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Hecolin Hepatitis E Vaccine

Hecolin is a recombinant protein-subunit hepatitis E vaccine (HEV239) that contains the hepatitis E virus (HEV)-like particles prepared using a recombinant Escherichia coli expression system. Since 2011, the vaccine has been approved for use in China in people aged 16 and above and is recommended for individuals at high risk of HEV infection. Hecolin® was found well tolerated and has been demonstrated to be safe for adults. In 2015, the World Health Organization (WHO) recommended using Hecolin in disease outbreak settings.

The vaccine protects against symptomatic HEV infection with a very high efficacy rate. Data on this protection primarily applies to genotype 4 diseases; data on diseases caused by other genotypes are either too limited (genotype 1) or unavailable (genotype 2 and 3). The vaccine can effectively lower, but not eliminate, the risk of asymptomatic infection. The duration of follow-up in the available published reports has been up to nearly 2 years; some unpublished data for up to 4 years after completing immunization are available. Long-term efficacy beyond this time point, duration of protection, and the need and timing for booster dose remain to be determined.

On January 8, 2025, a phase 3 case-control clinical study conducted during an HEV outbreak in Bentiu (South Sudan) estimated the effectiveness of a two-dose regimen against HEV genotype 1 during a protracted outbreak, supporting its use in similar contexts. These findings indicate moderate to high two-dose vaccine effectiveness using several study designs and analytical methods.

Hecolin® was developed and manufactured by Xiamen Innovax Biotech Co., Ltd. in Xiamen, China.

Hecolin Hepatitis E Vaccine Indication

Hecolin is a vaccine that is indicated to prevent hepatitis E. In March 2024, the WHO strongly recommended that in specific settings, women of childbearing age, including those who are pregnant, should have access to Hecolin accompanied by relevant information on its benefit-risk profile. However, there is no data on its protection against severe forms of the disease, such as acute liver failure, which is particularly frequent in pregnant women. A study by Wasuwanich et al. in 2021 focused on hepatitis E-related hospitalizations in the United States between 2010 and 2017, noting an increase in hospitalization rates over that period.

Hecolin Hepatitis E Vaccine Dosage

Hecolin is administered intramuscularly into the deltoid muscle as a single injection on Days 1, 29, and 180. 

Hecolin Stockpile

Since 2015, the World Health Organization has recommended its use in outbreak settings. The WHO’s International Coordinating Group on Vaccine Provision maintains a stockpile of hepatitis E vaccines for emergencies. In the United States, hepatitis E is relatively underexplored, and vaccine development for this disease has not been a priority.

Hecolin Hepatitis E Vaccine News

January 14, 2025 - Iza Ciglenecki, Operational research coordinator at MSF Switzerland, stated, ‘‘Our study then compared the vaccination status of 201 patients testing positive for hepatitis E between May and December 2022 with those in their neighborhood presenting no symptoms. Despite fewer hepatitis E cases than expected after vaccination, our study revealed that two doses of vaccine were effective, an excellent result given the particular context of a camp for displaced people.’’

January 10, 2025 - A study published by The Lancet stated that the results of this study, combined with the existing evidence from clinical trials, suggest that a two-dose regimen of the Hecolin vaccine could be an effective and feasible strategy for controlling hepatitis E outbreaks. 

July 17, 2024 - The Lancet: Volume 12, Issue 11 - Hepatitis E vaccination: continued benefit for pregnant women in vulnerable settings.

July 26, 2019 - Human HEV includes four genotypes; the nonepidemic, zoonotic genotypes (typically 3 and 4) have gained increasing recognition in North America and Europe over the past decade because of the potential risk of transmission through food, blood transfusions, and organ donation. However, relatively little attention and few resources have been invested into genotypes 1 and 2 (g1/g2), which cause outbreaks among the world’s most vulnerable populations living or access to safe water and sanitation infrastructure. 

May 2, 2019—On May 1, the first U.S. participants in the clinical trial of Hecolin were vaccinated. This is the first time the FDA has approved a Chinese vaccine for a clinical trial in the U.S. The trial will be carried out in three phases. Phase 1 is scheduled to enroll 25 U.S. volunteers, and Phases 2 and 3 are FDA-approved vaccine trials expected to be conducted in a third country.

