The Centers for Disease Control and Prevention (CDC) today warned clinicians about errors in respiratory syncytial virus (RSV) administration in young children and pregnant women, which follows the release of two newly approved RSV vaccines for adults and an injectable RSV monoclonal antibody preventive called nirsevimab (Beyfortus) for babies and young children.

The errors were reported through the CDC's Vaccine Adverse Event Reporting System (VAERS). The CDC described the situation in a COCA Now clinician outreach email.

The events involving children younger than 2 years old who received Pfizer's Abrysvo or GSK's Arexvy were rare, with 25 such cases reported. Most occurred in babies younger than 8 months and in outpatient settings.

Meanwhile, about 128 instances of pregnant women mistakenly getting Arexvy were reported, also most commonly reported in outpatient settings, including pharmacies. Abrysvo is the only RSV vaccine recommended for pregnant women as a tool for protecting young babies from RSV infection.

In its notice to clinicians, the CDC said most administration errors described no adverse events, and when adverse events did occur, they were recorded in VAERS as nonserious.

"CDC, FDA, and other federal agencies continue to monitor the safety of RSV vaccines and reports of vaccine administration errors and will share information with the public as it becomes available," the CDC said. The group also issued recommendations for clinicians who have administered the incorrect vaccine, including that children who got one of the two RSV vaccines receive a dose of Beyfortus and that babies of pregnant women who mistakenly got Arexvy get Beyfortus during RSV season if younger than 8 months.

Early use of tecovirimat, known as Tpoxx, an antiviral used in mpox infections, leads to a subjective improvement in symptoms, according to a new study in Open Forum Infectious Diseases.

The small study was based on outcomes seen in mpox patients identified in King County, Washington, from May to October 2022. Of 465 individuals diagnosed with mpox during the study period, 115 (25%) participated in this study.

Outcomes were compared among those who started taking tecovirimat 5 or fewer days after symptom onset and those who began 6 to 28 days after symptom onset.

A subjective sense of earlier resolution in symptoms was seen among those who started the antiviral 5 days or less after first becoming symptomatic, but only if the patient experienced severe symptoms, defined as proctitis, rectal bleeding, and severe pain.

Given the potential benefit of early treatment in severe disease, providers could consider offering tecovirimat prior to laboratory-confirmation.

In a multivariable analysis, early tecovirimat was associated with shorter time to symptom improvement (-5.5 days) among participants with severe illness but not among those with non-severe illness (1 days). Early tecovirimat was not associated with faster illness resolution, regardless of severity, the authors wrote.

The researchers called for a randomized controlled trial to clarify the study results and said the present findings could be due to small numbers in stratified groups and limited power or from tecovirimat slowing progression, but not hastening, resolution of mpox.

"Given the potential benefit of early treatment in severe disease, providers could consider offering tecovirimat prior to laboratory-confirmation, particularly as data suggests that well-trained sexual health clinic providers can accurately diagnose mpox prior to laboratory confirmation," the authors wrote.

The Centers for Disease Control and Prevention (CDC) confirmed 105 new Salmonella cases (407 total) in an outbreak linked to tainted cantaloupe but declared its investigation into the outbreak over.

The CDC first notified the public of the outbreak on November 17, 2023. Since then, 6 people have died (2 more since the most recent update in December), and 158 people have been hospitalized in an outbreak that spanned 44 states and included a recall of several fruit products, including whole-fruit Malichita brand cantaloupes from Mexico.

Eventually, pre-cut melon products were recalled from Kwik Trip, Kroger, Sprouts Farmers Market, and Trader Joe’s, as well.

Last case reported December 25

Illnesses started on dates ranging from October 15 to December 25, 2023, the CDC said.

The true number of sick people in this outbreak was likely much higher than the number reported.

"The true number of sick people in this outbreak was likely much higher than the number reported, and the outbreak may not have been limited to the states with known illnesses," the CDC said.

The median age of those sickened was 60 years, 26% were 5 years or younger, and 47% were 65 years or older. In epidemiologic interviews, 69% of those sickened reported eating cantaloupe in the weeks before illness. Several people have also been sickened in Canada.

Included in the outbreak were both residents at long-term care facilities and children in daycare centers. The elderly and the very young are the most likely to suffer from severe Salmonella infections.