Q&A: Bird flu threat still low after health care exposures, experts say
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Key takeaways:
- Although several exposed health care workers reported symptoms, just one person in Missouri is confirmed to have had bird flu.
- The threat to the general public remains low, experts say.
The threat from bird flu remains low for the general public, the CDC reiterated last week in an update related to a human case in Missouri with no exposure to infected animals.
Dozens of health care workers were exposed to the patient, and some later developed respiratory symptoms.
“To date, only one case of influenza A(H5N1) has been detected in Missouri,” the CDC said in its update. “No contacts of that case have tested positive for influenza A(H5N1).”
The patient was hospitalized in early September for other underlying medical conditions and tested positive for H5N1 despite not having contact with birds or cows, which have been at the center of the outbreak in the United States.
Among 18 health care workers in Missouri exposed to the patient before droplet precautions were instituted, two went on to develop mild respiratory symptoms, the CDC reported. One tested negative for the virus via PCR, and the other provided a blood sample for antibody testing.
Four other workers developed mild symptoms, including one who provided blood to test for H5 antibodies. Unlike the one health care worker who tested negative, none of the other five workers with symptoms underwent PCR testing, which “would have been unreliable at the time of discovery of these individuals' prior symptoms,” the CDC said. Three of those workers were among a group of 94 who were exposed to the patient after droplet precautions were put in place.
Nationally, there have been 14 reported human cases in the outbreak, 13 of which have been linked to contact with the nearly 101 million poultry, wild birds and backyard flocks or 243 dairy herds estimated to have been affected by the outbreak, according to the CDC.
Although there have been only a handful of cases in humans, the CDC and WHO have invested in speeding development of human vaccines against avian influenza.
We checked in with Andrew Pekosz, PhD, professor and vice chair of the department of molecular microbiology and immunology at the Johns Hopkins University Bloomberg School of Public Health, to get his thoughts on the Missouri case and the ongoing outbreak.
Healio: Does the Missouri situation alarm you?
Pekosz: Any suggestion that there may be person-to-person transmission of H5N1 is very concerning and needs to be investigated carefully. It is possible that the cases under investigation were infected with some other respiratory pathogen — which was the case with one of the health care workers who came down with symptoms. It’s somewhat reassuring that there are no cases of secondary transmission reported so far — meaning that none of the six health care workers under investigation reported any of their contacts coming down with respiratory symptoms around the same time.
Healio: What do you think public health and other officials should be doing or advising that has not happened?
Pekosz: It would be great if the CDC could confirm that there are no reports of respiratory illness in contacts of the six people under investigation. I assume there haven’t been but confirming that would be reassuring.
Healio: Do you agree with the CDC that the risk to the general public remains low?
Pekosz: Yes.
Healio: What level of concern should clinicians and the general public have about bird flu?
Pekosz: Clinicians should be aware of people with respiratory symptoms who have contact with dairy cows or dead animals and be sure to collect nasal swabs for testing. That nasal swab is an important sample and is often not collected unless the clinician thinks it’s particularly important to diagnose an infection. There is no need for the general public to have increased concerns about H5N1 at this time.
References:
- CDC. Avian influenza (bird flu): CDC A(H5N1) bird flu response update September 27, 2024. https://www.cdc.gov/bird-flu/spotlights/h5n1-response-09272024.html. Updated Sept. 27, 2024. Accessed Oct. 3, 2024.
- CDC. Avian influenza (bird flu): H5 bird flu: Current situation. https://www.cdc.gov/bird-flu/situation-summary/index.html. Updated Oct. 2, 2024. Accessed Oct. 3, 2024.
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