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Ervebo® (rVSVΔG-ZEBOV-GP) Ebola Vaccine Clinical Trials, Dosage, Efficacy, Indication, Side Effects

Merck Ervebo® Ebola Vaccine (rVSV-ZEBOV-GP, rVSV-ZEBOV, v920) is a live, recombinant, replication-competent Ebola virus zairense vaccine. Ervebo's active ingredient is Vesicular Stomatitis Virus (VSV), whose surface protein has been replaced with that of Ebola virus disease (EBOV). In addition, the Ervebo vaccine was genetically engineered to express the main glycoprotein from the Zaire ebolavirus, thereby provoking a neutralizing immune response. In November 2019, the World Health Organization (WHO) prequalified Ervebo. The U.S. Food and Drug Administration (FDA) issued STN: BL 125690/0 on December 19, 2019, and STN: BL 125690/55 on July 27, 2023. On August 3, 2023, the FDA approved (STN: 125690) an expanded indication for Ervebo for individuals 12 months and older. In Canada, Ervebo was approved in November 2022. 

Ervebo was granted Conditional Approval by the European Medicines Agency (EMA) for the European Union on November 11, 2019 (EMEA/H/C/004554). On July 20, 2023, the EMA's Committee for Medicinal Products for Human Use recommended the expanded approval of Ervebo for active immunization of individuals one year or older. As of September 7, 2023, Ervebo is indicated by the EMA (EMA/344888/2023) for the prevention of disease caused by Zaire ebolavirus in individuals 12 months of age and older living in Europe.

The Joint Project Manager for Chemical, Biological, Radiological, and Nuclear Medical (JPM-CBRN) helped provide a test that enabled Merck Sharp & Dohme B.V. to test human and non-human primate samples. The Ervebo vaccine protects people from Zaire but not against other Ebolavirus (Sudan) or Marburgvirus species. Additionally, it is unlikely that people could become infected with EBOV from the Ervebo vaccine, as it only contains one gene from the Ebola virus, not the entire virus. Specifically, it includes a gene for the EBOV glycoprotein that replaces the gene for the native VSV glycoprotein, says the U.S. Centers for Disease Control and Prevention (CDC). Merck and the U.S. government initially partnered in December 2014 through a third party, BioProtection Systems. In 2017, utilizing Project BioShield Act authority, U.S. BARDA funded work with Merck to continue late-stage development activities and began collaborating to expand ERVEBO's indication to include pediatrics. 

As of May 2024, the U.S. CDC reported that most doses (139,120; 95%) shipped from the ICG stockpile since 2021 have been repurposed for preventive vaccination of high-risk groups, compared with 6,570 (5%) used for outbreak response. The WHO's Annexes to the recommendations for using the Ebola vaccines, providing evidence to support the decision, were published in June 2024. As of April 2025, about 500,000 doses are stored in Switzerland. 

Drugbank's Accession Number: DB15595. ATC code: J07BX02. STN: 125690. Clinical Reviewer: Rebecca Reindel.

New Jersey-based Merck Sharp & Dohme LLC licensed the global R&D and manufacturing rights from Newlink Genetics Corp.'s phase I Ebola vaccine in 2014. The Public Health Agency of Canada, which initially developed the vaccine, retained noncommercial rights in the agreement.

Ervebo Vaccine Efficacy 

The Lancet Infectious Diseases, Volume 24, Issue 12, pp. 1357-1365, December 2024, confirms that rVSV-ZEBOV is highly protective against Zaire Ebolavirus disease and supports its use during outbreaks, even in challenging contexts, such as the eastern Democratic Republic of the Congo. A real-world study published on August 20, 2024, found that rVSV-ZEBOV was 84% effective against infection. On May 9, 2024, a preprint study published by The Lancet concluded that new data add further evidence of rVSV-ZEBOV safety and immunogenicity, including in people with pre-existing antibodies from suspected natural ZEBOV infection, which do not blunt the rVSV-ZEBOV immune response. On February 7, 2024, the Lancet Infectious Diseases published an analysis of all 2,279 patients with confirmed Ebola virus disease. rVSVΔG-ZEBOV-GP vaccination significantly lowered case fatality risk (vaccinated: 25% [106/423] vs not vaccinated: 56% [570/1015]; p<0·0001). A related commentary stated that this study shows that VSV-EBOV's protection extends beyond infection. The CDC evaluated vaccine efficacy in a two-part phase 3, open-label, cluster-randomized, controlled ring vaccination trial in Guinea during the 2014–2016 Ebola outbreak in West Africa. Based on cluster-level data, vaccine efficacy in the follow-up study was estimated at 100% (95% CI: 79.3%–100%).

