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The Centers for Disease Control and Prevention has undergone extensive changes under the second Trump administration that experts say may leave us more vulnerable to outbreaks.(Image credit: The Washington Post / Contributor via Getty Images)Share this article 1Join the conversationFollow usAdd us as a preferred source on GoogleSubscribe to our newsletter
When a cluster of hantavirus infections occurred on the cruise ship MV Hondius, approximately two dozen American travelers were aboard. At least seven disembarked before health authorities were alerted to the outbreak and returned home to the United States; 17 others remained on the vessel for several weeks and have only recently been repatriated. Concurrently, a few Americans who had no prior connection to the ship might have been exposed to the virus during an international flight.
Officials from the World Health Organization (WHO) state they have maintained consistent contact with the U.S. Centers for Disease Control and Prevention (CDC), coordinating strategies for the American passengers and exchanging technical details regarding hantaviruses. However, this is an atypical period for the CDC, and the agency is not behaving as it typically would during such outbreaks, Jodie Guest, senior vice chair of epidemiology at Emory University’s Rollins School of Public Health, informed Live Science.
Live Science engaged in a discussion with Guest — who previously headed Emory’s COVID-19 Outbreak Response Team in Georgia and advised Atlanta city officials during the mpox outbreak — regarding the nation’s handling of this epidemic. We explored whether the CDC, once regarded as the world’s leading public health institution, might no longer be adequately prepared to address infectious disease outbreaks.
Nicoletta Lanese: What distinguishes the CDC’s current response to this outbreak from its approaches in past ones?
Jodie Guest: I certainly feel the CDC’s response is less prominent than we would typically expect. The CDC usually assumes a leading role and is deeply involved in the initial investigation, as well as decisions regarding population movement, etc., and WHO assumed the primary responsibility in the CDC’s absence.
NL: WHO officials have indicated communication with CDC leadership. Is the level of communication lower than anticipated?
JG: I cannot comment on the specifics of their communications, but I can state that several weeks into this outbreak, the CDC had yet to issue any announcement. Furthermore, it was only this past Friday [May 8] that they disseminated a health alert through the HAN, the Health Alert Network, to medical practitioners in the United States. [The HAN is the CDC’s primary channel for transmitting urgent, time-sensitive public health information to officials, physicians, and laboratories.]
While it is unusual for such a health alert not to have been dispatched much earlier, I must acknowledge that the risk to the general populace is exceedingly low [in this specific situation]. That HAN notification is crucial as a procedural step, but simultaneously, we do not anticipate clinicians encountering individuals with hantavirus who are not already under observation.
The virus’s low transmission rate is certainly working to our advantage in this regard.
NL: What do you attribute to the CDC’s delayed reaction?
JG: I believe one factor is our withdrawal from the WHO. Consequently, when the U.S. departed the WHO in January, it significantly altered our relationship, impacting our presence at the decision-making table and our involvement in shaping protocols, surveillance, and so forth.
I do think CDC personnel were present during the final disembarkation [on May 10 in the Canary Islands]. However, typically, we would observe the CDC spearheading the disembarkation process, dictating destinations, managing patient transfers, and overseeing the comprehensive international protocols.
There have undoubtedly been substantial workforce reductions at the CDC, along with a degree of flux in the workforce [involving dismissals and rehirings]. Therefore, some individuals have not maintained consistent employment; some have been reinstated. Nevertheless, there are generally approximately 18% fewer CDC employees than previously recorded, encompassing outbreak investigators and specialists in areas such as cruise ship sanitation and port health.
Membership in the WHO grants access to early warning notifications prior to their public release.
Jodie Guest, senior vice chair of epidemiology at Emory University’s Rollins School of Public Health
NL: Reflecting on previous outbreaks, is there a relevant comparison to be made with the current situation? For instance, were the Ebola cases in 2014 a suitable comparison?
JG: I do believe Ebola serves as perhaps the most apt comparison. While there are numerous distinctions between the two diseases, from a response model perspective, the CDC’s stance during Ebola involved substantial global leadership. In the current hantavirus situation, I would characterize the international leadership as constrained, primarily focusing on domestic monitoring — which is critically important; I want to emphasize that.
Therefore, I perceive it as a reduction in visibility and influence, rather than leading a global response.
NL: Considering the U.S. is adopting a less prominent role, do you think this has impeded the WHO’s response in any way?
JD: I believe there was some initial sluggishness, and I attribute this not to any specific factor other than hantavirus not being what one would typically expect on a cruise ship. You see, the initial case was not tested for hantavirus; testing for hantavirus is not common practice and is not universally available. It is not a standard clinical assay. With all these elements combined, regardless of who was leading the effort, it was bound to cause delays. It would not be among the top diagnostic considerations.
