(Bloomberg) -- Oil is poised for a fourth weekly advance, boosted by optimism over Covid-19 vaccine progress ahead of an OPEC+ ministerial gathering next week.Futures in New York are up nearly 8% this week, despite edging lower on Friday. The shape of the oil futures curve firmed over recent sessions as positive vaccine developments signaled the potential for a notable demand recovery next year.Meanwhile, Saudi Arabia and Russia have convened informal OPEC+ talks for Saturday, according to a letter. That will precede the formal ministerial meetings scheduled for Monday and Tuesday, where producers will decide whether to postpone a planned output hike.“With three vaccine candidates at least close to deployment, a material recovery in economic activity and oil consumption in the next six months is on the horizon,” said Erduan Reid, head of crude swaps at Eagle Commodities in London. If OPEC+ extends its current output cuts, “most balance estimates assume a first-quarter 2021 global draw driven by Asia, even if Europe and the U.S. build on mobility restrictions.”While most analysts surveyed by Bloomberg are forecasting OPEC+ will postpone the planned increase by three months to March, oil’s recent rally may further complicate the decision amid growing tension with some member countries. Meanwhile, Algeria, which holds the rotating OPEC presidency this year, said the group must remain cautious because the organization’s internal data point to the risk of a new oil surplus emerging next year. That’s if the cartel and its allies go ahead with a supply hike.“Some of OPEC’s members like the UAE and Iraq have expressed misgivings around the course of supply policy, and in part, we view this early meeting as a means to keep them in the OPEC+ fold and maintain group cohesion” said Harry Tchilinguirian, head of commodity markets strategy at BNP Paribas SA. “If the news that filters out over the weekend leans towards OPEC+ considering a delay to the tapering of its cuts, then we are likely to see the oil market continuing its advance.”The OPEC+ alliance’s agreement is expected to be in place throughout 2021 and the group will delay its planned tapering by three months, JPMorgan Chase & Co. analysts including Natasha Kaneva wrote in a report. The bank says inventories will decline by 1.2 million barrels a day on average next year, though demand still won’t reach normal levels until 2022.Alongside strong demand from Asia, there are signs consumption is gradually improving elsewhere. Foot traffic in U.S. airports hit the highest since March before the Thanksgiving holiday, though it remains about 1.5 million people lower year-over-year, according to data from the U.S. Transportation Security Administration. Healthy demand had helped flip the futures curve into a bullish backwardation structure this week, indicating tighter supplies.Still, in the near-term, there is the lingering threat of further lockdown measures due to the pandemic. Refiners globally will have to keep runs low until at least the second quarter of next year to prevent significant gasoline stockpile builds as lockdowns result in reduced mobility and weaker demand, according to a note from FGE. That’s as refiners continue to contend with razor-thin margins. The combined refining margin for gasoline and diesel is at its lowest seasonally since 2009.(Earlier version of this story corrected a source error in seventh paragraph.)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.