Hecolin Hepatitis E Vaccine Clinical Trial

Clinical Trial NCT03827395: Safety Study of Hepatitis E Vaccine (HEV239) in Healthy U.S. Adult Population. This is a Phase I double-blind, randomized, placebo-controlled trial (1:4 ratio of placebo to vaccine) of Hepatitis E virus vaccine containing a 239 amino acid subfragment of Hecolin(R) (HEV-239) in 25 U.S. males and non-pregnant females ages 18 - 45 (inclusive) to assess the safety, reactogenicity, and immunogenicity of Hecolin  (HEV-239).

The main adverse events associated with its use have been local reactions at the injection site. Current evidence demonstrates that this vaccine is highly immunogenic, with nearly all the recipients seroconverting after three doses administered in a 0, 1, and 6-month schedule. Limited data show that even two doses (at 0 and 6 months, or 0 and 1 month) lead to a high rate of seroconversion through the antibody titers are lower.

mRNA-1893 Zika Vaccine

Moderna's mRNA-1893 vaccine candidate contains an mRNA sequence encoding for the structural proteins of the Zika virus. It is designed to cause cells to secrete virus-like particles, mimicking the cell's response after a natural infection. Preclinical data published in the Journal of Infectious Diseases have shown that vaccination with mRNA-1893 protected mice against Zika virus transmission during pregnancy.

On August 19, 2019, Moderna, Inc. announced that the U.S. Food and Drug Administration (FDA) had granted Fast Track Designation for its investigational mRNA-189. It is currently being evaluated in a Phase 1 study to prevent Zika virus infection in healthy adults. This project has been funded in whole or in part with Federal funds from the Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority (BARDA), under Contract No. HHSO100201600029C.

As of July 12, 2022, the phase 1 study (mRNA-1893-P201) is active in Puerto Rico, with a completion date scheduled for April 26, 2024. On August 3, 2022, Moderna confirmed that the mRNA-1893 Phase 2 study was ongoing.

The Lancet Infectious Disease published on January 19, 2023: Promising efforts to develop an mRNA vaccine against Zika. These findings support the continued development of mRNA-1893 against the Zika virus, which was well tolerated at all evaluated dose levels and induced strong Zika virus-specific serum nAb responses after two doses, regardless of baseline flavivirus serostatus. On April 20, 2023, the journal NPJ Vaccines published - The first-generation ZIKV mRNA vaccine, mRNA-1325, was initially generated, and as additional strain sequences became available, a second mRNA vaccine, mRNA-1893, was developed. Herein, we compared the immune responses following mRNA-1325 and mRNA-1893 vaccination and reported that mRNA-1893 generated comparable neutralizing antibody titers to mRNA-1325 at 1/20th of the dose and provided complete protection from ZIKV challenge in non-human primates. In-depth characterization of these vaccines indicated that the observed immunologic differences could be attributed to a single amino acid residue difference that compromised mRNA-1325 virus-like particle formation. These findings support the continued development of mRNA-1893 against Zika virus.

Headquartered in Cambridge, Mass., Moderna (Nasdaq: MRNA) currently has strategic alliances for development programs.

mRNA Technology

Recognizing the broad potential of mRNA science, Moderna set out to create an mRNA technology platform that functions very much like an operating system on a computer. It is designed to plug and play interchangeably with different programs. Generally, the only thing that changes from one potential mRNA medicine to another is the coding region – the actual genetic code that instructs ribosomes to make protein. Utilizing these instruction sets gives the investigational mRNA medicines a software-like quality. Moderna also can combine different mRNA sequences encoding for various proteins in a single mRNA investigational medicine.

mRNA-1893 Vaccine Indication

Zika virus is the first and only flaviviral disease the WHO (2016) declared a public health emergency because of devastating congenital disabilities following maternal infection. mRNA-1893 is indicated for avoiding transmission of the Zika disease from a mother to an unborn child.

mRNA-1893 Vaccine Dosage

Interim Phase 1 Data - All four cohorts (10 µg, 30 µg, 100 µg, 250 µg) of the Phase 1 study of mRNA-1893 have been dosed. An interim study analysis reports safety and immunogenicity data from the ten µg and 30 µg cohorts. In addition, neutralizing antibody titers were assessed using the Plaque Reduction Neutralization Test (PRNT50) and microneutralization assays (M.N.), which provide equivalent guidance for interpreting the neutralizing immune response.

mRNA-1893 Vaccine News

May 4, 2022 - Moderna confirmed the Phase 2 study of mRNA-1893 is ongoing in the U.S. and Puerto Rico and is being developed in collaboration with BARDA.

