Truth vs Fearporn: Marburg Virus
Should you be more afraid of the virus or of politicized public health and media?
Electron microscopic imaging of Marburg Virus, provided for the benefit of the virus deniers. Yes, Marburg Virus exists, has been isolated, has existed for millennia, and is highly lethal. Now that we have that cleared up, can we talk about whether or not this virus (which does exist) represents a significant threat to domestic US Citizens?
The dreaded Marburg Virus. A major infectious disease threat to the United States, or another grift that keeps on giving?
Promoted Narrative circa January 2025: You should be afraid, you should be very afraid. It is all Trump’s fault. There is a Marburg outbreak crisis in Tanzania! Soon it will jump across the Atlantic and begin indiscriminately killing Americans like a rabid wolf. The CDC is the only thing preventing this from happening, and Trump is politically interfering with the CDC doing it’s noble work in close cooperation with the WHO. The US Government needs to spend billions of dollars on vaccine and monoclonal antibody development/manufacturing RIGHT NOW to prevent the terrible thing from happening. This is only one example of how Trump and his policies are putting Americans at risk from widespread disease and death caused by scary viruses.
Variant of the Promoted Narrative: The former USSR was on the threshold of weaponizing aerosolized Marburg as a biowarfare agent according to a defector (Ken Alibeck). Kanatzhan “Kanat“ Baizakovich Alibekov (born 1950), known as Kenneth “Ken“ Alibek since 1992, is a Kazakh-American microbiologist, bioweaponeer, and biological warfare administrative management expert. He was the first deputy director of Biopreparat. During his career in Soviet bioweaponry development in the late 1970s and 1980s, Alibekov claims to have managed projects that included weaponizing glanders and Marburg hemorrhagic fever, and created Russia’s first tularemia bomb. He defected to the USA In 1992, and has since become an American citizen and made his living as a biodefense consultant, speaker, and entrepreneur. He had actively participated in the development of biodefense strategy for the U.S. government. I have met and spoken with him multiple times. Much or most of what he reported around the time of his defection has remained unverified, but billions of US dollars have been spent in an attempt to develop biodefense vaccines for the threat agents he reported. However, the USSR’s BW program was massive, employing over 50,000 people across dozens of facilities under Biopreparat and military oversight. Marburg was part of a “second-generation” effort using molecular genetics for enhanced pathogens, and there is a large body of evidence that the USSR’s BW program determined that Marburg supported aerosol delivery much better than Ebola did.
Facilities like Vector produced ton quantities of weaponized Marburg, favoring it over Ebola for its stability in aerosol form. By the late 1980s, Marburg was classified as a “strategic-operational” weapon alongside agents like anthrax, plague, and smallpox.
Post-Soviet inspections (e.g., by U.S./UK teams in 1993) at sites like Pokrov and Stepnogorsk revealed infrastructure for mass production, including bunkers for virus cultivation. Boris Yeltsin admitted the illegal program in 1992 and ordered its dismantlement, but remnants persisted into the 1990s.
There has been no credible evidence that Russia has advanced or deployed a Marburg virus-based biological weapon in Ukraine, despite obvious incentives to do so. Claims or discussions around Marburg in the context of the Russia-Ukraine conflict primarily stem from historical Soviet-era biological weapons programs, Russian accusations against Ukrainian/U.S. biolabs, and unrelated recent outbreaks elsewhere.
Alternative Narrative: Marburg virus has existed in Africa for millennia in various animal reservoirs. It seems to mostly be maintained in clusters of bats. Like many viral pathogens, when it does jump from it’s natural host into a human host, it is highly lethal. In the case of Marburg, so lethal that it quickly burns itself out. It is not spread by breathing or as an aerosol. Despite existing for thousands if not millions of years, there has never been a large, sustained Marburg virus outbreak. Circa January 2025, based on past outbreaks, the probability was very high that once again, the Marburg outbreak in Tanzania would be self limiting.
