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Levine is co-founder and co-CEO of the US Business Action to End HIV.

Along with a 1 reported case in Massachusetts, the

New Hampshire Department of Health and Human Services (DHHS) has confirmed a person infected with eastern equine encephalitis (EEE) has died. The public health agency said the person was hospitalized due to severe central nervous system disease. The last reported human EEEV infection in New Hampshire was in 2014, when DHHS identified 3 human infections, including 2 fatalities. In the same statement, DHHS mentions there has been 1 confirmed case in Vermont this summer.

On August 16, the Massachusetts Department of Public Health (MDPH) released a statement discussing the confirmation of the first human case of EEE in the state this year. The confirmed case was discovered in an 80 year old man who was exposed to the vector borne disease in Worcester County. As a result, the risk level in the local communities of Douglas, Oxford, Sutton, and Webster has been raised to critical, and in Dudley, Northbridge, and Uxbridge the risk is increased to high.

Additionally, the neighboring communities of Auburn, Charlton, Grafton, Leicester, Mendon, Millbury, Millville, Southbridge, and Upton are now considered at moderate risk according to MDPH.

“This is the first time we have seen a person infected with EEE in Massachusetts since 2020,” Public Health Commissioner Robbie Goldstein, MD, PhD, said in a statement. “EEE is a rare but serious disease and a public health concern. We want to remind residents of the need to protect themselves from mosquito bites, especially in areas of the state where we are seeing EEE activity.

Though very rare, EEE is serious and a potentially fatal disease that can affect people of all ages. EEE is generally spread to humans through the bite of an infected mosquito. There were 12 human cases of EEE in Massachusetts in 2019 with 6 deaths, and 5 human cases with 1 death in 2020. There were no human cases of EEE in Massachusetts in 2021, 2022, or 2023.

EEE has a fatality rate of 33% to 70%, with most deaths occurring 2–10 days after the onset of symptoms.

In addition to a high mortality rate, long-term physical and mental complications, including permanent neurological deficits have been identified in many people who survive EEE.

Plymouth is approximately 40 miles south of Boston along the coast, and Worcester County is in the middle of the state, so the 2 areas are not in close proximity, but due to the elevated risk locally, the town of Plymouth decided to take action in response to outdoor parks. As of last Friday, all town public parks and fields are close daily from dusk until dawn.

“As Mass DPH has now elevated Plymouth’s EEE risk status to high, it is important to take extra precautions when outdoors and follow state and local health guidelines to avoid unnecessary risk to exposure to EEE. The health and safety of our community, residents, and visitors remain our priority,” Plymouth’s Commissioner of Health and Human Services, Michelle Bratti, said in a statement.

According to the Centers for Disease Control and Prevention (CDC) most people who are infected with the virus do not develop symptoms; however, for those that do, the date from the bite to the onset of the illness is 4 to 10 days. EEE can also result in fever or neurologic disease. The type of illness will depend on the age of the person and other factors. Those who are infected can develop meningitis.

There are no FDA-approved treatments for EEE and for patients who develop severe cases, they can be hospitalized to receive supportive treatment.

Over the weekend, MDPH detailed plans of spraying for mosquitos including aerially in areas of Plymouth County, and truck-mounted spraying in parts of Worcester County. As of Saturday, 10 communities in Massachusetts were raised to high or critical risk for EEE virus.

“The risk from EEE is high in parts of Plymouth County and critical in parts of Worcester County,” State Epidemiologist Catherine M. Brown, DVM, said in a statement. “In addition to recommending that people use mosquito repellent with an EPA-registered active ingredient and clothing to reduce exposed skin, we also recommend that evening outdoor events be rescheduled to avoid the hours between dusk and dawn. The mosquitoes most likely to spread EEE are most active during the dusk to dawn hours.”

There are preventative strategies to avoid EEE, and the MDPH has listed such measures 

For those who live in Massachusetts and want more information on EEE, it can be found 

 or by calling the DPH Division of Epidemiology at 617-983-6800.