Ervebo Vaccine Booster Dose

The Lancet Microbe published results from a study on October 4, 2024, which, in marked contrast to earlier trials evaluating short-term boosting, concluded. Delaying a rVSVΔG-ZEBOV-GP booster until month 18 resulted in an increase in GMT that remained several-fold above the GMT of the no-booster group for at least 18 months. These findings could have implications for defining the optimal timing of booster doses as preexposure prevention in populations at ongoing risk for Ebola virus exposure.

Ervebo Vaccine Availability

As of December 2024, the Ervebo vaccine was licensed in the U.S., U.K., European Union, Canada, Switzerland, Burundi, Central African Republic, the Democratic Republic of the Congo, Ghana, Guinea, Rwanda, Uganda, and Zambia. The Ervebo vaccine is not planned for commercial marketing in the U.S. but is maintained in the U.S. Strategic National Stockpile (SNS), with access facilitated by the U.S. government.

Ervebo Ingredients 

The inactive ingredients of this Ebola vaccine include recombinant human serum albumin and tromethamine (Tris) buffer, which contain a trace amount of rice protein.

Ervebo Indication

The Ervebo vaccine is indicated for the prevention of disease caused by Zaire ebolavirus in individuals 18 years of age and older. However, the duration of protection conferred by Ervebo is unknown. Additionally, the effectiveness of the vaccine when administered concurrently with antiviral medication, immune globulin, and/or blood or plasma transfusions is unknown. The WHO published the revised Ebola Vaccine FAQ, and the U.S. CDC published Ebola Vaccine: Information for U.S. Healthcare Providers. Merck advises against administering Ervebo to individuals with a severe allergic reaction (e.g., anaphylaxis) to any vaccine component, including rice protein.

Ervebo Dosage

The Ervebo vaccine is administered as a single-dose intramuscular injection in the top of your arm. Pre-vaccination serological screening is not required.

Ervebo Booster Dose

The U.S. FDA approves initial doses of ERVEBO for the prevention of EVD. Since an Ervebo vaccine booster dose is not an EMA or FDA-approved indication, the U.S. CDC sponsored an expanded access Investigational New Drug program in April 2022. This program allowed booster doses of preexposure prophylaxis for adults who were vaccinated at least 6 months prior and had a potential risk of occupational exposure to EBOV.

Ervebo Side Effects

On December 14, 2022, the NEJM published an Original Article confirming the safety and effectiveness of the ERVEDO vaccine. Do not administer ERVEBO to individuals with a history of a severe allergic reaction (e.g., anaphylaxis) to any vaccine component, including rice protein. Among 18,616 participants vaccinated with at least one dose of ERVEBO in clinical trials, 2 reported anaphylaxis. Injection-site side events include injection-site pain and redness.

The most common injection-site adverse events were injection-site pain (70%), swelling (17%), and redness(12%). The most common systemic adverse events reported following vaccination with ERVEBO were headache (37%), feverishness (34%), muscle pain (33%), fatigue (19%), joint pain (18%), nausea (8%), arthritis (5%), rash (4%), and abnormal sweating (3%). 

The safety and effectiveness of ERVEBO, a live virus vaccine, have not been assessed in immunocompromised individuals, and its effectiveness may be diminished in this population. The risk of vaccination with ERVEBO in immunocompromised individuals should be weighed against the risk of disease due to the Zaire ebolavirus.

Inform your healthcare provider promptly about any unusual or severe symptoms that occur after receiving this vaccine. You may also report any side effects to Merck Sharp & Dohme Corp, a Merck & Co., Inc. subsidiary, at 1-877-888-4231 or the Vaccine Adverse Event Reporting System (VAERS). The VAERS toll-free number is 1-800-822-7967, or you can report online at www.vaers.hhs.gov.

Ervebo Pregnant Women

Among immediately vaccinated pregnant women, 14 of 31 (45%) experienced pregnancy loss compared with 11 of 33 (33%) unvaccinated pregnant women (unadjusted RR: 1.35; 95% CI: 0.73–2.52). Overall, the pregnancy loss rate among pregnant women who received immediate vaccination was not statistically significantly higher than that among unvaccinated pregnant women. In addition, no external congenital anomalies were detected among live-born infants in either group (n = 44).