There is no reason to panic about Marburg. Like Measles, this has nothing to do with President Trump and his domestic or global health policies, the threat to the US homeland is tiny, there is no emergency, and there is no objective reason to rush out and issue billion dollar plus contracts to accelerate the clinical development and domestic US manufacturing of Marburg medical countermeasures. That said, there are a group of individuals and companies that would reap enormous financial benefits from promoting fear of Marburg. These include the federal agencies and their personnel that would manage additional contracts.
There is plenty of time to update the internal HHS/DHS threat assessment and threat determination documentation and plans based on the new Trump Administration global health security policy focus on protecting the homeland from offshore threats, while engaging in bilateral partnerships to support other nations solving their own infectious disease threats. These threat assessment and determination plans should be updated to reflect the general position that the USG will no longer considering itself responsible for protecting the world from infectious diseases, but instead will focus first on protecting the USA and then on assisting others as a partner and advisor when requested. There have been very substantial US investments in development of medical countermeasures for Marburg, in large part due to the reports of USSR weaponization. To date the many hundreds of millions to billions of dollars invested by the USG have yet to yield a robust, safe, effective protective or therapeutic countermeasure for Marburg Virus infection and disease.
In terms of the “Russian Threat”, despite the pressure of the Ukrainian conflict, there is no evidence that Russia is interested in reactivating it’s biowarfare programs, but there IS evidence of US biowarfare development activity (“incapacitating agents”). This risk scenario is best handled via enhanced biowarfare treaty and verification capabilities, much as exist for thermonuclear weapon program containment.
Suppose the USG were to abruptly ramp up Marburg Virus medical countermeasure development activities. In that case, it might even be destabilizing due to potential misinterpretation that the USG has itself developed a weaponized Marburg and feels the need to develop a countermeasure to proactively protect DOW, NATO, or allied forces/warfighters in the event of a planned deployment.
Trump’s actions could allow harmful viruses to enter US: Dr. Stephanie Psaki
According to Dr. Stephanie Psaki, the sister of ex-press secretary Jen Psaki, who worked for former President Joe Biden, Trump’s actions could allow harmful viruses like the Marburg virus, which is similar to Ebola and can kill up to 88 percent of those infected, to enter the United States, Daily Mail reported.
Tanzania is right now experiencing a Marburg outbreak, with the death of eight of the nine confirmed patients.
The only way to safeguard Americans against the virus, which triggers bleeding from orifices like the mouth, ears, and eyes, “is to stop it at its source,” stated Dr. Psaki, stressing that there is no vaccination or medical care for the virus.
The former health advisor to Biden stated in an editorial that CDC specialists should put efforts to combat the virus and coordinate with public health partners.
According to her, Trump’s suspension makes the US less ready to combat “unknown pathogens,” much like the outbreak of COVID-19. “As I’ve watched the Trump administration announce a series of actions that undermine our ability to detect and respond to biological threats... I wonder: Who is protecting the American people from Marburg right now?” she asked.
On January 11, the WHO alerted her team about the Marburg outbreak in Tanzania, citing “reliable reports from in-country sources” and reporting the death of five people.
Following this, her team completed a risk assessment and determined that there was a significant risk.
Dr. Stephanie Psaki PhD, MS is the sister of former WH (Biden) Press Sec. Jen Psaki. According to her Bio posted on the Johns Hopkins University Center for Strategic and International Studies:
She previously served as special assistant to the president and the inaugural U.S. coordinator for global health security at the White House, a role that included overseeing the federal government’s response to emerging global health threats such as mpox, Ebola, and Marburg. While on staff at the National Security Council, Psaki also coordinated U.S. government engagement on issues ranging from ending HIV/AIDS as a public health threat, investing in health workers, expanding access to sexual and reproductive health services, and protecting human rights.
Fast forward to the present.
Dr. Psaki and her dark winter warnings were wrong, and Marburg history has predictably repeated itself.
The outbreak was declared on January 20, with two confirmed cases reported from Kagera region. Both patients died from their infections. In a statement, health minister Jenista Mhagama urged the public to remain vigilant, continue taking precautions, and to report any unusual events.
In a statement today praising Tanzania’s swift response, the World Health Organization (WHO) said alongside the two confirmed cases there were eight probable cases, all fatal. The outbreak marked Tanzania’s second Marburg virus outbreak; the country’s first occurred in the same region in 2023.