1.NH DHHS Identifies Person Infected with Eastern Equine Encephalitis Virus in New Hampshire.The New Hampshire Department of Health and Human Services. August 27, 2024. Accessed August 28, 2024.
https://www.dhhs.nh.gov/news-and-media/nh-dhhs-identifies-person-infected-eastern-equine-encephalitis-virus-new-hampshire
2. State health officials announce season’s first human case of Eastern Equine Encephalitis in Massachusetts. MDPH. August 16, 2024. Accessed August 27, 2024.
https://www.mass.gov/news/state-health-officials-announce-seasons-first-human-case-of-eastern-equine-encephalitis-in-massachusetts
3.Plymouth to Close all Public Parks and Fields from Dusk to Dawn. Town of Plymouth. August 23, 2024. Accessed August 27, 2024. PDF.
4. Eastern Equine Encephalitis: Symptoms, Diagnosis, and Treatment. CDC. May 15, 2024. Accessed August 27, 2024.
https://www.cdc.gov/eastern-equine-encephalitis/symptoms-diagnosis-treatment/index.html
5. State officials announce plans to spray for mosquitoes in sections of Worcester and Plymouth counties due to EEE. MDPH. August 24, 2024. Accessed August 27, 2024. 
https://www.mass.gov/news/state-officials-announce-plans-to-spray-for-mosquitoes-in-sections-of-worcester-and-plymouth-counties-due-to-eee



The town of Plymouth decided to prohibit people from using the parks from dusk to dawn due to concerns over eastern equine encephalitis after a man contracted the rare disease in the state.

Concerns Over Mosquito-Borne Illness Causes Massachusetts Town to Create Curfew for Parks, Spraying in Counties

Multinational real-world analysis underscores the effectiveness of SOF/VEL across diverse populations and highlights the need for timely treatment initiation to improve patient outcomes.  You said: set up ama citation: 276 The SVR10K Hepatitis C study: final results show 98.9% SVR in 7,000 patients treated with SOF/VEL in Asia, Latin America, Middle East, Nordic and Southern Europe Soo Aleman, Ming-Lung Yu2, Fatima Higuera-de-la-Tijera3,Francisco Javier Garcia-Samaniego4, Marta Casado-Martin5, Grace Lai-Hung Wong6, Mario Álvares-da-Silva7, Joaquin Cabezas8,Miguel Castruita9, Oscar Beltran10, Mohammed Alzaabi11, Aastha Chandak12, Marta Martinez12, Artak Khachatryan12,Linda Chen13, Candido Hernández14, Kim Vanstraelen15, Yu Jun Wong16.  ChatGPT said:

Global Study Reports 98.9% SVR with SOF/VEL in Over 7,000 Hepatitis C Patients

A multinational real-world study of 7,027 patients treated with sofosbuvir/velpatasvir (SOF/VEL) for hepatitis C virus (HCV) infection reported a sustained virologic response (SVR) rate of 98.9%. "We're really excited to share this data at EASL this year," said Anu Oshinusi, MD, MPH, vice president of clinical research for hepatitis, respiratory, and emerging viruses at Gilead Sciences. "The study demonstrates that the high effectiveness of SOF/VEL in real-world populations aligns with previous findings, reinforcing the global applicability of current HCV treatment guidelines."

The study, conducted across Australia, Canada, Europe, and the US, found that SVR rates remained above 97% across all geographic regions, genotypes, and patient demographics, including those with coexisting conditions such as HIV or mental health disorders. "We’ve seen that these pan-genotypic direct-acting antiviral agents for hepatitis C have consistently shown high SVR rates across diverse populations," Oshinusi said. "These results emphasize the broader applicability of these treatments worldwide."

Patients in the study had a median age of 55 years (IQR 46–64), with 66% of patients aged 50 years or older. Males represented 65% of the cohort, and the study found that HIV/HCV coinfection was more common in males (5.8% vs 2.1%, p < .001), as was genotype 3 infection (35% vs 20%, p < .001), particularly in males aged ≥50 years. "The gender-related disparities in the prevalence of coinfection and genotype 3 infection are important considerations for developing more targeted treatment strategies," Oshinusi said.

While SVR rates remained high across both sexes and age groups, the study also examined the time to treatment initiation (TTI). "One important context to share is that the SVR 10k study wasn’t actually set up to analyze healthcare models. But it did look at time to hepatitis C treatment initiation, which showed clear improvements compared to past real-world data," Osinusi explained. "However, there is still room for improvement, as only 24% of the evaluated population initiated treatment with direct-acting antivirals within the first 30 days after their last positive RNA test. Some regions performed better than others in this regard."