November 10, 2021 - The Hindustan Times reported that ZIKA virus cases had reached over 100 cases. Of the 105 positive cases, 17 are now negative.

November 4, 2021 - Moderna announced that its phase 2 study of mRNA-1893 is ongoing in the U.S. and Puerto Rico. mRNA-1893 is being developed in collaboration with BARDA. 

April 14, 2020 - The first interim analysis of the Phase 1 study shows that ten µg and 30 µg dose levels seroconverted 94% and 100% of seronegative participants, respectively, and effectively boosted seropositive participants; both dose levels were generally well-tolerated.

August 19, 2019 - Moderna Inc. announced that the Food and Drug Administration had approved its potential vaccine for the Zika virus for a fast track to approval. Fast Track is designed to facilitate the development and expedite the review of therapies and vaccines for serious conditions and to fill an unmet medical need. In addition, programs with Fast Track designation may benefit from early and frequent communication with the FD and a rolling marketing application submission. 

mRNA-1893 Vaccine Clinical Trials

mRNA-1893 Zika vaccine is currently being studied in two clinical trials. These were descriptive studies, with no formal hypothesis testing in either trial. Both trials are registered with ClinicalTrials.gov, NCT03014089 (mRNA-1325 trial) and NCT04064905 (mRNA-1893 trial).

Findings: The mRNA-1325 trial was done from Dec 14, 2016, to Aug 16, 2018. Ninety participants were enrolled: 53 (59%) participants were women, and 37 (41%) were men, 84 (93%) were White, and 74 (82%) were not Hispanic or Latino. All three dose levels of mRNA-1325 (10, 25, and 100 μg) were generally well tolerated, but the vaccine elicited poor Zika virus-specific nAb responses. At 28 days after dose two, geometric mean titres (GMTs) were highest for mRNA-1325 10 μg (10·3 [95% CI 5·9–18·2]). The mRNA-1893 trial was done from July 23, 2019, to March 22, 2021. One hundred twenty participants (70 [58%] women and 50 [42%] men) were enrolled, most participants were White (89 [74%]) and not Hispanic or Latino (91 [76%]). In the mRNA-1893 trial, solicited adverse reactions in participants who received a vaccine were mainly grade 1 or 2 and occurred more frequently at higher dose levels and after dose two. No participants withdrew due to an unsolicited treatment-emergent adverse event, and most of these events were not treatment-related. On day 57, all evaluated mRNA-1893 dose levels induced robust Zika virus-specific nAb responses, independent of flavivirus serostatus, that persisted until month 13. At day 57 in participants who were flavivirus seronegative, plaque reduction neutralization titre test nAb GMTs were highest for mRNA-1893 100 μg (454·2 [330·0–619·6]); in participants who were flavivirus seropositive, GMTs were highest for mRNA-1893 10 μg (224·1 [43·5–1153·5]) and mRNA-1893 100 μg (190·5 [19·2–1887·2]).

Flulaval Quadrivalent Influenza Vaccine 2023

GSK's Flulaval Quadrivalent is an inactivated influenza vaccine from viruses propagated in hens' eggs. Each of the four influenza viruses is produced and purified separately. The viruses are inactivated with ultraviolet light treatment followed by formaldehyde treatment, purified by centrifugation, and disrupted with sodium deoxycholate. Flulaval Quadrivalent (STN: BL 125163) is formulated without preservatives and does not contain thimerosal, according to the U.S. Food and Drug Administration (FDA). 

The World Health Organization (WHO) announced the flu vaccine composition for the 2023 southern hemisphere flu season. On March 7, 2023, the U.S. FDA presented the Influenza Virus Vaccine Strain Selection for the composition of the influenza vaccines for 2023-2024.

