After a spring spike, the rate of positive rotavirus tests has been dropping across most of the United States. But the West is moving in the opposite direction, with test positivity climbing to nearly 9 percent as of early May, according to the latest CDC data.
Rotavirus is a highly contagious gastrointestinal infection that can be severe, especially in young children. Before vaccines became widely available, the virus caused tens of thousands of hospitalizations each year. Today, vaccination has cut that number dramatically, but outbreaks still occur, particularly among unvaccinated children aged 3 months to 3 years.
What Is Rotavirus?
The infection attacks the stomach and intestines, spreading through contact with infected stool. Symptoms include high fever, vomiting, and diarrhea that can be forceful and last up to a week. Dehydration is a serious risk, and there is no specific medication to treat the virus.
The Cleveland Clinic notes that unvaccinated toddlers are most vulnerable to severe illness. While most children recover with supportive care, hospitalization may be needed for hydration.
Vaccine History and Current Guidance
The first rotavirus vaccine, RotaShield, was pulled from the U.S. market in the late 1990s after being linked to a rare intestinal blockage. Two newer vaccines—RotaTeq and Rotarix—have been available since 2006 and 2008, respectively. Both are given as oral drops, with RotaTeq requiring three doses and Rotarix two.
The Trump administration previously altered guidance on the vaccine, but the CDC continues to recommend it as the best protection against rotavirus. The agency states the vaccine can prevent infection or reduce symptom severity.
Regional Trends: West Stands Out
National test positivity peaked at 7.25 percent in early April, slightly below the 7.45 percent recorded during the same period in 2024, but above the 5.34 percent from 2025. By the week ending May 2, the national rate had dipped below 6 percent.
Breaking down the data by region reveals a stark divergence. The Northeast, Midwest, and South all saw declines in test positivity between early April and early May. The West, however, jumped from 4.54 percent to 8.94 percent over the same period, even as the number of tests performed in the region dropped slightly.
Because rotavirus symptoms typically last about a week, most people who tested positive in early May are likely no longer ill. Still, the regional surge raises questions about vaccination coverage and public health messaging in Western states.
The CDC warns that even vaccinated children can contract rotavirus multiple times, though symptoms are usually milder. In addition to vaccination, health officials stress handwashing and good hygiene to limit spread.
For context, the recent trends in infectious disease surveillance have drawn comparisons to other outbreaks. For instance, Vibrio infections have surged as coastal waters warm, highlighting how environmental factors can shift disease patterns. Meanwhile, political debates over public health mandates continue to simmer, as seen in the Texas runoff testing MAGA loyalty. On the international front, Iran accuses the US of ceasefire breaches after fresh strikes in Hormozgan, underscoring the complex global landscape that health officials must navigate.
The CDC advises parents to ensure their children are up to date on rotavirus vaccination, especially in regions where the virus is circulating more widely.