The study revealed that females had a shorter median TTI compared to males. Among patients treated within the first month, 40% of females were treated compared to 25% of males (p < .001). "While it seems like the gender gap is reversing, more than half of patients in the study are still being treated more than six months after their diagnosis," Osinusi noted. "This demonstrates that there is still significant room for improvement in treatment initiation, particularly across all populations, regardless of gender."

SVR rates were consistently high across both males and females, including those with genotype 3 and cirrhosis. "Our data show that even in the presence of more challenging factors like genotype 3 and cirrhosis, SVR rates remained above 97%, which is a strong indicator of the effectiveness of these therapies," Osinusi added. "The key message here is that minimizing the time to treatment initiation will result in better outcomes for all patients, reducing the risk of severe liver complications and increasing treatment rates across the board."

In conclusion, the study highlights the importance of timely treatment for HCV, regardless of a patient's demographic or clinical profile. "The urgency to treat and minimize delays is crucial. Over time, it will result in fewer people having poor liver outcomes and will improve treatment rates for everyone infected with hepatitis C," Osinusi emphasized. These findings, coupled with the high SVR rates achieved globally, reaffirm the role of SOF/VEL as an effective treatment option and the importance of continuing efforts to optimize treatment initiation for all patients.

Aleman S, Yu ML, Higuera-de-la-Tijera F, et al. The SVR10K Hepatitis C study: final results show 98.9% SVR in 7,000 patients treated with SOF/VEL in Asia, Latin America, Middle East, Nordic and Southern Europe. Poster 276 presented at EASL 2025. May 7-10, 2025, New Amsterdam.

Multinational real-world analysis underscores the effectiveness of SOF/VEL across diverse populations and highlights the need for timely treatment initiation to improve patient outcomes.

Conferences

Therapeutic vaccines GS-2829 and GS-6779 demonstrate robust immune responses and strong safety profile in healthy participants, with potential to contribute to global hepatitis B elimination efforts.

Novel Hepatitis B Vaccines Show Promise in Phase 1a Study: Safety and Immunogenicity Results for GS-2829 and GS-6779

A Phase 1a study in New Zealand evaluated the safety, tolerability, and immunogenicity of two novel arenaviral vectored vaccines, GS-2829 and GS-6779, for hepatitis B virus (HBV) infection. The study enrolled 51 healthy participants, aged 33 on average, who received varying doses of the vaccines via intramuscular administration to assess safety and immune response. The results were presented at the 2025 International Liver Congress (EASL).

Safety results from the study showed that treatment-emergent adverse events (TEAEs) occurred in 98% of participants. Most of the adverse events were mild to moderate (Grade 1 or 2) and transient, including injection site reactions (55%), as well as flu-like symptoms such as headache (43%), fatigue (41%), and malaise (25%). Only one serious adverse event (SAE), a Lisfranc fracture caused by a road collision, was reported and was unrelated to the vaccine. Notably, no participants had to discontinue the vaccine, and there were no deaths, indicating that the vaccines were well tolerated by the participants.

The study also evaluated the immunogenicity of the vaccines. The results revealed that both GS-2829 and GS-6779 elicited dose-dependent immune responses. Participants demonstrated robust HBV-specific T cell responses to all encoded HBV antigens and produced high levels of anti-HBsAg antibodies that were durable over time. In cohort C8, where participants received additional doses (5 and 6), the magnitude of T cell responses was significantly enhanced, suggesting that repeated dosing could further improve immune responses. These findings indicate that both vaccines have the potential to generate strong and sustained immunity against HBV.

“We knew we had to induce robust T cell responses in addition to B cell responses,” said Anu Osinusi, MD, MPH, vice president of clinical research at Gilead Sciences. “This is different from your typical prophylactic vaccines. By including multiple well-conserved hepatitis B antigens and allowing for repeated dosing, we’ve been able to maximize the immune response.” Osinusi further emphasized that the design of the vaccines prevents the development of anti-vector neutralizing antibodies, ensuring that subsequent doses remain effective.