Ervebo U.S. CDC - FDA Presentations

The U.S. CDC published an update to the VIS sheet on June 30, 2022. On November 3, 2021, Jason Malenfant, MD, MPH, Epidemic Intelligence Service Officer, Viral Special Pathogens Branch, CDC, presented 'Evidence for Expansion of Recommendations for PreExposure Vaccination with rVSVΔG-ZEBOV-GP Ebola Vaccine for Special Pathogens Treatment Centers and Laboratory Response Network Facilities.' In addition, Wilbur Chen, MD, Chair of the Ebola Vaccine Working Group at the University of Maryland School of Medicine, presented an Overview. Caitlin Cossaboom, DVM, Ph.D., MPH, presented policy questions.

The U.S. FDA granted a Priority Review and a Tropical Disease Priority Review Voucher on September 17, 2019. The FDA also granted Breakthrough Therapy designation for Ervebo to facilitate the development and scientific evaluation of the vaccine. On December 19, 2019, the FDA announced the licensing of the Ervebo (rVSVΔG-ZEBOV-GP) Ebola Vaccine. On February 15, 2020, Merck announced that African countries, including the Democratic Republic of the Congo, Burundi, Ghana, and Zambia, had approved the use of Ervebo. On January 8, 2021, the U.S. CDC's Advisory Committee on Immvaccine Practices (ACIP) recommended the use of the rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo) in the U.S. for preexposure vaccination for adults aged ≥18 years who are at the highest risk for potential occupational exposure to Ebola virus species Zaire ebolavirus because they are responding to an outbreak of EVD, work as health care personnel at fedCDC'sy designated Ebola treatment centers in the USA, or work as laboratorians or other staff at biosafety level 4 facilities in the USA.

INO-4201 Booster Dose

A Phase 1b clinical trial evaluated the DNA vaccine candidate INO-4201 as a booster in healthy adult participants who had previously received a single injection of Ervebo. The prosecution was well tolerated and boosted humoral responses in all 36 participants (100%).

Thermostable Second-Generation Zaire Ebolavirus Vaccine

In November 2022, Hilleman Laboratories announced a collaboration with MSD to develop a thermostable second-generation Zaire ebolavirus vaccine candidate, building on MSD's approved ERVEBO®. In November 2023, SK Bioscience forged a development licensing agreement with Hilleman Laboratories for this second-generation Zaire Ebola virus vaccine candidate.

Ervebo Vaccine Price

This vaccine is not commercially available in the U.S. This UNICEF table shows the awarded price per dose, product, supplier, and calendar year based on a multi-year supply. Additional Ebola vaccine price information is available at InstantRx™.

Ervebo Vaccine News

September 14, 2025 - An initial 400 doses of the Ervebo Ebola vaccine—from the DRC's stockpile of 2000 doses prepositioned in the capital Kinshasa—have been delivered to Bulape.

September 4, 2025 - Health authorities in the Democratic Republic of the Congo announced that 2000 doses of Ervebo are already prepositioned in Kinshasa and will be quickly moved to Kasai to vaccinate contacts and frontline health workers.   

December 4, 2024 - Sierra Leone became the first country to launch a preventive Ebola vaccination campaign targeting 20,000 frontline workers in all 16 districts nationwide.

November 28, 2023, 9News reported that the staff at the Denver Health Regional Emerging Special Pathogen Treatment Center received the Ervebo vaccine as a preventive measure.

September 7, 2023 - "The European Commission's expanded approval of ERVEBO for children one year of age and older is an important milestone for the prevention of disease caused by Zaire ebolavirus," said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories.

April 27, 2022 - The DRC launched an Ebola vaccination in Mbandaka to halt the spread of the virus following an outbreak that has claimed two lives since April 21. Around 200 doses of the rVSV-ZEBOV Ebola vaccine will be deployed.

February 8, 2022 - A study published by PNAS examined the antibody response at 21 days and six months postvaccination after a single dose of rVSVΔG-ZEBOV-GP among EVD-exposed and potentially exposed populations in the DRC. At 21 days of follow-up, 87.2% had an antibody response. Additionally, 95.6% demonstrated antibody persistence at the six-month follow-up. These findings prove that antibody response and persistence after Ebola vaccination are robust in outbreak settings in the DRC.

November 3, 2021: The U.S. CDC's vaccine advisory committee voted to support vaccines as PrEP for certain healthcare personnel and/or lab support staff at facilities that handle Ebola virus specimens.

October 13, 2021—The WHO confirmed that a vaccination program related to the new Ebola outbreak had been launched in the DRC.

October 11, 2021 - The CEO of GAVI Tweeted,' About 1,000 doses of the rVSV-ZEBOV vaccine are still available in the country (DRC), so vaccination can start immediately to contain this outbreak. And 248,500 supported doses are available in the global stockpile and ready to ship in case of. Need' @GaviSeth.

