The chief of the World Health Organization on Wednesday highlighted China-Africa cooperation on fighting COVID-19 as the number of cases in the world exceeded 8 million.

Director-General Tedros Adhanom Ghebreyesus told a virtual news conference from Geneva that China has been supporting Africa since the pandemic started.

Tedros was speaking after the Extraordinary China-Africa Summit on Solidarity against COVID-19, a video link event co-hosted by China, South Africa and Senegal.

South Africa is the current chair of the African Union, and Senegal is the co-chair of the Forum on China-Africa Cooperation (FOCAC).

Tedros said that many African countries have talked about the kind of support they have been receiving from China, such as in sending experts, in sharing information and in providing supplies including COVID-19 test kits.

"It's not only the health part, they have also raised the issue of economic recovery, debt relief that China is willing to support with," Tedros said.

Tedros said the platform will be important in strengthening China-Africa relations and solidarity across the world.

He reiterated a call for more global solidarity. "(I would) like to use this opportunity to call on (the) unity, and solidarity of the whole world," he said.

In his speech at the meeting, President Xi Jinping said that "we must stay committed to fighting COVID-19 together. China will start ahead of schedule the construction of the Africa CDC headquarters this year".

"We must stay committed to enhancing China-Africa cooperation. Greater priority needs to be given to cooperation on public health, economic reopening, and people's livelihood," Xi said, as reported by the Xinhua News Agency.

Xi also said that "we must stay committed to upholding multilateralism. China will work with Africa to uphold the UN-centered global governance system and support WHO in making greater contribution to the global COVID-19 response."

"We must stay committed to taking China-Africa friendship forward," Xi said.

At the Wednesday press conference, Tedros credited the United Kingdom for its scientific breakthrough with a drug trial, saying the WHO welcomed the positive initial results from the trial of dexamethasone, a common steroid. He said the steroid has been shown to have a beneficial effect on those patients severely ill with COVID-19.

According to the early findings shared with the WHO, for patients on oxygen alone the treatment was shown to reduce mortality by about one fifth. And for patients requiring a ventilator, mortality was reduced by about one third.

However, dexamethasone was shown to not have a beneficial effect for those with milder disease, who did not need respiratory support, according to WHO.

"This is very welcome news for those patients with severe illness, these drugs should only be used under close clinical supervision," Tedros said.

"WHO has now started to coordinate a meta-analysis pooling data from several clinical trials to increase our overall understanding of this intervention."

Tedros added that the WHO will update its clinical guidance to reflect how and when dexamethasone should be used to treat COVID-19.