Washington: US pharmaceutical giant Pfizer said tests involving more than 40,000 people had provided results that were a "critical milestone" in the search for a vaccine, as global infections soared past 50 million - including an alarming 10 million now in the United States alone.
Stock markets had already jumped after Democrat Joe Biden was called as the winner of the US presidential election on the weekend. They accelerated rapidly on the vaccine news, with the Dow Jones Industrial Average up three percent at Monday's close of trade.
An effective vaccine is seen as the best hope to break the cycle of deadly virus surges followed by severe restrictions across much of the world since COVID-19 first emerged in China late last year.
"We are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis," Pfizer chairman Albert Bourla said in a statement.
The drug, being developed jointly with German firm BioNTech, is one of more than 40 candidate vaccines, but no other has yet made similar claims about its effectiveness.
The companies said they could pass the final hurdles for a US rollout later this month, and could supply up to 50 million doses globally this year and up to 1.3 billion next year.
The scientific community reacted positively, with top US expert Anthony Fauci describing the results as "extraordinary."
World Health Organization director Tedros Adhanom Ghebreyesus hailed the news as "encouraging" shortly after warning that the world "might be tired of Covid-19. But it is not tired of us."
But others pointed out that no information had yet been disclosed about the ages of the participants in the trial.
"If a vaccine is to reduce severe disease and death, and thus enable the population at large to return to their normal day-to-day lives, it will need to be effective in older and elderly members of our society," said Eleanor Riley, professor of immunology and infectious diseases at the University of Edinburgh.
Winners and losers on the share market
Airlines, suffering their worst-ever crisis, led the way, with Japan Airlines cruising up 20 percent, Singapore Airlines flying 14 percent and Cathay Pacific rocketing more than 11 percent on hopes people will be able to get back in the air.
Bets on a rebound in the gambling sector ramped up as Hong Kong-listed Macau casino operators piled on the cash - as well as Wynn's rally, Sands China put on nearly seven percent and Galaxy Entertainment surged five percent.
Genting Singapore, which operates a casino and a Universal Studios theme park in the city-state, chalked up more than seven percent.
Expectations that demand will pick up as people travel more pushed energy firms higher, with Hong Kong-listed CNOOC up more than 12 percent and Papua New Guinea-focused Oil Search putting on 16 percent in Sydney.
Property developers were also winners with Singapore-traded CapitaLand putting on about four percent while Hong Kong's New World Development moved up more than five percent.
However, there were also big losers - firms that have enjoyed large gains for most of the year thanks to the surge in demand for medical equipment to treat the virus and technology from people stuck at home in lockdowns.
Malaysia's Top Glove, the world's biggest maker of surgical gloves, fell more than eight percent in Kuala Lumpur - though that was a small bite out of the more than 400 percent rise it has enjoyed since the start of the year.
Another glove manufacturer, Supermax, cratered more than eight percent in Malaysia, having racked up gains of more than 1,100 percent in the past 10 months.
Meanwhile, gaming giants were deep in the red, just as the sector prepares for the holiday season and the next era of computer consoles with Microsoft putting its new Xbox on sale.
Sony, which puts its PlayStation 5 on shelves Thursday, shed three percent in Tokyo while rival Nintendo dropped more than two percent.
Nintendo has climbed around 25 percent this year while Sony was up about 20 percent.
And China's Tencent, one of the world's largest computer game makers, slipped more than three percent in Hong Kong - a fraction of the 60 percent gain it has enjoyed in 2020.
OANDA's Halley said more positive news on vaccines may come in the following weeks, but also sounded a note of caution.
COVID-19 cases spike in Europe
The vaccine news will be of particular relief to people in Europe - the current focal point of the pandemic and the region subject to the most widespread restrictions.
The European Union said Monday it could soon sign a contract with Pfizer and BioNTech for 300 million doses of the new coronavirus vaccine.
"European science works!" declared Ursula von der Leyen, the president of the European Commission, congratulating the companies after they claimed a breakthrough.
On Monday, Ukrainian President Volodymyr Zelensky became the latest leader to test positive for the virus, with his office saying he felt well and would self-isolate and continue to work.
Italy was edging closer to a full lockdown, with experts warning of pressure on hospitals.
"There is no doubt that the situation is largely out of control," said Massimo Galli, head of the infectious diseases department at Milan's Sacco hospital.
Grim news kept coming elsewhere, with Russia surpassing its record for daily infections again Monday.
Hungary is now one of the hardest-hit countries in terms of deaths proportionate to its population, and the government announced new national restrictions to come into force Wednesday.
Portugal meanwhile entered a state of emergency that will see curfews imposed on most of the population.
In France, which has imposed nationwide stay-at-home orders and is clocking more than 40,000 cases a day, the central bank revised its expectations of the damage wrought by the curbs.
"Before the second wave, we thought the recession would be a little less than nine percent, we think today that for 2020 as a whole it will be between nine and 10 percent," Banque de France chief Francois Villeroy de Galhau said.
Meanwhile, vaccine development took a hit Monday when Brazil's health regulator announced it had suspended clinical trials of a Chinese-developed COVID-19 vaccine - one of the most advanced vaccine candidates - after an "adverse incident" involving a volunteer recipient.
- Bloomberg, AFP