The WHO said growing expertise in the African region has been crucial for mounting effective outbreak control strategies. The group added that it helped support Tanzania in its response by training more than 1,000 frontline health workers and delivering essential medical supplies and equipment.
Source still under investigation
Regarding the 100% case fatality rate, the WHO said in a separate overview that the high level was concerning but had been seen in earlier outbreaks. It added that the eight probable cases are a sign of late health-seeking behavior, which increases the risk of further transmission.
So far, the source of the outbreak still isn’t known, and the risk of re-emergence from a new spillover from the animal reservoir remains, the WHO said.
Marburg Virus Threat Assessment (as of October 23, 2025)
Historically, I have relied on painstaking literature searches and poking around on US Government websites (or classified documents) to perform threat assessments. Fortunately, SuperGrok now does a great job in minutes that used to take days. Here is the Grok assessment, which seems pretty reasonable and accurate to me as someone who used to do this kind of work for a living.
Marburg virus disease (MVD) is a rare but severe viral hemorrhagic fever caused by the Marburg virus, a member of the Filoviridae family (closely related to Ebola virus). It poses a significant public health threat due to its high fatality rate, potential for human-to-human transmission, and lack of approved vaccines or treatments. Below is a comprehensive assessment based on recent epidemiological data, outbreak history, transmission dynamics, and risk evaluations from authoritative sources like the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC). This focuses on the current global context, with no active large-scale outbreaks as of mid-2025, but ongoing vigilance is warranted due to zoonotic reservoirs in Africa.
Overview of Marburg Virus
Pathogen Characteristics: Marburg virus is an RNA virus naturally hosted by fruit bats (primarily Rousettus aegyptiacus). Initial human infections occur via prolonged exposure to bat colonies in mines, caves, or forests. Once in humans, it spreads through direct contact with infected bodily fluids (blood, vomit, feces, semen) or contaminated surfaces. It is not airborne but can spread via fomites in healthcare settings (nosocomial transmission).
Incubation Period: 2–21 days (average 5–10 days).
Symptoms: Sudden onset of fever, headache, muscle aches, followed by hemorrhagic manifestations (bleeding from orifices), rash, organ failure, and shock. Survivors may experience long-term complications like uveitis or neurological issues.
Case Fatality Rate (CFR): Historically 24–88%, averaging ~50% across outbreaks. Supportive care (e.g., fluids, electrolytes) improves outcomes, but no specific antivirals or vaccines are licensed (candidates like mAb114 and vesicular stomatitis virus-based vaccines are in Phase 2/3 trials).
Recent Outbreaks and Epidemiology
Marburg outbreaks are sporadic, mostly in sub-Saharan Africa, with 17 documented events since 1967 (total ~600 cases). Imported cases have occurred in Europe and the Americas via travel or lab accidents.
2025 Update: The Tanzania outbreak was the most recent major event, fully resolved by March. No new outbreaks reported in Africa or globally since then. However, a rare mutation was detected in Uganda (October 2025), increasing interhuman transmission potential; enhanced surveillance is underway. Ongoing training (e.g., WHO-UVRI partnership in Uganda) focuses on early detection of Marburg and Ebola.
Global Trends: Increasing frequency (4 outbreaks since 2017) due to mining/urban expansion into bat habitats. No U.S. cases in 2025.
Transmission and Contagion Risk
Zoonotic Spillover: High in endemic areas (e.g., Uganda, DRC, Angola); low elsewhere.
Human-to-Human: Requires close contact; R0 (reproduction number) ~1.5–2 (similar to Ebola but lower than measles). Sexual transmission possible up to 7 weeks post-recovery.
Factors Amplifying Spread: Poor healthcare infrastructure, burial practices, delayed reporting. In 2025 Tanzania, initial underreporting delayed response by 5 days.
Current Threat Level
Using WHO/CDC frameworks, risk is assessed across levels:
Emerging Concerns: The Uganda mutation (Oct 2025) raises propagation risks; mathematical models suggest vaccination could reduce CFR by 30–50% if deployed early. Climate change/habitat loss may increase bat-human contact.
