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Since 2000, U.S. infants have been routinely immunized against pneumococcal (Streptococcus pneumoniae) infection, but the existing vaccine's expense puts it out of reach for most developing countries, where almost 1 million children die from pneumococcal infections each year. Richard Malley, MD, of the Division of Infectious Diseases at Children's Hospital Boston, is at work on a pneumococcal vaccine that meets developing countries' needs—it can be made cheaply, withstands high temperatures without refrigeration, and can be given without needles, avoiding the need for sterile procedures and medical professionals to administer it. Also, because it is a whole-cell vaccine, it should provide protection against virtually all of the 91 pneumococcal serotypes that infect people worldwide. (The U.S. vaccine covers only seven.)
Although a nasal form of the vaccine has already been tested in animals, there is concern that it may irritate infants' nasal passages and create breathing problems. Also, children in developing countries frequently have chronic nasal discharge and sinus infections, which may complicate nasal delivery. The laboratory is also investigating an oral vaccine, with promising results.
But more recently, Malley and his team have been funded to create a heat-withstanding skin patch that could be placed on infants' backs (safely out of reach) for several hours, immunizing them transdermally. If this works, similar patches could feasibly be developed for many other vaccines. "This is a revolutionary and simple way to administer vaccines," Malley says.
Preclinical studies of the patch in mice have had encouraging results. With human trials in mind, Malley's team is working with a Brazilian vaccine manufacturer to produce it under Good Manufacturing Practice, with support from the Program for Appropriate Technology in Health, a nonprofit group funded largely by the Bill and Melinda Gates Foundation.