The encouraging safety and immunogenicity data presented in this Phase 1a study lay the groundwork for further investigation of GS-2829 and GS-6779 in individuals with chronic hepatitis B. As Oshinusi explained, “We are hoping to show data in patients with virally suppressed chronic hepatitis B in the near future, as part of the Phase 1b portion of this study.” The ultimate goal is to develop a vaccine that, in combination with other agents, could help achieve a functional cure for HBV. A functional cure would mean that after completing therapy, patients could control their chronic HBV infection without the need for ongoing treatment.

From a public health perspective, a successful therapeutic HBV vaccine could be transformative, especially in high-burden, resource-limited settings. “This vaccine could eliminate the need for lifelong antiviral therapy, reduce stigma, and alleviate concerns about transmission,” said Osinusi. The WHO has set a target to eliminate viral hepatitis as a public health threat by 2030, and Osinusi sees a therapeutic HBV vaccine as a key component in achieving that goal.

“We’ve made great strides in managing hepatitis C and turning hepatitis B into a manageable condition,” she added. “A therapeutic hepatitis B vaccine, combined with other agents, could significantly reduce the burden of liver disease, particularly in areas where lifelong antiviral therapy isn’t always accessible.” The findings from this study suggest that GS-2829 and GS-6779 could be an important part of global efforts to eliminate hepatitis B.

Gane EJ, Tedesco D, Abramov F, et al. Safety, tolerability and immunogenicity of GS-2829 and GS-6779, a novel arenaviral vectored therapeutic hepatitis B vaccine: results from a phase 1a study in healthy participants. Poster THU-246 presented at: The International Liver Congress 2025; May 7-10, 2025; Amsterdam, Netherlands.

Therapeutic vaccines GS-2829 and GS-6779 demonstrate immune responses and strong safety profile, showing potential to contribute to global hepatitis B elimination efforts.

Atea Pharmaceuticals is going to provide its full phase 2 data, which will show it met its primary endpoints at the upcoming EASL Congress in May. It will present the data in a poster titled, Efficacy and Safety of Bemnifosbuvir and Ruzasvir after 8 Weeks of Treatment in Patients with Chronic Hepatitis C Virus (HCV) Infection.

“Following our successful phase 2 study and the recent initiation of our global phase 3 program, we look forward to delivering the regimen of bemnifosbuvir and ruzasvir which we believe has the potential to increase the number of HCV patients that are treated and cured,” Atea CEO Jean-Pierre Sommadossi, PhD, said in a statement. “Untreated chronic HCV can have a profound impact on patients’ lives, as well as the associated healthcare and hospitalization costs, as the disease progresses in some cases to liver cancer.”

Earlier this month, the company announced it had dosed its first patient. It’s C-BEYOND trial will be conducted in the US and Canada, the company is concurrently conducting its C-FORWARD, an international trial. Each trial will enroll approximately 880 treatment-naïve patients, including those with and without compensated cirrhosis.

The regimen of bemnifosbuvir and ruzasvir will be administered orally once-daily for 8 weeks (in patients without cirrhosis) or 12 weeks (in patients with compensated cirrhosis) while the regimen of sofosbuvir and velpatasvir will be administered orally once-daily for 12 weeks for all patients with or without compensated cirrhosis.

The primary endpoint for each trial is HCV RNA < lower limit of quantitation (LLOQ) at 24 weeks from the start of treatment and encompasses sustained virologic response 12 weeks post-treatment (SVR12) in each arm. Measurement at 24 weeks from the start of treatment is to ensure the primary endpoint occurs at the same relative timepoint from the start of treatment in all patients. While C-BEYOND and C-FORWARD are both open-label trials, Atea has put measures and processes in place that are designed to blind Atea personnel to patient treatment assignments.

At last year’s The Liver Meeting, Atea presented a poster that demonstrated the combination therapy achieved a 97% sustained virologic response at 12 weeks post-treatment (SVR12) in a phase 2 lead-in cohort. According to the investigators, the analysis supported a short 8-week treatment with bemnifosbuvir and ruzasvir for chronic HCV.

