FDA releases draft guidance on antibiotic duration limits in food animals

News brief
Farmer feeding cows
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The US Food and Drug Administration (FDA) today published draft guidance for defining appropriate duration of use in antibiotics used in the feed of food-producing animals.

The guidance aims to address an issue that critics say the FDA has neglected in its efforts to promote more judicious use of medically important antibiotics in livestock and poultry. Roughly one-third of medically important antibiotics approved for use in food-producing animals have no duration limit, meaning farmers can use those antibiotics in animal feed for extended periods of time to prevent disease—a practice critics say compensates for poor living conditions that promote disease in herds and flocks.

Advocates for more robust antibiotic stewardship in US meat production say the overuse of medically important antibiotics on US farms promotes antibiotic resistance and threatens the effectiveness of antibiotics that are critical for human and veterinary medicine. Some groups have called for the FDA to limit the duration of use for medically important antibiotics to 21 days.

In a 5-year action plan released in 2018, the FDA's Center for Veterinary Medicine said that establishing appropriate duration limits would be one of its priorities.

Minimizing antibiotic exposure

The agency says the scope of the draft guidance is limited to drugs that are approved for use in animal feed, since antibiotics that have been approved in non-feed forms already have appropriately defined durations of use.

"FDA's objective in issuing this guidance is to provide specific recommendations to animal drug sponsors on how to revise the product use conditions (e.g., dosage regimen, instructions for use) of affected products, as necessary, to better target when and for how long a drug may be used to effectively treat, control, or prevent the disease(s) for which the product is indicated," the draft guidance states.

While compliance with the guidance is voluntary, the FDA says the revisions are, "intended to provide for the continued effective use of these products while minimizing the extent of antimicrobial drug exposure, thereby supporting efforts to mitigate the development of antimicrobial resistance."

The public comment period on the draft guidance is open until December 26.

Quick takes: Vectorborne infections in New Hampshire, more Florida dengue cases, UK-Seqirus pandemic vaccine deal

News brief
  • New Hampshire has reported its first Jamestown Canyon virus (JCV) infection of the year, which involves an adult from Hillsborough County, the state's health department announced yesterday. Also, officials reported two Powassan virus cases, one of them an adult patient from Rockingham County and the other a child from Carroll County. New Hampshire has now reported 13 JCV infections and 8 Powassan virus cases. JCV is spread by mosquitoes, and the United States averages about 23 neuroinvasive JCV cases each year, according to the Centers for Disease Control and Prevention (CDC).  Powassan virus is spread by black-legged ticks. Infections are rare, but are increasing, according to the CDC.black legged tick


  • Florida has reported eight more locally acquired dengue infections, raising the year's total to 31, the Florida Department of Health said in its latest weekly arbovirus surveillance report. Most (26) cases this year have been reported from Miami-Dade County, though a few were reported from Broward (3), Hardee (1), and Polk (1) counties.
  • The United Kingdom (UK) today announced an advance purchase deal with CSL Seqirus to produce 100 million vaccine doses if they are needed for an influenza pandemic. In a statement, the Health Security Agency said the UK has had similar standby agreements in the past, but the deal with Seqirus is the first to specify that the vaccines will be made in the UK, a step to ensure access if global demand outpaces supply, and to speed the delivery of doses. The doses would be produced at CSL's manufacturing plant in Liverpool.

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