Current vaccines target only a small percentage of the more than 90 strains of the bacteria that cause pneumonia. But researchers say a new protein-based vaccine can defend against many more strains—and that it’s 100 percent effective at promoting the appropriate immune response.
Computer simulations indicate the vaccine would be effective against all strains of pneumococcus, but additional tests are needed to confirm that.
The vaccine offers what could be the most direct and broad response to preventing pneumonia—the leading cause of death of children under the age of 5 worldwide, according to the World Health Organization—as well as meningitis, sepsis, and other serious infections caused by pneumococcus.
“These are very serious illnesses that we haven’t been able to completely suppress. The vaccine we’re developing could finally get that job done,” says Blaine A. Pfeifer, an associate professor of chemical and biological engineering at the University at Buffalo School of Engineering and Applied Sciences.
Pfeifer led the study, published in the Proceedings of the National Academy of Sciences, with former student Charles H. Jones, who is overseeing efforts to commercialize the vaccine.
“With conventional vaccines, the approach has been: ‘What bacteria do we want to target and how,'” says Jones, CEO and founder of Abcombi Biosciences. “Our strategy is to shift the paradigm to which diseases do we want to prevent.”
To treat and prevent illnesses caused by pneumococcus, doctors almost exclusively relied on penicillin and other common antibiotics. While still used, the effectiveness of these drugs has been waning for decades due to bacteria developing antibiotic resistance.
The situation led pharmaceutical companies to develop preventative vaccines, which have reduced deaths and illnesses, especially in developed nations. But pneumococcus remains a serious problem.
Pneumonia killed 1.3 million people worldwide in 2011, with the majority of deaths in Sub-Saharan Africa and South Asia. In the United States alone, pneumonia, meningitis, and sepsis cause tens of thousands of deaths each year, according to the National Foundation for Infectious Diseases.
One reason for this is that current vaccines, which identify pneumococcus by a sugar coating that surround the bacteria, are 56 to 88 percent effective.
Why this vaccine is different
The new vaccine identifies strains by proteins attached to the surface of pneumococcus. Laboratory tests show the vaccine can defend against more than 12 strains.
“It’s like the arcade game Whac-A-Mole. Think of the mallet as a traditional vaccine. It can’t stop all the moles, or in our case, all the strains of bacteria at once,” Jones says. “But our vaccine does just that. It’s like a mallet with 90 heads that strikes all the moles simultaneously.”
The new vaccine also differs from what’s on the market by its response to the bacteria.
Current vaccines teach the immune system to indiscriminately destroy bacteria and other pathogens. The approach works, but there is growing concern that it can create space within the body for new and potentially more harmful alternatives to establish residence—similar to antibiotic resistance resulting in new and more potent pathogens.
The new vaccine allows bacteria to exist as long as it causes no harm to body. It instructs the immune system to attack only when the surface proteins, mentioned above, break free of the bacterial coating.
“That’s the signal that this bacteria is becoming a troublemaker, that’s its threatening the body, and that it’s necessary to fight back,” Pfeifer says.
The National Institutes of Health, Swedish Medical Research Council, and the Arthur A. Schomburg Fellowship Program at the University at Buffalo funded the work.
Source: University at Buffalo