About

About RSV:

Respiratory syncytial virus (or RSV) is a common virus (germ) that causes respiratory illnesses like bronchiolitis and pneumonia. RSV infections generally occur during the fall, winter, and spring, and nearly all children will have an RSV infection at least once by their second birthday. In older children, RSV usually causes a cough or cold-like symptoms. In infants, especially those less than six months old, RSV infection can cause severe inflammation of the airways that may require hospitalization. Some children develop wheezing or asthma that continues for years after the RSV infection is over.

Rates of RSV in American Indian and Alaska Native (AI/AN) children have historically been very high. Prior to the availability of RSV prevention products, 1 in 10 Native American babies in the Southwest United States was hospitalized with RSV each year.

Two shots to prevent RSV in children were introduced in 2023. One, called nirsevimab is for children, and one, called RSVpreF vaccine, is for pregnant women. There is also an RSV vaccine for older adults.

What the study involved: The RSV-SuNA study, funded by the Centers for Disease Control and Prevention, measured the amount of RSV and other respiratory viruses causing respiratory illness in the Navajo Nation, White Mountain Apache Tribal Lands, and in Alaska. This study began in 2019 and ended in May 2025. We enrolled children <5 years who were hospitalized (inpatients) or had an outpatient visit (for example, a clinic visit or visit to urgent care) with a respiratory infection. Some study locations also enrolled adults. The study took place at health facilities in Navajo Nation (Chinle, Fort Defiance, Gallup, Tuba City), the White Mountain Apache Tribal lands, and Alaska, and participation was voluntary. Following informed consent, we collected a nasal swab to test for respiratory viruses. We also asked about the patient’s illness and their household, and we looked at medical conditions and information about the illness in the medical chart.

What was learned:

  • In the first year of the study, 2019-2020, the rates of RSV hospitalization among AI/AN children under 2 years at the different study sites in the Southwest and Alaska were 3 to 8 times higher than US national rates. During the first year of the COVID pandemic, when there were lockdowns and mask requirements, there was very little circulation of RSV. RSV rebounded and in 2022-2023, before RSV prevention products were available, RSV was found in more than half of respiratory hospitalizations among AI/AN children in the study, followed by COVID-19, rhinovirus, human metapneumovirus, and influenza.
  • In 2024, the RSV monoclonal antibody, nirsevimab, was recommended for routine use for all U.S. infants <8 months who were born during or entering their first RSV season. In the U.S. nirsevimab is also recommended for children 8-19 months who are at increased risk for severe RSV disease, including AI/AN children. This decision was based in part on data from the RSV-SuNA study, which showed very high rates of RSV hospitalization in AI/AN children in the second year of life.
  • The RSV-SuNA study has also found that the RSV monoclonal antibody, nirsevimab, is highly effective in preventing RSV hospitalizations in AI/AN children. Analyses are ongoing to evaluate the effectiveness of the maternal RSV (RSVpreF) vaccine in this population.
  • These data can be used by the Tribes to understand the burden of RSV and to guide use of RSV immunizations to improve the health of the population.

 

We thank all study participants, IHS and tribal health facility medical staff, community members, the tribal ethical review boards, and the Centers for Disease Control and Prevention for making this study possible.

IRB #: NNHRRB NNR-19.350; PHX Area IRB 19.08; JHSPH IRB No. 00009605