GSK confirmed on July 13, 2023, that it expects to distribute over 40 million doses of its influenza vaccine to the U.S. market. Both FLULAVAL QUADRIVALENT and FLUARIX QUADRIVALENT will be available in a 0.5mL, single-dose, pre-filled syringe and are indicated for patients six months and older for the current flu season in the U.S.

GlaxoSmithKline plc (GSK) is located in Brentford, United Kingdom, and Philadelphia, PA.

Flulaval Quadrivalent Indication

Flulaval Quadrivalent is indicated for active immunization to prevent disease caused by influenza A subtype and type B viruses in the vaccine. FLULAVAL QUADRIVALENT is approved for use in persons aged six months and older.

Flulaval Quadrivalent and COVID-19 Vaccines

The US Centers for Disease Control and Prevention (CDC) previously issued interim clinical considerations stating that 'COVID-19 vaccines and other vaccines, including influenza vaccines, can be administered without regard to timing.

Flulaval Quadrivalent Dosage

Flulaval Quadrivalent is approved for use in persons aged six months and older. Flulaval Quadrivalent is administered as an intramuscular injection. Do not administer Flulaval Quadrivalent to anyone with a history of severe allergic reactions (e.g., anaphylaxis) to any vaccine component, including egg protein, or following a previous dose of any influenza vaccine. For detailed dosage information, visit GSK.

Flulaval Quadrivalent Side Effects

Flulaval Quadrivalent is generally well-tolerated. Do not administer FLULAVAL QUADRIVALENT to anyone with a history of severe allergic reactions (e.g., anaphylaxis) to any vaccine component, including egg protein, or following a previous dose of any influenza vaccine. Suppose Guillain-Barré syndrome has occurred within six weeks of receipt of a prior influenza vaccine. In that case, the decision to give FLULAVAL QUADRIVALENT should be based on carefully considering the potential benefits and risks. Suppose you or your loved one has an adverse reaction to the vaccine. In that case, that information should be reported to VAERS, a U.S. passive reporting system that relies on individuals to send reports of their vaccine experiences. Anyone can submit a report to VAERS, including parents and patients. Furthermore, healthcare providers are required by law to report to VAERS.

Flulaval Quadrivalent News

September 12, 2023 - The U.S. CDC ACIP Releases 2023-2024 Influenza Vaccine Recommendations.

July 13, 2023 - GSK plc announced the availability of flu vaccines for the 2023-2024 season.

March 17, 2023 - The CDC weekly influenza surveillance reported seasonal influenza activity remains low nationally.

May 4, 2022 - Flu News Europe announced for week 16, of 39 countries and areas reporting on the intensity of influenza activity, 18 reported baseline intensity (across the Region), 14 reported low-intensity (across the Region), six reported medium-intensity (Denmark, Georgia, Kazakhstan, Latvia, Lithuania, and Romania), and one reported high-intensity (Estonia).

April 8, 2022 - The CDC FluView report indicated that Influenza activity increased nationally this week. Influenza activity is highest in the central and south-central regions of the country and is increasing in the northeastern regions.

November 11, 2021 - Despite increased influenza testing, levels continue to remain low, reported the WHO.

October 16, 2021 - The US CDC reported in week 41 that 0.1% of long-term care facilities reported > 1 influenza-positive test among residents. And no jurisdictions reported high or very high ILI activity.

October 7, 2021 - During week 40, the U.K. reported eight influenza-positive cases.

September 11, 2021 - Nationwide, during week 36, 2.3% of patient visits reported through ILINet were due to ILI. The percentage of patient visits for ILI remains below the baseline of 2.6% nationally.

September 4, 2021 - According to the US CDC, the percentages of visits for ILI reported in ILINet have been stable or decreasing among adult age groups (25-49 years, 50-64 years, and 65+ years) and may starting to stabilize among the younger age groups (0-4 years and 5-24 years).

August 26, 2021 - The U.S. FDA confirmed (30) lots of FluLaval Quadrivalent from I.D. Biomedical Corporation of Quebec has been released and is available for distribution in the USA.

July 26, 2021 - The global influenza vaccines market is projected to exceed the US$ 9.5 Billion mark by 2027 and present ample opportunities to the industry's players. In 2020, GlaxoSmithKline plc influenza vaccines (Fluarix/FluLaval) sales were up 35% from the previous year.

