U.S. President Barack Obama, visiting a factory in Pennsylvania, will press his case on raising taxes on the wealthy to narrow the deficit. He is expected to make a statement around midday that is likely to impact markets.

"There is always hope in those situations that he (Obama) is going to announce some type of positive development," said Tim Ghriskey, chief investment officer of Solaris Group in Bedford Hills, New York. "We see how violently the market swings on positive and negative announcements."

Trading has been choppy as investors react to mixed statements from policymakers in Washington about discussions on averting the "fiscal cliff," spending cuts and tax hikes that will come into effect in the new year and could cause a recession, according to worst-case predictions.

Corporations continued to anticipate a harsher tax regime next year. Whole Foods Market Incwas the latest to announce a special cash dividend of $2.00 per share to skirt higher dividend tax rates in 2013. The stock was up 0.6 percent at $93.60.

The Dow Jones industrial average gained 5.63 points, or 0.04 percent, to 13,027.45. The Standard & Poor's 500 Index dropped 0.58 points, or 0.04 percent, to 1,415.37. The Nasdaq Composite Index dropped 3.43 points, or 0.11 percent, to 3,008.59.

The S&P 500 was on track to end the month 0.3 percent higher, after declining nearly 2 percent in October. The index has recovered 4.5 percent since shedding 8 percent following the U.S. presidential election earlier in November.

"The correction from the S&P 500's September peak has allowed overbought momentum and optimistic sentiment conditions to recede, and we believe the index is closer to an intermediate-term buy signal than a sell signal," said Ari Wald, analyst at PrinceRidge Group.

Yum Brands Incshares slumped 9.4 percent to $67.42. The company said late Thursday it expects fourth-quarter sales at established restaurants to drop in China, where a cooling economy is making it difficult to exceed the 21-percent gain it enjoyed there a year earlier.

After a close relationship for several years, Facebook Incand Zynga Increvised terms of a partnership agreement between the companies. Under the new pact, Zynga will have limited ability to promote its site on Facebook.

Zynga shares dropped 5.3 percent to $2.48. Facebook shares were down 1.2 percent at $26.99.

The markets' reaction to data on Friday was muted.

A report showed business activity in the U.S. Midwest expanded for the first time since August, buoyed by an improvement in the labor market.

Separately, data showed U.S. consumer spending fell in October for the first time in five months as income growth stalled, suggesting slower economic growth in the fourth quarter.

Apple Inc'slatest iPhone has received final clearance from Chinese regulators, paving the way for a December debut in a highly competitive market where the lack of a new model had severely eroded its share of product sales. Shares of Apple were down 0.7 percent at $585.29.

Verisign Incsaid the U.S. Department of Commerce had approved its agreement with ICANN to run the .com internet registry, but the company wouldn't be able to raise prices as before. The stock dropped 14.1 percent to $33.80 in late morning trading.

(Editing by Bernadette Baum)

That is a significant drop from a study last year done in slightly older children, which suggested the vaccine cut the malaria risk by about half though that is still far below the protection provided from most vaccines. According to details released on Friday, the three-shot regimen reduced malaria cases by about 30 percent in infants aged 6 to 12 weeks, the target age for immunization.

Dr. Jennifer Cohn, a medical coordinator at Doctors Without Borders, described the vaccine's protection levels as "unacceptably low." She was not linked to the study.

Scientists have been working for decades to develop a malaria vaccine, a complicated endeavor since the disease is caused by five different species of parasites. There has never been an effective vaccine against a parasite. Worldwide, there are several dozen malaria vaccine candidates being researched.

In 2006, a group of experts led by the World Health Organization said a malaria vaccine should cut the risk of severe disease and death by at least half and should last longer than one year. Malaria is spread by mosquitoes and kills more than 650,000 people every year, mostly young children and pregnant women in Africa. Without a vaccine, officials have focused on distributing insecticide-treated bed nets, spraying homes with pesticides and ensuring access to good medicines.

In the new study, scientists found babies who got three doses of the vaccine had about 30 percent fewer cases of malaria than those who didn't get immunized. The research included more than 6,500 infants in Africa. Experts also found the vaccine reduced the amount of severe malaria by about 26 percent, up to 14 months after the babies were immunized.

Scientists said they needed to analyze the data further to understand why the vaccine may be working differently in different regions. For example, babies born in areas with high levels of malaria might inherit some antibodies from their mothers which could interfere with any vaccination.

"Maybe we should be thinking of a first-generation vaccine that is targeted only for certain children," said Dr. Salim Abdulla of the Ifakara Health Institute in Tanzania, one of the study investigators.

Results were presented at a conference in South Africa on Friday and released online by the New England Journal of Medicine. The study is scheduled to continue until 2014 and is being paid for by GlaxoSmithKline and the PATH Malaria Vaccine Initiative.

"The results look bad now, but they will probably be worse later," said Adrian Hill of Oxford University, who is developing a competing malaria vaccine. He noted the study showed the Glaxo vaccine lost its potency after several months. Hill said the vaccine might be a hard sell, compared to other vaccines like those for meningitis and pneumococcal disease which are both effective and cheap.

"If it turns out to have a clear 30 percent efficacy, it is probably not worth it to implement this in Africa on a large scale," said Genton Blaise, a malaria expert at the Swiss Tropical and Public Health Institute in Basel, who also sits on a WHO advisory board.

Eleanor Riley of the London School of Hygiene and Tropical Medicine, said the vaccine might be useful if used together with other strategies, like bed nets. She was involved in an earlier study of the vaccine and had hoped for better results. "We're all a bit frustrated that it has proven so hard to make a malaria vaccine," she said. "The question is how much money are the funders willing to keep throwing at it."

Glaxo first developed the vaccine in 1987 and has invested $300 million in it so far.

WHO said it couldn't comment on the incomplete results and would wait until the trial was finished before drawing any conclusions.

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Online:

www.nejm.org

Campbell is considering scheduling more shows next year after playing more than 120 dates in 2012.

The 76-year-old singer has Alzheimer's disease and has begun to lose his memory. He put out his final studio album, "Ghost on the Canvas," in 2011 and embarked on the tour with family members and close friends serving in his band and staffing the tour.

Campbell's longtime manager Stan Schneider said in a phone interview from Napa, Calif., where the tour wrapped for the year Friday night, that recent West Coast shows have been some of the singer's strongest. Campbell will break for the holidays and if he still feels strong he'll begin scheduling more shows.

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Online:

http://glencampbellmusic.com