January 27, 2021—The journal Nature published a new study titled "Ebola virus antibody decay: stimulation in a high proportion of survivors." The study observed the highest antibody reactivity around 200 days after recovery. The model suggests that EBOV antibody reactivity declines over 0.5–2 years after recovery. In a high proportion of healthy survivors, antibody responses undergo rapid restimulation.

February 14, 2020 - Merck confirmed that four African countries approved the ERVEBO vaccine. ERVEBO has now been registered in the following African countries: DRC, Burundi, Ghana, and Zambia.

December 1920—The U.S. FDA announced the approval of Ervebo, the first FDA-approved vaccine for preventing the Ebola virus disease caused by the Zaire ebolavirus.

May 23, 2019 - The School of Public Health Ethics Committee of the University of Kinshasa approved the compassionate belt vaccination protocol amendment for the rVSV-ZEBOV vaccine to expand its targets to pregnant women after the first trimester and lactating women identified as contacts. It is maintained that children can be vaccinated from 6 years old. Between November 26, 2018, and May 26, 2019, 319 pregnant women and 603 lactating women who were registered as contacts were unable to receive vaccination.

July 25, 2016 - Merck announced two regulatory milestones for its investigational vaccine for Ebola Zaire, V920 (rVSV∆G-ZEBOV-GP, live attenuated): the U.S. Food and Drug Administration has granted Breakthrough Therapy Designation to the vaccine candidate, and the European Medicines Agency has granted PRIME status.

December 23, 2015: Merck announced the Emergency Use Assessment and Listing application for its investigational Ebola Zaire vaccine, V920 (rVSV∆G-ZEBOV-GP, live attenuated), which the World Health Organization accepted for review.

Ervebo Clinical Trials

Merck Announces FDA Approval for ERVEBO® (Ebola Zaire Vaccine, Live). Clinical trial information is available on the Merck Vaccines website.

Stamaril® Yellow Fever Vaccine Clinical Trials, Dosage, Efficacy, Side Effects, Usage

Sanofi Stamaril® (17D-YFV, 17D-213) is a live, attenuated yellow fever vaccine containing the active Yellow fever virus 17D-204 strain produced in specified pathogen-free chick embryos. This yellow fever vaccine contains less than one mmol of sodium (23 mg) per dose, essentially "sodium-free," and less than one mmol of potassium (39 mg) per dose. In addition, this yellow fever vaccine contains approximately 8 mg of sorbitol per dose. Efficacy results, including neutralizing antibodies and a robust T-cell response, were reported in a peer-reviewed 2016 study. In addition, the humoral and cellular immunity elicited by 17D has been well characterized in humans, according to the World Health Organization (WHO).

The duration of protection against yellow fever after a single 0.5 mL dose of Stamaril is expected to be at least 10 years. The 17D line of yellow fever virus vaccines is among the most effective vaccines ever created, according to a 2017 study. Stamaril is considered investigational in the U.S. and is not a U.S. Food and Drug Administration (FDA) licensed product. As of May 6, 2021, shipments of Stamaril under the U.S. Expanded Access Program were discontinued. Product information is available in Canada, Australia, and the UK. On July 4, 2021, the European Medicines Agency (EMA)  published EMEA/169383/2006. Various E.U. countries authorize Stamaril. Stamaril's ATC code is J07BL; the Drugbank Accession Number is DB10805. 

With some exceptions, a single dose of the YF vaccine appears to confer lifelong protective immunity against YF disease. Reinforcing immunization (booster dose) should be offered to a small subset of travelers who may be at continued risk, such as those traveling to the UK, according to the Health Security Agency guidance.

Sanofi is a global biopharmaceutical company dedicated to supporting people through their health challenges, with a focus on human health.

Stamaril Vaccine Availability 2025

As of 2025, Stamaril is available in 70 countries; however, the United Kingdom was not among them in late June 2025. However, the UK expects to have access to Stamaril on August 15, 2025.

Sanofi Pasteur's Stamaril has been offered in Europe, including Scotland and the UK, as well as in Uganda, Nigeria, New Zealand, the Republic of Congo, and the Americas Region, including Argentina, Brazil, and Colombia. Between 2023 and 2024, over 80 million people in Africa were protected through vaccination campaigns. In April 2024, Uganda's Karamoja, Teso, Masaka, Ankole, and Kampala Metropolitan regions are among the areas where 14 million people are being vaccinated. The WHO strategy, led by PAHO, aims to vaccinate nearly 1 billion people by 2026. From January 2021 to August 2022, a total of 3,991,568 persons were vaccinated with Stamaril.

