California identifies dengue case cluster in LA County

News brief

Los Angeles County Public Health yesterday announced that two more locally acquired dengue cases have been identified, raising the number in the cluster to three. The two latest patients are from Baldwin Park, the same area where the first case was reported last week.

The agency said though Aedes mosquitoes are common in Los Angeles County, local dengue cases are very rare. In 2023, two similar cases were reported, one in Long Beach and the other in Pasadena.

Concerning development

"This is a concerning number of locally acquired cases for a region where dengue has not been transmitted by mosquitoes," officials said on X yesterday.

The risk of widespread transmission in the country remains low, but officials are closely monitoring the situation, the health department said in its statement.

Health officials urged residents to take steps to avoid mosquito bites, such as wearing insect repellent, eliminating sources of standing water outdoors, and making sure screens on windows and doors are intact.

Over half of US kids infected with RSV in infancy, new data show

News brief

Stephanie Soucheray, MA

According to a US population-based birth cohort study in Emerging Infectious Diseases, 53.4% of babies were infected with respiratory syncytial virus (RSV) during infancy, and 2.8% were hospitalized.

The researchers also found that, among symptomatic infants, 44.1% had lower respiratory tract infections. The authors said these findings can act as a benchmark to monitor the effects of maternal vaccines and monoclonal antibodies administered to infants.

The study included 1,680 children up to 1 year old identified during two RSV seasons, 2012 to 2013 and 2013 to 2014. RSV infection was found via active surveillance using PCR testing of nasal samples based on symptoms, and by passive surveillance by serum RSV antibody testing of all children at 1 year of age.

Of the eligible infants, 897 (53.4%) were infected with RSV in the first year of life and 783 (46.6%) were not. Active surveillance detected 36.1% of RSV infections in symptomatic infants, and 63.9% were found by serology alone.

Findings provide benchmark

Among the 2.8% of infants hospitalized for RSV, 15.9% (95% confidence interval, 13.6% to 18.4%; n = 143) had RSV lower respiratory tract infections. There were no infant deaths from RSV infection.

Being born during RSV season, attending daycare, and having siblings were all associated with RSV infection.

Our data are important estimates of the burden of RSV disease and risk factors for infection in healthy term infants.

"Our data are important estimates of the burden of RSV disease and risk factors for infection in healthy term infants. Our findings provide a benchmark to monitor the effects in the United States of recently available maternal vaccines and extended half-life monoclonal antibodies for severe RSV illness prevention in early life," the authors concluded.