"We have a duty to rise to the challenge together during this summit and give a strong message of hope and reassurance," Saudi Arabia's King Salman said in the summit's opening remarks

While G-20 countries have contributed billions of dollars toward developing a vaccine for the virus, they have also mostly focused on securing their own vaccine supplies. Countries such as Britain, the US, France and Germany have negotiated deals with pharmaceutical companies to receive billions of doses, meaning that the vast majority of the world's vaccine supply next year is already reserved.

A day before the summit, UN Secretary-General Antonio Guterres said that while $10 billion has been invested in efforts to develop vaccines, diagnostics and therapeutics, another $28 billion is needed for mass manufacturing, procurement and delivery of new COVID-19 vaccines around the world.

Guterres called on more G-20 nations to join COVAX, an international initiative to distribute COVID-19 vaccines to countries worldwide. The United States has declined to join under President Donald Trump.

Trump highlighted what the US has done to respond to the coronavirus, rebuild the economy and work on vaccines. However he did not acknowledge that Joe Biden won this month's presidential election.

"It's been a great honour to work with you and I look forward to working with you again for a long time," Trump said, according to audio obtained by The Guardian.

The virus shows no signs of abating as major cities in the US and Europe bring back lockdowns and curfews. The World Health Organisation says more cases of COVID-19 have been reported in the past four weeks than in the first six months of the pandemic.

The International Labour Organisation says an equivalent of 225 million full-time jobs were lost in G-20 countries alone in the third quarter of 2020. G-20 member-countries represent around 85 per cent of the world's economic output and three-quarters of international trade..

In a video statement released ahead of the summit, UK Prime MInister Boris Johnson appealed to global leaders to harness the resources of the world's wealthiest nations to end the COVID-19 pandemic and tackle climate change.

"Our fates are in each other's hands," said Johnson, who is self-isolating at home in London after coming into contact with someone who tested positive for COVID-19.

It does not appear that any leaders dropped out of the summit, despite calls by rights groups, lawmakers and EU parliamentarians for leaders to boycott the gathering to protest Saudi Arabia's human rights record and war in Yemen.

G-20 heads of state last gathered virtually for an emergency meeting in March as the coronavirus was fast-spreading around the world. At the time, they vowed "to do whatever it takes to overcome the pandemic."

G-20 nations have since agreed to suspend debt payments for the world's poorest countries until mid-2021 to allow those nations to focus their spending on health care and stimulus programs. The UN secretary general, however, has called on the G-20 to extend debt repayment suspensions through the end of 2021 and expand the scope to middle-income countries in need.

Australian Associated Press