July 23, 2021 - GSK announced it started shipping its quadrivalent influenza vaccines to U.S. healthcare providers and pharmacies for the 2021-22 flu season. "GSK's focus continues to be increasing vaccination rates during the COVID-19 pandemic, and the flu vaccination is an integral part of that public health effort," said Judy Stewart, Senior Vice President and Head of U.S. Vaccines at GSK.

July 2, 2021 - The U.S. FDA issued a Supplement Approval letter to GSK for active immunization to prevent disease caused by influenza A subtype and type B viruses in the vaccine.

July 28, 2020 - GSK begins shipping a record number of its influenza vaccine doses for the 2020-21 season for the U.S. market. FLULAVAL QUADRIVALENT will be available in a 0.5mL, single-dose, pre-filled syringe and indicated for patients six months and older in line with CDC recommendations.

November 18, 2016 - GSK announced it had received approval from the U.S. Food and Drug Administration's (FDA) Center to expand the indication for FluLaval® Quadrivalent (Influenza Vaccine) to include use in children six months and older. Before this, the vaccine was only approved for active immunization against influenza A subtype and type B viruses in persons three years of age and older.

Flulaval Quadrivalent Clinical Trials

Flulaval Quadrivalent Influenza Vaccine has been tested in over 20 clinical trials.

Zika Vaccine VLA1601 Clinical Trials, Dosage, Indication, Side Effects

Valneva SE's VLA1601 is a second-generation, purified, inactivated whole Zika virus (ZIKV) vaccine candidate, adsorbed on aluminum hydroxide. As of December 2025, VLA1601 is the most advanced Zika vaccine developed and optimized on the original manufacturing platform of Valneva's licensed Japanese Encephalitis vaccine, IXIARO®. As of 2025, no preventive vaccines or effective treatments against ZIKV are approved by the U.S. Food and Drug Administration (FDA) or the European Medicines Agency (EMA). Zika is included in the FDA's Tropical Disease Priority Review Voucher Program. On August 12, 2025, the Company stated that no preventive vaccines or effective treatments are available and, as such, Zika remains a public health threat.

Valneva reported the results of its Phase 1 clinical trial (NCT03425149), showing immunogenicity and safety results for the tested doses and schedules. On March 26, 2024, Valneva announced the initiation of an additional Phase 1 clinical trial (VLA1601-102) to investigate the safety and immunogenicity of VLA1601 with a two-dose priming regimen on Days 1 and 29, with follow-up at 1 month (Day 57), 6 months, and 12 months. Primary Objectives: assessment of safety and tolerability up to 7 days after each vaccination and assessment of immunogenicity at Day 57 (1 month after completion of priming). Top-line data from this phase 1 clinical trial are expected in 2025. The Company has plans to expedite approvals with government agencies.

On November 4, 2025, Valneva announced positive results from its Phase 1 clinical trial (VLA1601-102, NCT06334393). The immune response induced by the double-adjuvanted VLA1601 vaccine candidate was significantly improved compared to the first-generation vaccine candidate, with higher peak seroconversion rates (>93% vs 86%) and a higher peak Geometric Mean Fold Increase in titers (>56-fold vs >7-fold). The Company stated: Despite the medical need, regulatory pathways and market opportunities for potential Zika vaccines remain uncertain. Valneva will therefore only consider further potential development steps for VLA1601 if concrete major private and public funding opportunities materialize.

France-based Valneva is a specialty vaccine company focused on developing vaccines for diseases with significant unmet needs. Valneva's vaccine portfolio includes two commercial vaccines for travelers. Valneva's 2023 Sustainability Report provides an in-depth account of the Group's activities and its future priorities. The Report's format is in accordance with French Decree No. 2017-1265 of August 9, 2017.

Zika Vaccine VLA1601 Indication

VLA1601 is a vaccine candidate indicated for the prevention of Zika infection. Vaccination should also protect against severe complications.

Zika Vaccine VLA1601 Dosage

In a phase 1 clinical trial, two doses of VLA1601 were administered intramuscularly in the deltoid muscle. Each dose is administered intramuscularly in the deltoid muscle on Days 0 and 28. Additionally, an accelerated vaccination schedule, administered on Days 0 and 7, was evaluated.

