Active Bacterial Surveillance (ABS) in Communities in the Southwest

About

Brief study summary

The Active Bacterial Surveillance (ABS) system provides Navajo Nation and White Mountain Apache Tribal lands with active monitoring for cases of severe disease caused by four different types of bacteria (“germs”).

Study background

Streptococcus pneumoniae, or “Pneumo,” is a germ that can cause illnesses ranging from sinus infections to pneumonia and blood infections. Native American adults are disproportionately affected by serious Pneumo disease. Although several safe and effective licensed vaccines, such as Prevnar20 (PCV20) and Capvaxive (PCV21), protect against some strains, other strains are present on Navajo Nation and White Mountain Apache Tribal lands and are causing illness in some adults. A vaccine called VAX-31, which was developed to protect against more strains of Pneumo, may offer enhanced protection.

What are we doing?

We collaborate with 24 Indian Health Service, Tribal Health Organization, and private labs serving Navajo Nation and White Mountain Apache communities to monitor severe (invasive) disease caused by:

Haemophilus influenzae
Streptococcus pneumoniae
Neisseria meningitidis
Group A Streptococcus (Streptococcus pyogenes)
Staphylococcus aureus (currently paused, but was active from 2016-2024)

The surveillance system is active- and laboratory-based. This means that our team regularly contacts lab staff, but we don’t have contact with patients. When a case is identified by the lab, we:

Collect a copy of the germ to see what strain it is and if it is resistant to any antibiotics.
Collect demographic and clinical information on the case so we can describe the type and severity of illnesses that are occurring and risk factors for illness.

Some recent findings:

ABS has shown how vaccines have drastically reduced severe disease among children
- Use of H. influenzae type b (Hib) vaccine and pneumococcal conjugate vaccines in Navajo Nation led to a more than 95% reduction in these diseases in children <5 years of age
ABS has shown that a certain type of vaccine-preventable S. pneumoniae called “serotype 4” has caused 20-35% of severe pneumococcal disease in Navajo Nation since 2022
- Serotype 4 is mainly affecting unvaccinated men aged 18-49 years
- Findings from ABS led IHS to issue a call to increase pneumococcal vaccination among eligible adults and helped providers to know which of several available pneumococcal vaccines was best for Navajo Nation and White Mountain Apache Tribal lands.
ABS has shown that the incidence of severe Group A Streptococcus (Strep A) disease in Navajo Nation and White Mountain Apache Tribal lands is more than 5 times higher compared to the general US. Knowing this and the strains of Strep A that are causing disease here helps to ensure that Strep A vaccines that are developed will protect against the types of Strep A we see.

How will this help improve health in your community?

Public health surveillance programs like ABS are important to track diseases over time. This helps us:

Recognize disease outbreaks
Understand the impact of prevention measures (like vaccines or communication/educational campaigns)
Identify opportunities for improving prevention measures and reducing the burden of disease in our communities

Principal Investigator/Program Coordinator information

Laura Hammitt lhammitt@jhu.edu

Publications

Sutcliffe, C. G., Littlepage, S., Yazzie, D., Brasinikas, G., Christensen, L., Damon, S., Denny, E., Dixon, S. L., Grant, L. R., Harker-Jones, M., McAuley, J., Montanez, P., Parker, D., Reasonover, A., Rice, A., Roessler, K., Romancito, E., Salabye, C., Sergent, V. M., Simons-Petrusa, B., … Hammitt, L. L. (2025). Impact of the COVID-19 pandemic on invasive pneumococcal disease in American Indian communities in the Southwest US. Journal of medical microbiology, 74(3), 001983. https://doi.org/10.1099/jmm.0.001983
Sergent VM, Sutcliffe CG, Yazzie D, Brasinikas G, Brown LB, Christensen L, Clichee D, Damon S, Dixon SL, Grant LR, Harker-Jones M, McAuley JB, Montanez P, Parker Riley D, Reasonover A, Rice A, Romancito E, Salabye C, Simons-Petrusa B, Tenequer VL, Thompson P, Tsingine M, Tso C, Weatherholtz RC, Hammitt LL. Impact of Pneumococcal Conjugate Vaccines on Otitis Media among American Indian/Alaska Native Children in the Southwest United States. J Pediatric Infect Dis Soc. 2025 Mar 12;14(3):piaf013. doi: 10.1093/jpids/piaf013. PMID: 39957289.
Sutcliffe, C. G., Sergent, V. M., Yazzie, D., Brasinikas, G., Christensen, L., Clark, M., Cowboy, W., Dixon, S. L., Grant, L. R., Harker-Jones, M., Hurley, C., Iralu, J. V., McAuley, J. B., Miernyk, K., Montanez, P., Rice, A., Romancito, E., Salabye, C., Simons-Petrusa, B., . . . Hammitt, L. L. (2026). Post-COVID Rebound in Invasive Pneumococcal Disease Driven by Resurgence of Serotype 4 Among American Indian Individuals in the Southwest United States. The Journal of Infectious Diseases. https://doi.org/10.1093/infdis/jiag285

Additional Information

**Sign up for our Active Bacterial Surveillance Newsletter**

Regular reports for the Navajo Nation can be found on the Navajo Epidemiology Center’s website: https://nec.navajo-nsn.gov/Projects-Reports/Infectious-Disease