LA County Sees Uptick in Rotavirus Cases, Raising Concerns

Health officials warn of highly contagious virus that can lead to dehydration in young children

Apr. 17, 2026 at 11:38pm

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Health officials in Los Angeles County have detected an increase in rotavirus concentrations in wastewater, suggesting increased community transmission of the highly contagious virus. Rotavirus causes diarrhea, vomiting, and dehydration, particularly dangerous for infants and young children. While rotavirus cases have declined since a vaccine became available in 2006, low vaccination rates can still lead to outbreaks. The symptoms of rotavirus are similar to norovirus, another contagious stomach bug, making it difficult to distinguish between the two.

Why it matters

Rotavirus outbreaks can have serious consequences, especially for young children, leading to hospitalizations and emergency room visits. Understanding the spread of rotavirus in the community is important for public health officials to monitor and respond to potential outbreaks. Additionally, distinguishing between rotavirus and norovirus is crucial, as the two viruses require different prevention and treatment approaches.

The details

According to the Los Angeles County Department of Public Health, they have observed an increase in rotavirus concentrations in wastewater in recent weeks, indicating 'increased community transmission.' However, the overall concentrations of rotavirus remain far lower than the peak observed last June. The department noted that it is challenging to estimate the prevalence of rotavirus in the county, as the virus circulates year-round. Prior to the rotavirus vaccine becoming available in 2006, the disease resulted in hundreds of thousands of hospital and emergency room visits annually. While the vaccine has dramatically reduced the number of children getting sick with rotavirus, health officials warn that low vaccination rates can still lead to outbreaks.

  • In recent weeks, the LA County Department of Public Health has observed an increase in rotavirus concentrations in wastewater.
  • Prior to the rotavirus vaccine becoming available in 2006, the disease resulted in hundreds of thousands of hospital and emergency room visits annually.

The players

Los Angeles County Department of Public Health

The local public health department that has been monitoring the increase in rotavirus concentrations in the county's wastewater.

Centers for Disease Control and Prevention (CDC)

The national public health institute that provides information on the symptoms, transmission, and prevention of rotavirus.

California Department of Public Health

The state-level public health department that has data on the impact of the rotavirus vaccine in reducing the number of children getting sick with the virus.

Dr. Jeffrey D. Klausner

A professor of medicine and public health at the USC Keck School of Medicine who provided expert commentary on the symptoms and risks of rotavirus, especially for young children.

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What they’re saying

“Signs of dehydration could be tiredness. It could be excessive sleeping, could be just not playing or interacting.”

— Dr. Jeffrey D. Klausner, Professor of Medicine and Public Health, USC Keck School of Medicine

What’s next

Health officials in LA County will continue to monitor wastewater data and work to educate the public on the symptoms and prevention of rotavirus, especially for young children. Increasing vaccination rates could help reduce the risk of future outbreaks.

The takeaway

This uptick in rotavirus cases in LA County highlights the ongoing need for vigilance and public education around highly contagious viruses, even as vaccines have helped dramatically reduce their impact. Distinguishing between rotavirus and similar illnesses like norovirus is crucial for proper treatment and prevention efforts.