Prevention and Response Strategies
Individual: Avoid bat-exposed areas; use PPE in high-risk jobs. Post-exposure: Monitor 21 days; semen testing for survivors.
Public Health: Contact tracing (21-day follow-up), safe burials, IPC in healthcare (e.g., CDC’s 2024 Rwanda training reached 100+ workers). Community education key to breaking chains.
Global Preparedness: WHO’s core protocols enable multi-outbreak vaccine trials. U.S. CDC deploys experts for IPC; no routine traveler screening advised.
Mitigation Gaps: No approved countermeasures; focus on “One Health” (bat surveillance, ecosystem protection).
Conclusion
As of October 2025, Marburg remains a high-impact, low-probability threat—lethal but containable with swift action, as demonstrated in Tanzania. Global risk is low outside Africa, but vigilance is essential amid mutations and environmental pressures. Enhanced surveillance, vaccine acceleration, and international cooperation (e.g., WHO-Africa CDC) are critical to prevent escalation. For travelers to endemic areas, CDC’s Level 1 advisory (usual precautions) applies. If new outbreaks emerge, early reporting and monitoring will be important.
Leading Medical Countermeasures
Monoclonal Antibodies
Mapp Biopharmaceutical, Inc. is a biopharmaceutical company founded in 2003 by Drs. Kevin Whaley and Larry Zeitlin, specializing in the development of novel pharmaceuticals for the prevention and treatment of infectious diseases, with a focus on unmet needs in global health and biodefense. The company is developing MBP091, a single human monoclonal antibody (mAb) therapeutic designed as a pan-Marburg virus medical countermeasure to treat hemorrhagic fevers caused by Marburg virus and the closely related Ravn virus. MBP091 was isolated from a survivor of Marburg virus infection in the laboratory of Dr. James Crowe at Vanderbilt University Medical Center and subsequently licensed by Mapp.
The development of MBP091 has been supported by significant funding from the Biomedical Advanced Research and Development Authority (BARDA), part of the U.S. Department of Health and Human Services. BARDA initially awarded a contract in 2019 for $16.5 million, with options for an additional $30.0 million, to advance MBP091 through Phase 1 clinical trials. BARDA has continued to extend its partnership with Mapp to further advance the development of MBP091, with the goal of creating the first licensed therapeutic specifically for Marburg virus disease (MVD). If successful, MBP091 would be the first therapy to specifically treat MARV infections, which are caused by a severe and often fatal viral hemorrhagic fever with an average case fatality rate of approximately 50%.
In March 2024, Mapp Biopharmaceutical entered into a collaboration with ProBioGen, a contract development and manufacturing organization (CDMO), to develop a cell line for an afucosylated antibody targeting Marburg virus infection. This collaboration leverages ProBioGen’s GlymaxX® technology to enhance the therapeutic potential of the antibody by adjusting its afucosylation levels, thereby improving its antibody-dependent cellular cytotoxicity (ADCC) and overall efficacy against the virus. The project has been funded in whole or in part with federal funds from the U.S. Department of Health and Human Services, BARDA, under contract number 75A50122C00076.
Vaccines
Recombinant Chimpanzee Adenovirus Vectored Vaccine
The Sabin Vaccine Institute is developing a recombinant chimpanzee adenovirus type 3 (cAd3)-vectored Marburg virus vaccine, which is based on a platform originally developed by Okairos Laboratories and later acquired by GSK. This vaccine candidate, known as cAd3-Marburg, uses a non-replicating chimpanzee adenovirus vector to deliver the Marburg virus glycoprotein (GP) antigen, aiming to induce a protective immune response. The vaccine has demonstrated safety and immunogenicity in Phase I clinical trials, with 95% of participants producing a glycoprotein-specific antibody response four weeks after a single vaccination, and 70% maintaining this response at 48 weeks.
Sabin is advancing the vaccine through Phase II clinical trials in multiple regions. A randomized, double-blind, placebo-controlled Phase II trial is ongoing in Uganda and Kenya, evaluating the vaccine’s safety, tolerability, and immunogenicity in healthy adults. Additionally, a Phase II trial has been initiated in the United States, enrolling 200 participants aged 18 to 70 across sites in Florida, Alabama, Illinois, and Texas.35 This U.S. trial is a double-blind, placebo-controlled study designed to assess safety and immunogenicity over a 12-month period.
