Monday's midday trade: Wall Street's main indexes upbeat

• Alibaba sinks on Chinese regulatory ire

• Cruise ship, airline operators gain

• Alexion Pharma among top boosts on AstraZeneca offer

NEW YORK: Wall Street's main indexes rose on Monday as consumer stocks surged on the launch of a nationwide Covid-19 vaccine campaign, while Alexion Pharmaceuticals jumped on a $39 billion buyout offer from AstraZeneca in one of the year's biggest deals.

Administration of the vaccine developed by Pfizer and its German partner BioNTech began on Monday, after the shot received emergency-use approval from federal regulators last week.

The inoculations are seen as pivotal toward ultimately halting the Covid-19 pandemic, which has claimed more than a million lives around the world and brought economic activity to a halt.

Consumer discretionary stocks were among the best performing sectors on the S&P 500 on Monday, while travel and leisure stocks, which are among the worst hit by the virus outbreak, also gained.

Cruise operator Carnival Corp rose 0.8%, while American Airlines Group added 0.3%.

Alexion Pharmaceuticals Inc was among the top boosts to the S&P 500 and the Nasdaq, surging 31.0% to a 4-1/2 year high after British drugmaker AstraZeneca said it would buy the US biotech firm. AstraZeneca's US-listed shares fell 6.1%.

"It is a sign that animal spirits are back ... companies are reluctant to do deals when they have a negative outlook on the future, but the fact that you are seeing these types of big deals on merger Mondays is a sign of things to come," said Thomas Hayes, managing member at Great Hill Capital Llc in New York.

At 12:00 p.m. ET, the Dow Jones Industrial Average was up 63.55 points, or 0.21%, at 30,109.92, the S&P 500 was up 13.59 points, or 0.37%, at 3,677.05. The Nasdaq Composite was up 144.87 points, or 1.17%, at 12,522.74.

Uncertainty over more fiscal stimulus had cut short a recent rally in US stocks, after the Senate last week approved a one-week extension of federal funding to avoid a government shutdown and to provide more time for negotiations on coronavirus relief and an overarching spending bill.

"Equities have performed very strongly in what has been a very difficult economic environment ... there is some vulnerability there if the market concludes that fiscal support is at its end," Eric Winograd, senior economist at AllianceBernstein told the Reuters Global Market Forum.

Focus was also on early voting in a pair of US Senate races in Georgia that will determine control of the chamber and heavily influence lawmaking.

E-commerce company Alibaba Group Holding Ltd shed 2.6% after China warned its internet majors of more anti-trust scrutiny, slapped fines and announced probes into deals involving Alibaba and Tencent Holdings Ltd.

Electric-car maker Tesla Inc rose 4% as anticipation of the firm's addition to the S&P 500 benchmark next week offset a report of production delays.

Walt Disney Co fell about 2.7% after rallying on Friday and was the biggest drag on the Dow after BMO Capital Markets downgraded the stock. The S&P index recorded 25 new 52-week highs and no new low, while the Nasdaq recorded 196 new highs and 11 new lows.