However, I do believe there was an additional lag that occurred, which the CDC might have been able to mitigate. This is a hypothetical scenario, so we will never know for certain. But I also firmly believe that the WHO’s efforts in surveillance and their consistent communication have been exemplary. They have been exceptionally transparent about the unfolding events and have done a commendable job taking the lead in this situation.
NL: In the immediate timeframe, do you feel the current sluggishness from the CDC puts Americans at risk? Or is this more of a long-term concern?
JG: I believe we are facing a problem with our response model. However, at this juncture, I would not state that this has had any impact on the actual disease risk, including the care provided to the passengers who were on that ship. That is indeed the positive news. The immediate consequence of these changes on the disease burden is actually quite minimal.
Jodie Guest is an infectious disease epidemiologist at Emory University’s Rollins School of Public Health.
(Image credit: Courtesy of Emory University)
It pertains more to the visibility of our response and the strategic initiatives for future events, which is the primary concern. My greatest apprehensions relate to our preparedness during periods without active outbreaks. Our systematic approach to identifying early signs of anomalies — we must ensure a fully staffed and capable team is involved, working collaboratively with international leadership, all pursuing the same objective. Our surveillance systems are fundamental to the well-being of our populace.
From a broader perspective, I would assert that we are currently less equipped to handle contagious pathogens and epidemics than we typically would be. This is partly due to our withdrawal from the WHO and our diminished role in crucial discussions, now receiving information through secondary channels.
NL: In contrast to our past relationship with the WHO, what are we currently missing?
JG: Being a member of the WHO provides access to early warning notifications before they are made public. When you are not a member, there is no guarantee of such access. You forfeit access to immediate, real-time surveillance and contact tracing data that would have been available as a member.
It also signifies exclusion from the leadership in developing strategies, thus preventing participation in discussions concerning crucial decisions like how to manage disembarkations from cruise ships. We no longer have scientists embedded within WHO-led teams that handle virus sequencing, field investigations, and similar critical activities.
By no means do I suggest the WHO is deliberately withholding information from the CDC. That is not the intended message — however, WHO membership is vital. It is essential for thought leadership, as well as for the speed and depth of information dissemination and its flow.
Spanish Prime Minister Pedro Sánchez (left) and WHO Director-General Tedros Adhanom Ghebreyesus (right) speak at a media conference on May 12, 2026, in Madrid. The U.S. CDC would historically hold a greater leadership role during outbreaks, but it has stepped back from that role since exiting the WHO.
(Image credit: Carlos Lujan/Europa Press via Getty Images)
NL: Are there specific pathogens you are particularly concerned about concerning future epidemics?
JG: I do not have any specific ones to name — you know, I would not have predicted hantavirus for 2026. Therefore, I would refrain from compiling a list, but I would point out that we are experiencing an increase in the frequency of outbreaks like this, given our close proximity to one another, the declining vaccination rates for certain illnesses, and our global travel patterns. These factors are exceptionally significant to consider, alongside climate change.
NL: Do you believe the CDC could quickly regain its capabilities with sufficient investment, or would rebuilding it be a lengthy process?
JG: I am hopeful it will be a swift process. There are exceptional scientists still employed at the CDC, who are the absolute best in their field for this type of work. My concern is that restoring something that has been dismantled takes more time than maintaining it.
I also have two further concerns. We have experienced the departure of significant leadership and numerous highly qualified experts from the CDC, influenced by the current environment. This is regrettable, losing key thought leaders. Furthermore, this impacts the pipeline of new professionals entering public health — this is precisely the moment when we need everyone in public health to join us, yet we are hearing considerable apprehension from students: “Will there be a viable career path for me in this field?” The answer is unequivocally yes, but we must demonstrate that to them.
In a period characterized by reduced investment in the public health infrastructure within the United States, one can comprehend the basis for their inquiries.
NL: I assume this concern also extends to international students pursuing training in the U.S.?
JG: Absolutely. When we create obstacles to education and collaboration with other public health professionals, we are acting contrary to established best practices. Public health is a collaborative scientific endeavor. We must all work together to advance the health of everyone. We cannot focus solely on one specific area without acknowledging that the health of individuals globally impacts us all.
NL: Leaders frequently emphasize in the current outbreak that “this is not COVID.” Could you compare the two viruses?