In response to the 2024 Marburg virus outbreak in Rwanda, Sabin supported an open-label Phase II trial by supplying the investigational vaccine, with over 1,700 doses administered to frontline health workers within nine days of the outbreak declaration. This emergency response trial, sponsored by the Rwanda Biomedical Centre, provided critical real-world data on the vaccine’s deployment and safety profile. Data from this trial will be shared with Sabin to support the vaccine’s licensure process.
The development of this vaccine is supported by the Biomedical Advanced Research and Development Authority (BARDA), which has awarded Sabin approximately $252 million in contracts for research and development against Marburg and Sudan virus diseases. The Sabin Vaccine Institute continues to prioritize the advancement of this vaccine, emphasizing the urgent need for a preventive tool against Marburg virus disease, which has a case fatality rate ranging from 24% to 88%.
Amy Finan, the Chief Executive Officer (CEO) of the Sabin Vaccine Institute since April 2016, succeeding Ambassador Michael W. Marine. Prior to that, Dr. Peter Hotez had led the Sabin Institute. In her role, she has led the development and implementation of a new organizational strategy focused on making vaccines more accessible, enabling innovation, and expanding immunization globally. Under her leadership, the institute has rebuilt its vaccine research and development programs, notably launching a new R&D initiative in 2019 by securing a license from GSK to develop vaccines against the Ebola Sudan and Marburg viruses, which have since advanced to Phase 2 trials with over $250 million in U.S. government funding. She has also strengthened key partnerships with global health organizations such as the World Health Organization, Gavi, the Vaccine Alliance, UNICEF, the Bill & Melinda Gates Foundation, CEPI, and Wellcome Trust, while expanding the institute’s staff, Board of Trustees, and funding base.
I had personal experience dealing with the GSK team and their chimp adenoviral vectored Ebola vaccine back in the day. Bottom line- despite being treated by WHO as the golden child and having massive backing from GSK corporate, the product failed to meet the need at the time because it could not be manufactured at a sufficient scale.
Recombinant VSV-vectored Vaccine
The vesicular stomatitis virus (VSV)-based vaccine for Marburg virus (VSV-MARV) is a leading experimental vaccine candidate that uses a weakened form of VSV to deliver the Marburg virus glycoprotein (GP), thereby stimulating an immune response against Marburg virus. This vaccine platform has demonstrated high efficacy in nonhuman primates (NHPs), providing complete protection against lethal Marburg virus challenge with a single dose. Protection has been achieved even when the vaccine is administered as a post-exposure treatment, with 100% survival in animals vaccinated 20–30 minutes after challenge, 5 out of 6 animals protected when given 24 hours after infection, and 2 out of 6 protected when treatment started 48 hours post-infection.
The vaccine has shown rapid protective effects, with 100% survival in NHPs vaccinated 14 or 7 days before challenge and 75% survival when vaccinated just 3 days prior to challenge. This fast-acting potential makes it suitable for emergency outbreak situations. The protective mechanism is primarily humoral, driven by the induction of antigen-specific IgG antibodies and neutralizing antibodies, although a functional cellular immune response, including T cell activation and NK cell activity, is also observed. Transcriptomic analyses confirm that the vaccine activates B cells and antiviral defense pathways, with gene expression changes indicating a robust innate immune response that supports the development of protective immunity.
The vaccine has been tested with different doses, including low doses (1 × 10³ or 1 × 10⁵ plaque-forming units) administered 14 or 7 days before challenge, and still provided uniform protection with no detectable viremia, sustained IgG responses, and evidence of antibody-dependent cellular phagocytosis. The VSV-MARV vaccine is attenuated compared to wild-type VSV, showing no neurovirulence in NHPs, which supports its safety profile. Despite its strong preclinical results, there are currently no licensed vaccines or therapeutics available for Marburg virus disease, and the VSV-MARV vaccine remains under development for potential clinical use.