Gold fell on Monday en route to its worst month in four years, as optimism over a coronavirus vaccine-led economic revival prompted investors to buy into traditional risk assets.

Spot gold declined about 1 percent to $1,771.22 per ounce by 0452 GMT, shedding 5.7 percent so far this month – its biggest since November 2016.

US gold futures dropped 0.7 percent to $1,775.

“Vaccine-inspired optimism about an economic bounce is really eroding the attraction of safe-haven investments like gold,” said Michael McCarthy, chief strategist at CMC Markets, adding the metal’s fall below $1,800 was another trigger for the sell-off.

Vaccine optimism drove the dollar to a more than two-year low and put world stocks on course for a record month of gains.

“Gold looks bearishly biased and I don’t see any signal of a trend reversing anytime soon,” said Margaret Yang, a strategist at DailyFX.

Though gold has reached over-sold territory, the overall trend is so bearish that a technical rebound may not last for very long and be sustainable, she added.

Also bolstering risk-sentiment, data showed China’s factory activity expanded at the fastest pace in more than three years in November.

Investors now await congressional testimony by U.S. Federal Reserve Chairman Jerome Powell this week.

“The risks are the Fed will slow down or even halt its bond purchasing programme and that’s another reason to be cautious about the outlook for gold,” CMC’s McCarthy said.

Meanwhile, Citi said it expected bullion’s sell-off to taper in December with support in the mid-$1,700s.

“A renewed push above $2,000/oz in the next three-six months seems likely,” the bank said in a note, citing its bearish dollar outlook and low-interest rates as tailwinds.

Non-yielding gold, seen as an inflation hedge, benefits from lower interest rates that reduce its opportunity cost.

Silver slipped 2.9 percent to $22.03, platinum fell 0.5 percent to $959.13 and palladium was down 0.2 percent at $2,420.36.