The modeling results provided insight on the mechanism of action and demonstrated that the combination of bemnifosbuvir and ruzasvir was highly effective in blocking both viral replication and viral assembly/secretion in HCV-infected patients, independent of genotype, age, sex, or fibrosis score.

 studies to be approximately 10-fold more active than sofosbuvir (SOF), against a panel of laboratory strains and clinical isolates of HCV GT 1–5. 

 studies have also demonstrated bemnifosbuvir remained fully active against SOF resistance-associated substitutions (S282T), with up to 58-fold more potency than SOF.

The pharmacokinetic (PK) profile of bemnifosbuvir supports once-daily dosing for the treatment of HCV. Bemnifosbuvir has been shown to have a low risk for drug-drug interactions. Bemnifosbuvir has been administered to over 2,200 subjects and has been well-tolerated at doses up to 550 mg for durations up to 12 weeks in healthy subjects and patients.

The other half of the combination, ruzasvir, has demonstrated highly potent and pan-genotypic antiviral activity in preclinical (picomolar range) and clinical studies. Ruzasvir has been administered to over 1,500 HCV-infected patients at daily doses of up to 180 mg for 12 weeks and has demonstrated a favorable safety profile. The PK profile of ruzasvir supports once-daily dosing.



References
1.Atea Pharmaceuticals to Present New Data Showcasing Potential Best-in-Class Regimen of Bemnifosbuvir and Ruzasvir for Treatment of Hepatitis C Virus at EASL Congress 2025. Atea Pharmaceuticals press release. April 23, 2025. Accessed April 24, 2025.
2. Atea Pharmaceuticals Announces Dosing of First Patient in C-BEYOND, Phase 3 Study Evaluating Regimen of Bemnifosbuvir and Ruzasvir for Treatment of Hepatitis C Virus. Atea Pharmaceuticals press release. April 9, 2025. Accessed April 9, 2025.
3. Ribeiro R. Multiscale Modeling of Lead-in Results from a Phase 2 Study of an 8-Week Combination Regimen of Bemnifosbuvir and Ruzasvir in Patients with Chronic Hepatitis C Virus Infection. Poster #1467 presented at The Liver Meeting. November 15-19, 2024. San Diego, CA



Atea Pharmaceuticals will present the full clinical study at the upcoming EASL Congress in May. 

HCV Combination Therapy Meets Phase 2 End Points, Will Present Data at Conference

Scientists have created the first transgenic nonhuman primate model susceptible to hepatitis B virus (HBV), potentially enabling preclinical testing of curative therapies. The study used PiggyBac transposon technology to insert a liver-specific human sodium-taurocholate cotransporting polypeptide (hNTCP) expression cassette into rhesus macaque embryos.

Two macaque offspring were born from surrogate mothers after zygote modification. Both express hNTCP in the liver. Hepatocytes isolated from the macaques were shown to be susceptible to HBV infection, confirming functional expression of the viral receptor.

HBV is limited by strict species specificity, which has slowed the development of immunocompetent animal models. Prior work showed that vector-mediated expression of hNTCP in macaques permits infection. This study expands on that approach by producing a transgenic model capable of persistent liver-specific expression.

The findings offer a new platform for testing curative therapies for HBV and studying host-virus interactions in a preclinical setting.

In an email Q&A, Ben Burwitz, PhD, associate professor at Oregon Health & Science University’s Oregon National Primate Research Center, discussed the significance of the new model, the advantages of germline hNTCP expression over vector-based methods, and the technical process behind creating the transgenic macaques. He also outlined how the model could support antiviral development while acknowledging its current limitations as a developing research tool.

Contagion: Can you explain the significance of creating a transgenic rhesus macaque model for HBV research, and how does it address the challenges of studying HBV in nonhuman primates?

“One of the major barriers to the study of curative HBV therapies is the lack of a translational, immunocompetent model of HBV infection. HBV has a narrow host range, infecting only humans and chimpanzees. Chimpanzee research was halted in 2012 by the NIH, and this left a huge gap in the field. Very early on we showed that rhesus macaque hepatocytes could be infected with HBV in vitro if you artificially expressed the HBV receptor on their surface. This was the first data showing that the only block to HBV infection in rhesus macaques was the viral entry step. From there, we created viral vectors (e.g., Ad5 and AAV) that expressed the HBV receptor and could be given to rhesus macaques in vivo. These animals became susceptible to HBV infection, which drove our desire to make transgenic rhesus macaques expressing the HBV receptor naturally from the germline.”

