LONDON: The dollar fell in early London trading on Friday and was on track for a weekly loss against a basket of currencies, even as the equity market rally ran out of steam as sentiment was hurt by doubts about AstraZeneca's COVID-19 vaccine.
The dollar has fallen more than 2.2pc so far this month as global market sentiment has surged on Joe Biden's U.S. election victory and news of progress in the development of COVID-19 vaccines, lessening demand for the safe-haven currency.
But sentiment became more mixed after several scientists raised doubts about the success rate for the vaccine developed by British drugmaker AstraZeneca.
AstraZeneca had said on Monday that its vaccine was 70pc effective in pivotal trials, and could be up to 90pc effective - the latest in a slew of positive vaccine announcements which had boosted investor confidence.
"Virus and vaccine news remain the main catalysts for markets as the US calendar is empty until Monday," ING strategists wrote in a note to clients.
"All in all, risk sentiment still appears in stabilization mode, and the dollar may keep oscillating around 2-year lows (the 92.00 level for DXY) today due to the lack of clear catalysts and reduced trading volumes," they said.
At 0831 GMT, the dollar was at 91.953 versus a basket of currencies, down 0.1pc on the day and close to its lowest in three months.
Market price-action was limited on Thursday by the Thanksgiving holiday in the United States, which will be operating on reduced trading hours on Friday.
The Australian dollar - a liquid proxy for risk - hit its highest in nearly three months in early London trading and was up 0.2pc at 0.7375 at 0834 GMT.
Australia's second-largest state, Victoria, which was once the country's COVID-19 hotspot, said on Friday that it has gone 28 days without detecting new infections.
The Kiwi dollar, which is having its best month since late 2013, was up 0.1pc on the day at 0.7019.
"Clearly, the biggest single risk for financial markets now is the failure of vaccines being rolled out smoothly in Q1 2021," wrote MUFG strategist Derek Halpenny.
"The other key risk that also continues to be ignored is the ongoing surge in COVID infections and deaths in the US," he said, adding that if President-elect Joe Biden brings in new lockdown restrictions while the rest of the world is recovering next year then that provide a further reason to sell the dollar.
Dollar-yen was down 0.2pc at 104.03 at 0836 GMT. China's offshore yuan was on track for its first week of net losses versus the dollar this month.
The euro was up 0.1pc at $1.1925, having shown little reaction to downbeat comments from the European Central Bank's chief economist Philip Lane on Thursday.
Elsewhere, the pound was steady at $1.3369 as UK investors watched Brexit negotiations for signs of progress.
The European Union's chief negotiator said he would travel to London later on Friday to continue talks. Euro-sterling was steady at 89.22 pence per euro at 0844 GMT.
Bitcoin, which stabilised overnight after wiping off more than a week's worth of gains on Thursday, was starting to fall again in early London trading, but less steeply than in the previous session.