Hopes of the emergence of a COVID-19 vaccine soon with Pfizer and BioNTech indicating a 90 percent effectiveness initial trial results sent the prices of crude oil benchmark soaring by 9 percent to more than $43 a barrel on Monday.

US pharmaceutical giant Pfizer and its German partner BioNTech conducted the said tests on over 40,000 people.

If approved for a US rollout this month, the pharmaceutical firms could globally supply up to 50 million doses this year and 1.3 billion next year.

However, it remains to be seen whether the vaccine can prevent severe disease or complications, how long it would remain effective if it works in the elderly.

The required safety data will be available only later this month.

Also, the data needs to be subjected to peer review by other scientists.

Another factor that pushed prices up was the OPEC+ alliance's effort to keep a tight grip on oil supply.

OPEC+ is due to restore 2 million barrels of oil per day to global markets from January.

However, Saudi Energy Minister Prince Abdul Aziz bin Salman's statement that they are "keeping flexibility" in their heads was interpreted by energy experts that they would maintain the current 7.7 million barrels of cuts per day for three months.