Contagion: What specific advantages does the liver-specific expression of the human NTCP receptor provide for studying HBV infection in this model, and how does it replicate the natural susceptibility of human hepatocytes?

 “Rhesus macaques expressing human NTCP (HBV receptor) from the germline have several advantages over creating HBV susceptible rhesus macaques through viral vectors:

2) Not all hepatocytes are transduced by viral vectors, limiting HBV spreading

3) The viral vector genomes and hNTCP expression can be lost during cell division. Therefore, an optimal rhesus macaque HBV model would have transgenic, hepatocyte-specific hNTCP expression to overcome these challenges.”

 “In terms of replicating the HBV susceptibility of human hepatocytes, all measures of HBV replication that we have looked at thus far in vitro in rhesus macaque hepatocytes expressing human NTCP look identical to human infection.”

Contagion: Could you expand on the methodology used in this study, particularly the use of PiggyBac transposon technology to create the transgenic macaques? What are the key steps involved in generating these animals?

 “PiggyBac is a transposon. Transposons, also known as ‘jumping genes’, were first discovered by Barbara McClintock in the 1940s while studying maize. There are two components of the system. First, the transposon is the genetic element that can be moved from one genomic location to another (in our case, moving human NTCP from a circular DNA template to the rhesus macaque genome). Second, there is an enzyme called a transposase that facilitates the moving of the transposon. Therefore, we needed to inject single-cell rhesus macaque embryos (called zygotes) with both our transposase and our transposon.”

 “To be honest, the genetic engineering components of the project were far more straightforward than the Assisted Reproductive Technologies components. The Assisted Reproductive Technologies core at the Oregon National Primate Research Center capitalizes on decades of rhesus macaque reproductive and developmental science (the repro division was the first and only division upon the opening of the Oregon National Primate Research Center) to finally bring to bear our ability to make transgenic rhesus macaques. This core is second to none at in vitro fertilization, microinjection of single cell embryos, and biopsies and cryopreservation of transgenic embryos. My lab does none of this, we were just along for the amazing ride and had a good idea on how to use the technology.”

Contagion: What implications do these transgenic macaques have for the development of HBV therapies, and how do you envision this model being used in future drug development and therapeutic testing?

 “There has been a successful HBV vaccine since the early 1980s, yet many parts of the world continue to have high rates of HBV transmission. The vast majority of people living with chronic HBV infection (i.e., an infection that their body was unable to clear naturally) were infected at the time of birth. Therefore, the most relevant way we can use our model is to study the critical aspects of vertical transmission (mother-to-child at birth) that lead to chronicity, as well as to study new drugs that can eliminate HBV from the liver at different times in life. Humans living with chronic HBV live for decades, and therefore we have a lot of time to study these models if we can show that they also maintain chronic HBV infection indefinitely.”

Contagion: Are there any challenges or limitations in using this model, and how might researchers overcome them as they move forward with HBV-related studies?

 “In the end, no matter what manipulations we make to rhesus macaques, they are still not natural carriers of HBV infection. Therefore, there may still be barriers to the use of this model that we cannot anticipate. For instance, there may be immune responses to HBV in rhesus macaques that are not present in humans, simply because HBV has co-evolved with humans for over 10,000 years. We are excited about our new model, but there is still (and always seems to be) a lot of work left ahead of us.”

This new transgenic rhesus macaque model is the first immunocompetent nonhuman primate system naturally susceptible to hepatitis B virus. While it still requires further validation, it provides a useful tool for studying chronic infection, vertical transmission, and testing potential curative therapies in a biologically relevant setting.

Rust LN, Wettengel JM, Biswas S, Ryu J, Piekarski N, Yusova S, Lutz SS, Naldiga S, Hinrichs BJ, Sullivan MN, Lo JO, Protzer U, Smedley JV, Sacha JB, Hanna CB, Bimber BN, Hennebold JD, Burwitz BJ. Liver-specific transgenic expression of human NTCP in rhesus macaques confers HBV susceptibility on primary hepatocytes. Proc Natl Acad Sci U S A. 2025 Feb 18;122(7):e2413771122. doi: 10.1073/pnas.2413771122. Epub 2025 Feb 12. PMID: 39937851; PMCID: PMC11848295

Q&A with Ben Burwitz, PhD, on the significance of the new hepatitis B virus (HBV)-susceptible primate model and its potential to advance hepatitis B research and therapeutic development.