JD: There are a couple of significant distinctions between the two: Firstly, hantavirus is a recognized virus. We possess prior experience with it. It is also an uncommon virus. COVID was a novel virus [SARS-CoV-2] that we were learning about in real-time, publicly. It also ceased being rare once it emerged; COVID is highly transmissible from person to person.
What we term the R0 [pronounced R-naught], which represents the reproductive number, is very high for COVID. It is quite low for hantavirus. A single infected individual with the Andes strain [the type of hantavirus implicated in the cruise outbreak] will infect approximately 1.19 additional people. Thus, the transmission rate is exceptionally slow, which is advantageous.
[In a previous outbreak, the median R0 across the entire epidemic was 1.19, while it was approximately 2.1 at the outset and 0.96 after control measures were implemented.]
The mortality rate of COVID, particularly in its early stages, was regrettably high, but it never reached the fatality rate observed with hantavirus.
Another point of comparison with COVID is that, due to the limited number of hantavirus cases, we do not need to be concerned about mutations in the same way we were with COVID. The more individuals affected, the greater the virus’s potential to mutate, and we simply do not have sufficient hantavirus cases to warrant concern about viral instability and mutation.
NL: During a past outbreak in Argentina involving transmission at a birthday celebration, the R0 for the Andes virus was estimated to be higher. What accounts for this difference?
JD: The more general R0 [of 1.19] is an average calculated across our typical, albeit infrequent, outbreaks of the Andes virus. The instance at the birthday party in Argentina exhibited a somewhat higher R0 due to the close proximity of individuals in that specific setting. It is uncommon to encounter an outbreak like this, where multiple individuals experience such a degree of close interaction.
I believe this is also the role the cruise ship has played in this particular outbreak. Again, cruise ships are not environments typically associated with hantavirus, but given its emergence on a cruise ship, it created a contained setting where, particularly given the weather conditions, people were not spending extensive time outdoors. Consequently, they were indoors, in close proximity, leading to more individuals becoming close contacts than we would ordinarily anticipate.
Public health experts did not anticipate a hantavirus case cluster linked to a cruise.
(Image credit: Getty Images)
NL: Regarding the Andes virus, what level of interaction is considered concerning? And how is “close contact” defined?
JD: For hantavirus, it appears that during approximately a 24-hour period around the onset of symptoms, an individual harbors enough of the virus to transmit it to another person. This represents a relatively brief window.
However, “close contact” in prior hantavirus outbreaks and the current one seems to involve situations like sharing sleeping quarters with someone, having meals together for extended durations in a confined space rather than the entirety of a cruise ship, for instance, [or] being a healthcare professional attending to a patient during that specific timeframe. Thus, it pertains to prolonged shared time during the period when transmission to another individual is most probable.
NL: Would “prolonged” imply a duration of several hours?
JG: I am uncertain if we have a more precise definition in terms of hours. When we consider an individual sharing a bedroom with another person, they spend many hours together, but it does not necessarily equate to eight hours.
In the Argentine outbreak linked to a birthday party, the duration of attendees’ presence in the room was documented, and there was even tracking of individuals’ seating arrangements at tables during meal consumption, which is another effective method of transmission if it is a respiratory illness and the room is enclosed. [The index patient in that particular instance was reportedly at the event for 90 minutes and experienced a fever.]
All these elements contribute to close contact. Close contact outdoors is fundamentally different from close contact indoors.
NL: How can we be confident that asymptomatic spread is not a likely scenario?
JG: We have not observed any human-to-human transmission originating from an asymptomatic individual. Therefore, as long as individuals remain asymptomatic, their likelihood of transmitting the virus to another person appears extremely low, if not non-existent.
This is what we refer to as basic surveillance, or “shoe-leather” epidemiology. It involves tracing all cases [during outbreaks]. To circle back to the HAN, this is one of the reasons why issuing a health alert is important; while we do not anticipate cases unrelated to the cruise ship, we would need to be aware if any arise.
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Consequently, the monitoring process tracks each individual who had contact and then categorizes the type of contact. Conducting this monitoring during the asymptomatic phase, as well as if and when symptoms develop — it is this tracking during the asymptomatic period that bolsters our confidence that we have not witnessed any transmission.
NL: So, in past outbreaks, has it always been traceable back to a symptomatic individual?
JG: Yes.
NL: Do you have any concluding remarks you would like to share?
JG: I would like to reiterate that, despite our somewhat noticeable absence from international efforts, this does not appear to have negatively affected the general health of Americans at this point in time. That is indeed the positive aspect.
Editor’s note: This interview has undergone minor edits for brevity and clarity. Live Science conducted this conversation with Jodie Guest on May 12, 2026; subsequent developments in the hantavirus outbreak may not be reflected.