Pfizer Inc. announced Monday Prevnar 13, its vaccine against childhood infections, prevented pneumonia in adults aged 65 and older in a recent drug trial, Reuters reported.

An 85,000-patient study - called CAPiTA - conducted in the Netherlands showed that the medicine also prevented invasive pneumococcal disease or infections of Streptococcus pneumonia bacteria in the bloodstream and other normally sterile sites in the body.

"We expect the [United States] and other developed markets to broadly recommend adult use of the product," given the favorable results, J.P. Morgan analyst Chris Schott said in a research note according to Reuters.

Wall Street analysts have predicted that annual sales of Prevnar 13 will increase by $1 billion or more, as a result of the success of the trial. The boost will largely come from doctors steering elderly patients to the product.

Schott said he expects Prevnar 13 sales among adults of $300 million in 2015, rising to $1.5 billion in future years as it is more widely used for that population.

In early 2010, the U.S. Food and Drug Administration approved Prevnar 13 to protect children against additional strains of Streptococcus pneumoniae bacteria that cause an array of diseases, including pneumonia, ear infections and meningitis.

In 2011 the federal agency broadened the use of Prevnar 13 by approving the use of the drug in adults aged 50 and older to prevent pneumonia and invasive infections. The approval was conditioned, however, on the success of the CAPiTA study.