New Transgenic Rhesus Macaque Model Paves Way for HBV Therapy Development

During a hepatitis E outbreak in 2022 in South Sudan at the Bentiu refugee camp, the Hecolin HEV vaccine was shown to be highly protective. The results were published in 

“In the primary analysis we estimated an unadjusted two-dose vaccine effectiveness of 67.8% (95% CI –28.6 to 91.9), and a 2-dose vaccine effectiveness of 84.0% (–2085 to 992) after adjustment for potential confounders,” the investigators wrote. “The bias indicator analysis suggested that test-negative cases might have been more likely to have been vaccinated than their matched community controls due to different health care seeking behaviors, potentially meaning underestimation of effectiveness estimates. The test-negative design, which uses facility-matched controls, led to an adjusted two-dose effectiveness of 89.4% (564 to 98.0).”

The camp was an environment that enabled outbreak conditions. “The Bentiu camp in South Sudan, home to more than 100,000 people who have been displaced due to civil war, is a regular victim of hepatitis E and other waterborne disease outbreaks, likely due to the poor sanitation conditions and frequent flooding,” study senior author Andrew Azman, PhD, epidemiologist, UNIGE-HUG Centre for Emerging Viral Diseases, Médecins Sans Frontières

, and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, said in a statement.

The investigators identified 859 patients with suspected HEV. Of this group, 201 met the eligibility criteria and 21 cases had laboratory confirmed hepatitis E. Among the confirmed cases, 10 (48%) were unvaccinated compared with 33 (27%) of 121 matched controls, between May 10 and Dec 30, 2022.

Along with its protection, the study confirmed the protection provided by 2 doses during an epidemic, and the reduction of the disease. ‘‘Our results combined with others helped lead to recent approval by WHO’s International Coordinating Group (ICG) on Vaccine Provision of a stockpile of hepatitis E vaccines for emergencies,” Azman said. “This stockpile has the potential to save many lives and we’re looking forward to seeing it in action. These results have also already contributed to the WHO recommendations on the use of a 2-dose schedule,”

Developed in China, the Hecolin vaccine was approved in the country in 2011. It is a recombinant protein-subunit hepatitis E vaccine (HEV239) developed by Xiamen Innovax Biotech Co. It is recommended for adults aged 16 and older, particularly those at high risk of HEV infection. The World Health Organization (WHO) has recommended using the Hecolin vaccine in disease outbreak settings.

According to the Centers for Disease Control and Prevention (CDC), hepatitis E (HEV) is more common in many parts of the world where sanitation is poor and people have limited access to clean drinking water.

It is more rare in the US, but it is a leading cause of acute viral hepatitis, particularly in Asia and Africa.

 Approximately 20 million people worldwide are infected annually with HEV, according to the WHO. The virus is especially dangerous for pregnant women and people with chronic illnesses, with a mortality rate of up to 10%-50%.

1.Nesbitt RC, Kinya Asilaza V, Alvarez C, et al. The effectiveness of two doses of recombinant hepatitis E vaccine in response to an outbreak in Bentiu, South Sudan: a case-control and bias indicator study. 

. 2025;25(5):537-547. doi:10.1016/S1473-3099(24)00657-1
2.Hepatitis E vaccination is effective in an epidemic. Eurkealert. January 14, 2025. Accessed April 30, 2025.


https://www.eurekalert.org/news-releases/1070407


3. Hecolin Hepatitis E Vaccine.Vax Before Travel. last reviewed Janaury 25, 2025. Accessed April 30, 2025. 
https://www.vax-before-travel.com/vaccines/hecolin-hepatitis-e-vaccine
4.Hepatitis E Basics. CDC. May 14, 2024. Accessed April 30, 2025. https://www.cdc.gov/hepatitis-e/about/index.html



The Hecolin hepatitis E virus vaccine was delivered with a reduced 2-dose schedule to people living in a refugee camp to try to reduce an outbreak.  

Steven Levine

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