What CDC Is Doing to Respond to Bird Flu Outbreaks in Dairy Cows and Other Animals in the United States

CDC is working with USDA and state partners to monitor for infections in exposed persons in the states where detections in poultry, backyard flocks, or other animals have occurred.

• People who have been exposed to infected birds, poultry, or other animals are actively monitored for 10 days after exposure.
• Public health departments are working to monitor people who were exposed to birds/poultry or other animals infected with A(H5N1) virus.
• People monitored who show symptoms are subsequently tested for novel influenza A and seasonal flu viruses along with other respiratory viruses.
• CDC is engaging public health partner organizations to share information and ensure preparedness for any potential human infections.

CDC continues to support surveillance, contact tracing, and other steps to monitor for and reduce spread in jurisdictions where human infections with A(H5N1) virus are identified.

Genetic Sequencing and Virus Characterization

CDC will continue its ongoing assessment of the risk posed by these viruses, including conducting additional laboratory work to further characterize current A(H5N1) viruses.

Because flu viruses are constantly changing, CDC continually analyzes viruses to identify genetic changes that suggest these viruses might spread more easily to and between people, and cause serious illness in people, or for changes that suggest reduced susceptibility to antivirals, as well as changes in the virus that might mean a new vaccine virus should be developed.

Diagnostics

CDC’s diagnostic tools that are used to detect seasonal influenza viruses also can detect novel influenza A viruses including A(H5N1) viruses. These diagnostic tools are used at more than 100 public health laboratories in all 50 U.S. states and have been shared internationally as well.

Vaccines

As part of pandemic preparedness activities and as a WHO Collaborating Center, CDC regularly develops candidate vaccine viruses (CVVs)—viruses made for production of vaccine—for novel bird flu viruses with pandemic potential. Two existing HPAI A(H5N1) candidate vaccine viruses are already available to manufacturers, and which could be used to make vaccine if needed.

The virus is also very closely related to two existing A(H5N1) candidate vaccine viruses that are already available to manufacturers, and which could be used to make vaccine if needed.

Antivirals

There are four commercially available FDA-approved prescription antiviral treatment drugs recommended for influenza. CDC’s preliminary genetic analysis suggests that currently available FDA-approved antiviral treatments for seasonal flu would work against these viruses. There are no markers known to be associated with influenza antiviral resistance found in the virus sequences from the patient’s specimen.

In addition to conducting laboratory studies and active surveillance, CDC also is engaging public health partner organizations to share information and ensure preparedness for any potential human infections.