The Threat of H5N1 Human to Human Transmission Grows: Possible Human H5N1 Cluster in Missouri.
The Threat of H5N1 Human to Human Transmission Grows: Possible Human H5N1 Cluster in Missouri.
How Public Health Agencies are Dropping the Ball.
In what could mark a critical turning point for public health in the U.S., Missouri is facing a potential cluster of H5N1 bird flu infections that may represent the first instances of human-to-human transmission of the virus in the country. Despite the alarming nature of this development, public health agencies at both the state and federal levels have been slow to respond. Delays in testing, contact tracing, and inconsistent communication have raised serious concerns about whether enough is being done to contain the spread of this deadly virus. The situation highlights the urgent need for reforms in how public health decisions are made and communicated, particularly as the world remains wary of another pandemic.
In a troubling development, a potential cluster of H5N1 bird flu infections in Missouri has grown to include eight individuals, marking what may be the first instances of person-to-person transmission of the virus in the United States. The Centers for Disease Control and Prevention (CDC) reported these findings on Friday, September 27, 2024. This development, if confirmed, could signify a critical shift in the virus’s ability to infect humans more easily, raising urgent questions about the response by both state and federal health agencies.
A Cluster of Infections: New Transmission Risks?
The H5N1 cases in Missouri began with a single patient in Jefferson City who was hospitalized on August 22, 2024, presenting with unusual symptoms and no known animal contact—a highly atypical situation for a virus that primarily spreads through direct exposure to infected birds. The patient has since potentially infected one household member and six healthcare workers, all of whom developed symptoms consistent with bird flu, according to the CDC. None of them were PCR tested because by the time the first case was identified as having H5N1, supposedly it was too late to test the others, who had recovered, with a PCR test. Two of the healthcare workers gave blood so the CDC could test to see if they have antibodies to H5N1. Those results are still pending. The CDC said that 94 healthcare workers were exposed to the patient in total, and unbelievably the CDC, nor the state or local public health agencies aren’t testing any of them for antibodies.
Historically, human cases of H5N1 have been rare and almost exclusively linked to direct contact with infected poultry. Clusters of human infections are even rarer, making this Missouri case particularly alarming if it turns out the others were infected with H5N1. If these cases represent sustained human-to-human transmission, it could suggest that the virus is evolving in ways that could pose a significant public health threat. There is a possibility that the other people were coincidentally infected with COVID around the same time but without a faster response and testing, it leaves us in the dark.
Missouri and CDC Response: Hesitation or Complacency?
Despite the potential severity of the situation, both Missouri state health authorities and the CDC have shown a marked reluctance to escalate their response. Initially, health officials did not aggressively test or trace the contacts of the infected patient, even though early identification of such clusters is critical for containment. The patient’s household contact, who developed symptoms simultaneously, was not mentioned in initial public briefings—an omission that delayed the public’s understanding of the true scope of the outbreak. As far as it is known, that household contact wasn’t tested either.
A CDC spokesperson later acknowledged this oversight but defended the agency’s risk assessment, stating that no evidence of widespread transmission had emerged. However, experts argue that this kind of delayed and incomplete information release undermines public health efforts and leaves communities vulnerable. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, criticized the piecemeal nature of the information, saying, “Without prompt and complete information, no risk assessment can be made. States need to be proactive with bird flu in cattle and humans, not reactive and evasive.”
Wastewater Data Adds to the Uncertainty
Adding to the confusion, Missouri's wastewater testing for influenza, including H5N1, for the week ending September 21, 2024, shows that the virus is present, but only as a small fraction of the total viral load. Yet, there are no clear details on whether testing sites near Jefferson City—the location of the initial patient—are included in the data. This lack of transparency further clouds the understanding of the potential spread of H5N1 in the state.
Missouri Wastewater Testing for Influenza for the Week Ending September 21, 2024
H5N1 is being detected, but it’s just the small dark sliver at the top of the circle. We don’t have clear data on where the wastewater testing data is coming from. We don’t know how many, if any, testing sites are in Jefferson City.
While wastewater surveillance can offer a broader picture of viral presence, without clear geographical data and an aggressive push for further testing, the extent of the outbreak remains uncertain.
Delays in Contact Tracing: A Missed Opportunity?
What stands out is the reluctance of public health officials to immediately launch widespread testing and contact tracing efforts among the patient’s contacts. According to the CDC, none of the initial contacts showed symptoms at first, prompting Missouri health officials to treat this case as an isolated incident. However, just one day after the CDC’s initial announcement, two additional symptomatic contacts were identified, further raising concerns that the virus may have been spreading undetected for days. On Friday, Sept. 27th, they acknowledged that 4 more healthcare workers exhibited symptoms similar to the other people.
Another concerning factor is the CDC’s timing when releasing critical information. It has become a recurring pattern for the agency to disclose potentially unpopular or alarming updates late on Fridays or over the weekend—periods when public attention is at its lowest. This tactic, which has been employed for at least the past five years, raises questions about transparency and the intent behind such timing. In the case of Missouri’s H5N1 cluster, this approach has only fueled frustration and mistrust, as key updates, like the confirmation of additional symptomatic healthcare workers, were delayed and downplayed, leaving the public and health professionals inadequately informed.