Zika Virus Impact

Zika was first identified in monkeys in Uganda in 1947 and later detected in humans in 1952. This mosquito-borne disease remains a public health threat throughout the Americas in 2025. According to the World Health Organization, there is a scientific consensus that ZIKV causes cases of microcephaly and Guillain-Barré syndrome. As of 2025, several countries and territories in the Americas, including Costa Rica and Puerto Rico, have reported evidence of mosquito-transmitted Zika virus infection.

On July 3, 2025, The Lancet published: A decade later, what have we learned from the Zika epidemic in children with intrauterine exposure? The Zika virus in pregnancy carries severe teratogenic potential to the fetus. Among children with congenital Zika syndrome, dysphagia and seizures are common, as are hospitalisations for pneumonia and urinary tract infections; overall, morbidity and mortality are extremely high. Children without congenital Zika syndrome but exposed to the Zika virus antenatally are also at risk of developmental disorders. Additionally, in utero exposure to the Zika virus does not lead to the production of neutralizing antibodies.

Zika Vaccine VLA1601 News

November 4, 2025 - Juan Carlos Jaramillo, M.D., Chief Medical Officer of Valneva, commented in a press release, "We are pleased by the notable safety and immunogenicity results demonstrated for our Zika vaccine candidate and especially our double-adjuvantation results."

February 18, 2025 - Valneca SE confirmed that Phase 1 results are forecasted for 2025.

October 10, 2024 - Valneva SE provided an update on its vaccine candidate.

March 26, 2024 - Juan Carlos Jaramillo, M.D., Chief Medical Officer of Valneva, said in a press release, "Valneva's commitment to our vision – to live in a world in which no one dies or suffers from a vaccine-preventable disease – fuels our pursuit for preparedness solutions against the Zika virus. As global temperatures rise and rainfall increases, the habitat for disease-carrying mosquitoes expands, presenting an ongoing public health challenge."

March 20, 2024 - Valneva SE stated that a vaccine against the Zika virus would complement the Company's portfolio of travel vaccines against mosquito-borne diseases, which already includes IXCHIQ® and IXIARO®.

November 9, 2023 - The Company announced the re-initiation of clinical development for ZIKA VACCINE CANDIDATE—VLA1601, with further program evaluation planned.

March 30, 2023 - Valneva's Chief Medical Officer, Juan Carlos Jaramillo, MD, will host a discussion on the opportunities and challenges of developing Zika vaccines on April 4, 2023.

VLA1601 Clinical Trial

In March 2024, Valneva initiated a Phase 1 clinical trial (NCT06334393) to investigate the safety and immunogenicity of VLA1601. As of November 4, 2025, the randomized controlled Phase 1 trial, VLA1601-102, enrolled approximately 150 participants aged 18 to 49 years in the U.S. Participants received two administrations of the highly purified, inactivated, aluminum-adjuvanted vaccine candidate VLA1601 at low, medium, or high doses, four weeks apart. In addition, the low dose of VLA1601 was evaluated with additional adjuvants, either the CpG 1018® adjuvant from Dynavax Technologies Corporation or the 3M-052-AF adjuvant from the Access to Advanced Health Institute. Data up to Day 57 (four weeks after the second dose) (Part A Analysis) showed that VLA1601 was generally safe and well-tolerated across all five treatment arms, with no safety concerns identified. Additionally, an independent Data Safety Monitoring Board found no safety issues. Two doses of VLA1601 were immunogenic across all five treatment arms investigated (i.e., alumadjuvanted Low, Medium, and High antigen dose; Low with additional adjuvants). The strongest immune response was observed in the double-adjuvant treatment arms (Low+alum+3M-052-AF and Low+alum+CpG1018) with statistically significantly higher neutralizing antibody titers (Geometric Mean Titers - GMTs) at Day 43 and Day 57 than in the single-adjuvant (alum) treatment arm. The immune response induced by the double-adjuvanted VLA1601 second-generation vaccine candidate was successfully improved compared to the first-generation vaccine candidate, with higher peak seroconversion rates (>93% vs 86%) and peak Geometric Mean Fold Increase of titers (>56 fold vs >7 fold)

Valneva concluded the Phase 1 trial for the first-generation vaccine (NCT03425149). It was first posted on February 7, 2018.