Vaccine under development provides the “most comprehensive coverage” to date and alleviates antimicrobial concerns, new study finds.

In 2004, pneumonia killed more than 2 million children worldwide, according to the World Health Organization. By 2015, the number was less than 1 million.

Better access to antibiotics and improved nutrition account for part of the decline. But scientists say it’s mostly due to vaccines introduced in the early 2000s that target up to 23 of the most deadly forms of the bacterium that causes pneumonia, Streptococcus pneumoniae.

Now, a new vaccine under development could deal another blow to the disease, lowering the number of deaths even further by targeting dozens of additional strains of S. pneumoniae, and anticipating future versions of the bacteria responsible for the disease.

The vaccine provoked an immune response to 72 forms of S. pneumoniae — including the 23 mentioned above — in lab tests on animals, according to new research published October 20, 2017, in the journal Science Advances. The study represents the “most comprehensive” coverage of pneumococcal disease to date, researchers said.

“We’ve made tremendous progress fighting the spread of pneumonia, especially among children. But if we’re ever going to rid ourselves of the disease, we need to create smarter and more cost-effective vaccines,” said Blaine Pfeifer, PhD, associate professor of chemical and biological engineering at the University at Buffalo’s School of Engineering and Applied Sciences, and the study’s co-lead author.

Each strain of S. pneumoniae contains unique polysaccharides. Vaccines such as Prevnar 13 and Synflorix connect these sugars — by the sharing of an electron — to a protein called CRM197. The process, known as a covalent bond, creates a potent vaccine that prompts the body to find and destroy bacteria before it colonizes the body.

While effective, creating covalent bonds for each strain of S. pneumoniae is time-consuming and expensive. Plus, this type of immunization, known as a conjugate vaccine, prompts the body to eliminate each of the targeted bacteria types — regardless of whether the bacteria is idyll or attacking the body.

Another vaccine, Pneumovax 23, contains sugars of 23 of the most common types S. pneumoniae. However, the immune response it provokes is not as strong as Prevnar because the sugars are not covalently linked.

“Traditional vaccines completely remove bacteria from the body. But we now know that bacteria — and in a larger sense, the microbiome — are beneficial to maintaining good health, said Charles H. Jones, the study’s other co-lead author.

“What’s really exciting is that we now have the ability — with the vaccine we’re developing — to watch over bacteria and attack it only if it breaks away from the colony to cause an illness. That’s important because if we leave the harmless bacteria in place, it prevents other harmful bacteria from filling that space.”

Jones, who earned a PhD while working in Pfeifer’s lab, has formed a company, Abcombi Biosciences, to bring the vaccine and other pharmaceutical products to market. The company is part of the START-UP NY economic development program, was a finalist for the 43North business plan competition in 2016 and has received seed funding and other support from UB.

Co-authors of the study from UB’s engineering school include Guojian Zhang, Roozbeh Nayerhoda, Marie Beitelshees (also of Abcombi), Andrew Hill (also of Abcombi) and Yi Li; Bruce A. Davison and Paul Knight III, both faculty members from the Jacobs School of Medicine and Biomedical Sciences at UB; and Pooya Rostami of New York University’s Langone Medical Center.

Varieties of S. pneumoniae not covered by current immunizations are responsible for a small portion — for example, 7 to 10 percent among U.S. children, accordi