Oil prices increased over 1% on Monday, expanding last week’s gains as traders eyed a recovery in demand due to successful coronavirus vaccine trials.Sentiment was also strengthened by expectations that the Organization of the Petroleum Exporting Countries (OPEC), Russia and other producers, a group known as OPEC+, may extend a deal to restrain output.Brent crude increased 94 cents to $45.90 a barrel by 0913 GMT while US West Texas Intermediate crude increased 76 cents to $43.18 a barrel. Both benchmarks leaped 5% last week.The contango structure in the market, where the prices of front-month delivery contracts are less than those for delivery six months later, reduced to 32 US cents, its smallest since mid June, showing that concerns due to glut were retreating.