* 3 deaths in October after Prevenar vaccination

* Cause of deaths to be determined-Dutch health authority

* Suspended batch contains 110,000 doses (Adds details on vaccine)

AMSTERDAM, Nov 5 (Reuters) - Dutch authorities say they have banned use of a batch of Pfizer Inc's (PFE.N) Prevenar, or Prevnar, after three infants died within two weeks of receiving the anti-infection vaccination.

"On average about 5 to 10 deaths are reported annually after babies get vaccines," said a spokeswoman for the Dutch health institute RIVM.

"We now have three cases in a short period; that is unusual, and the reason for suspending the batch."

She said RIVM is investigating the cause of the infants' deaths. Other batches of Prevenar, known as Prevnar in the United States, will continue to be used.

Pfizer spokeswoman Gwen Fisher said preliminary investigations by the company and health authorities had found no link between the vaccinations and the deaths.

She said the company initiated the "quarantine" of the batch, which she said contained 110,000 doses of Prevenar, used to prevent pneumonia and related infections.

Fisher said the three infants also received two unrelated other vaccines as part of routine immunizations.

No other Prevenar batches were suspended, and infants in the Netherlands will continue to be vaccinated with it as part of routine immunization, she added.

A spokesman for the European Medicines Agency in London said its officials are working with the Dutch authorities to find out whether there were any safety issues with the vaccine batch.

The vaccine is one of the most widely used in the world and generated sales for U.S. drugmaker Wyeth of $2.7 billion in 2008.

Wyeth, which has just been acquired by U.S. rival Pfizer, had asked for the suspension of batch D66977 of Prevenar, RIVM said in a statement.

Pfizer is awaiting U.S. approval of a new form of the vaccine, called Prevnar 13, that would protect against additional strains of a bacterium called streptococcus pneumoniae that can cause an array of diseases, ranging from ear infections to pneumonia and meningitis.

Pfizer hopes to eventually seek approval of Prevnar 13 for adults, a new market that could ensure continued strong sales growth of the Prevnar franchise for years to come.

In late New York Stock Exchange trading, Pfizer shares were up 7 cents to $17.00. (Reporting by Gilbert Kreijger, with additional reporting by Ben Hirschler in London and Ransdell Pierson in New York; editing by Simon Jessop, David Cowell and Gerald E. McCormick)

A coalition of advocacy groups launched a campaign today opposing President Obama's choice of a pesticide industry official to represent U.S. interests in agricultural trade negotiations.

The 85 groups -- including Earthjustice, the Sierra Club, the Organic Consumers Association, the National Family Farm Coalition and dozens of state farm worker groups -- sent a letter today to the Senate Finance Committee opposing the nomination ahead of a scheduled confirmation hearing tomorrow for Islam Siddiqui.

The Pesticide Action Network also has an online petition that has gained more than 38,000 signatures against the nominee.

Obama tapped Siddiqui last month to be the chief agriculture negotiator in the Office of the U.S. Trade Representative. If confirmed, he would oversee farm negotiations at the World Trade Organization's stalled Doha Round.

A native of India, Siddiqui has years of experience in international trade and agricultural development. He held a number of agriculture posts in the Clinton administration, including senior trade adviser to the Agriculture Department. In that position, he worked with USTR and represented USDA in trade talks.

But the concern for environmentalists and farm activists is his advocacy for pesticides and biotechnology.

Siddiqui is currently vice president for science and regulatory affairs at CropLife America, a trade group that represents some manufacturers of pesticides and other agricultural chemicals.

CropLife America has been behind lawsuits challenging federal efforts to restrict pesticides and helped secure an exemption for U.S. farmers from a 2006 worldwide ban of methyl bromide, a chemical that depletes the stratospheric ozone layer.

The environmental and farming groups oppose statements that Siddiqui made during his previous tenure at USDA and as a lobbyist for CropLife. For instance, while at USDA in 1999, Siddiqui bashed the European Union's ban on hormone-treated beef and opposed a push for more stringent international labeling requirements for genetically modified crops, according to the groups.

In 1999, Siddiqui, then the special assistant for trade for USDA, was quoted saying, "We do not believe that obligatory [genetically modified organism] labeling is necessary, because it would suggest a health risk where there is none."

"Siddiqui's record and statements in his government positions and at CropLife America show his clear bias in favor of chemical-intensive and unproven biotechnology practices that imperil both our planet and human health while undermining food security and exacerbating climate change," the coalition told the Finance Committee. "We believe Siddiqi's nomination has severely weakened the Obama administration's credibility in promoting healthier and more sustainable local food systems here at home."

Earlier in his career, Siddiqui spent 28 years with the California Department of Food and Agriculture. Since 2004, he has served on an advisory committee on chemicals and health and science products for the Commerce Department and USTR. He studied agricultural biotechnology and food security issues as a senior associate at the the Center for Strategic and International Studies from 2001 to 2003.

Siddiqui received his bachelor's degree in plant protection from Uttar Pradesh Agricultural University in Pantnagar, India, and his master's and doctoral degrees in plant pathology from the University of Illinois, Champaign-Urbana.