Despite the gravity of these findings, Missouri’s response has been slow and reactive rather than proactive. Health experts, including Adalja, have warned that aggressive testing of both symptomatic and asymptomatic contacts is crucial in such situations. “There needs to be more aggressive testing of contacts, both acutely and in convalescence,” Adalja emphasized, adding that the delay in information release is “not acceptable.”
CDC’s Changing Narrative and the Need for Leadership
In a press call on September 12, CDC Principal Deputy Director Nirav Shah downplayed the situation, stating that there was no evidence of further transmission. However, the narrative quickly changed the following day when two additional symptomatic contacts were disclosed. This flip-flop in communication has raised concerns about the CDC’s handling of the outbreak and the coordination between local, state, and federal agencies.
As the leading authority in infectious disease control, the CDC plays a pivotal role in managing potential outbreaks like this. However, its cautious approach, coupled with the reluctance of Missouri’s public health agencies to fully embrace aggressive testing and tracing protocols, is drawing criticism. Without decisive action and complete transparency, the public may be left in the dark, and the virus could gain a foothold before effective measures are implemented.
The Bigger Picture: What Does This Mean for Future Outbreaks?
The potential for H5N1 to acquire the ability to spread more easily among humans is a sobering reminder of the ongoing risk posed by zoonotic viruses. While the current cluster of cases in Missouri is concerning, it also reflects broader systemic challenges in how the U.S. handles emerging infectious diseases and the ongoing COVID pandemic.
The outbreak has already affected over 100 million poultry, 10,000 wild birds, and 239 dairy herds across 14 states, highlighting the scale of the threat. USDA reports that since April 2024, there have been A(H5) detections in 36 commercial flocks and 23 backyard flocks, for a total of 18.75 million birds affected.
Given the virus's high mortality rate in humans, even a slight increase in its ability to spread could have catastrophic consequences.
Moving forward, experts argue that the CDC must take a more assertive role in coordinating national response efforts. "Only the CDC, through forceful persuasion, can kickstart those vital processes in states that may otherwise want to avoid the bad news," said Adalja. Without a more unified and proactive response, the window of opportunity to contain the virus could close.
H5N1 Signs and Symptoms include:
fever (measured) or feeling feverish/chills
cough
sore throat
difficulty breathing (shortness of breath)
eye tearing; redness or irritation (conjunctivitis)
headaches
runny or stuffy nose
muscle or body aches
diarrhea/vomiting.
Note that these signs and symptoms are non-specific and overlap with those caused by other respiratory viruses, including COVID and seasonal influenza A and B viruses. Further evaluation of symptomatic people should be performed by the state or local public health agency to assess whether testing, isolation, and/or treatment is warranted.
Specimen collection should be initiated as soon as possible once indicated. Specimens should be tested at a laboratory using the CDC RT-PCR Influenza Assay to test for HPAI.” ”Testing and specimen collection guidance can be found at Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations”
TACT’s Overview: A Call for Action
The unfolding H5N1 cluster in Missouri should serve as a wake-up call for public health agencies. With the potential for human-to-human transmission, the time for a cautious, wait-and-see approach is over. Missouri state officials and the CDC must ramp up testing, contact tracing, and public communication to ensure the situation does not escalate further. Delays in these critical actions could result in the virus spreading unchecked, with devastating consequences.
This is a predictable and completely preventable situation, had the CDC and state public health agencies fulfilled their legal duties. Instead, we have corporate-bought politicians downplaying the risk and holding them back through their politically appointed public health agency directors, jeopardizing public safety.
We must urgently push for reform in the appointment process of public health agency directors to ensure they act in the best interest of public health, free from political and corporate influence. Current laws, meant to protect the most vulnerable—especially children—are effectively undermined by CDC guidance, allowing both government and businesses to evade accountability under the guise of public health recommendations.
The world has seen the catastrophic consequences of failing to act quickly during the COVID pandemic. This must not be repeated. The law requires a swift and decisive response to the spread of H5N1, and failure to act could result in a preventable public health crisis. Now is the time for legal and systemic change to prioritize the health and safety of the public above political or corporate interests.
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References:
1. CDC A(H5N1) Bird Flu Response Update September 27, 2024 https://www.cdc.gov/bird-flu/spotlights/h5n1-response-09272024.html
2. HPAI Confirmed Cases in Livestock, https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/hpai-confirmed-cases-livestock
3. “Bird flu casts a wider net as U.S. health officials keep drip-feeding information on Fridays” https://fortune.com/2024/09/26/bird-flu-us-health-officials-h5n1-cdc-information/
4. USDA: https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections
Looks like the CDC missed the confirmed H1N2 subtype from Michigan in their Pie chart of Influenza Positive Tests above.
Confirmed influenza A(H1N2)v virus infection:
https://www.cdc.gov/swine-flu/comm-resources/two-human-infection-swine-flu.html?CDC_AAref_Val=https://www.cdc.gov/flu/swineflu/spotlights/two-human-infection-swine-flu.htm
It will be interesting to see how the chart above evolves as we head into winter.
TACT...I wonder how a mismatched seasonal influenza vaccine would interact with H5N1 should this subtype undergo enhanced transmission? Unknowable, of course, but interesting to reflect on.