including Sinopharm and Sinovac signed agreements to supply millions of doses of COVID-19 vaccines with international NGOs on behalf of the COVAX facility on Monday.

Sinopharm has signed a longer-term agreement with UNICEF to provide up to 120 million doses of its vaccine by the end of 2021 for participating countries and territories in the COVAX program, as well as self-financing participants.

It is the seventh supply agreement UNICEF has signed for COVID-19 vaccines after agreements with other vaccine suppliers including Pfizer, AstraZeneca, Moderna and Human Vaccine.

Gavi, the Vaccine Alliance (GAVI) announced on the same day it had signed two advance purchase agreements with Sinopharm and Sinovac to provide up to 550 million COVID-19 vaccines to the COVAX program.

The new deals include up to 170 million doses of the Sinopharm shot and up to 380 million shots of the Sinovac vaccine, through to the middle of 2022, the statement said. Sinovac confirmed the agreement in a statement.

"The agreements, which come at a time when the Delta variant is posing a rising risk to health systems, will begin to make 110 million doses immediately available to participants of the COVAX Facility, with options for additional doses," GAVI said.

GAVI, which runs the global vaccine sharing scheme COVAX with the World Health Organization (WHO) did not immediately provide details of which countries would receive the doses.

Deliveries can start quickly because both vaccines have already been granted emergency use listing by the WHO, CEO of GAVI Seth Berkley said.

COVAX, which distributes vaccines to poorer countries, has struggled to meet its early commitments amid Indian export disruptions, forcing many countries to freeze their inoculation programs in their early phases.

However, its latest supply forecast shows that the program is on track to deliver more than 2 billion doses by early 2022. The vaccines by Sinovac and Sinopharm join nine other vaccines and vaccine candidates already in the program including those by AstraZeneca and Moderna.

(With input from Reuters)