Stamaril Coadministration

A non-peer-reviewed study conducted by researchers in Europe evaluated the safety and immunogenicity of the simultaneous delivery of the Yellow fever virus (YFV) vaccine with Tickborne encephalitis virus (TBEV) and Japanese encephalitis virus (JEV) vaccines in an open-label, non-randomized clinical trial. Published on July 11, 2022, the Conclusions are: Inactivated TBEV or JEV vaccines can be coadministered with the live attenuated YFV vaccine without an increased risk of adverse events and reduced development of nAbs to the respective viruses. Furthermore, the vaccines can be safely administered in the same upper arm without adverse outcomes.

Stamaril Indication

Stamaril vaccination is indicated for active immunization against yellow fever for adults and children aged nine months and older when traveling to, passing through, or living in an endemic area, traveling to any country that requires an International Certificate of Vaccination for entry (which may or may not depend on the previous itinerary), and handling potentially infectious materials (e.g., laboratory personnel). The vaccine should be given at least ten days before entering an endemic area, as protective immunity may not be achieved until this time has elapsed. Children aged 6-9 months should be vaccinated only under exceptional circumstances.

On November 16, 2021, the UK Medicines and Healthcare Products Regulatory Agency published a standardized pre-vaccination checklist to ensure the yellow fever vaccine is indicated for the intended travel destination and to enable vaccinators to identify existing contraindications or precautions in individuals before vaccination.

Stamaril Dosage

The Stamaril yellow fever vaccine should be administered at least ten days before entering an endemic area, as protective immunity may not be achieved until this time has elapsed. According to the CDC, Stamarila is a single, 0.5-milliliter dose given to adults and children from 9 months of age. However, a yellow fever booster with one dose (0.5 milliliters) may be necessary if you or your child had an insufficient response to the first dose or if it has been at least ten years since the initial dose, as required by some countries as a condition of entry, according to the CDC.

Stamaril Fractional Dose

The Lancet Infectious Diseases published a study on April 28, 2023: Immunogenicity and safety of fractional doses of 17D-213 yellow fever vaccine in children: a randomized, double-blind, non-inferiority substudy of a phase 4 trial. Conclusions: Fractional doses of the 17D-213 vaccine were non-inferior to standard doses in inducing seroconversion 28 days after vaccination in children aged 9–59 months when assessed with PRNT50. However, we found fewer children seroconverted at ten days. The results support the use of fractional doses of yellow fever vaccines in WHO recommendations for outbreak response in the event of a yellow fever vaccine shortage, including in children. A 2018 study reported that a one-fifth fractional dose of the Stamaril yellow fever vaccine elicits protective antibodies. However, this suggestion is not approved by the FDA, CDC, or EMA.

Stamaril Side Effects

According to a study published on March 31, 2023, 627.079 individuals received STAMARIL from May 2017 through June 2021; of these, 1308 (0.2%) reported at least one adverse event (AE), of which 122 reported at least one Severe AE. The following serious side effects have sometimes been reported, including Allergic reactions. In addition, reactions affecting the brain and nerves may occur within one month of the vaccination and sometimes be fatal.

Stamaril Women

If you are pregnant or breastfeeding, think you may be pregnant, or plan to have a baby, ask your healthcare professional for advice. You should not receive STAMARIL during pregnancy or breastfeeding unless this cannot be avoided. Also, you are recommended not to become pregnant within one month after receiving STAMARIL. Your healthcare professional can advise you on whether you must be vaccinated. If vaccination is needed, it is recommended to interrupt breastfeeding for at least two weeks after receiving STAMARIL. Consult your healthcare professional if you receive the vaccine while pregnant or breastfeeding.

The CDC says, 'the Yellow fever vaccine has been given to many pregnant women without any apparent adverse effects on the fetus. However, because the yellow fever vaccine is a live-virus vaccine, it poses a theoretical risk, according to the CDC. Pregnant women should avoid or postpone travel to an area with a risk of yellow fever. If travel cannot be avoided, discuss vaccination with your healthcare provider before departure,' says the CDC.

Stamaril and HIV

The Lancet published a study on April 28, 2023, that provides confidence that fractional dose recommendations apply to populations with high HIV prevalence.

Stamaril Immunocompromised

Randomized and quasi-randomized clinical trials and observational studies that included immunocompromised participants (individuals with HIV infection, organ transplants, and cancer who used immunosuppressive drugs for rheumatologic diseases and those on immunosuppressive therapy for other diseases) were selected. Study Conclusions - It is impossible to affirm that immunocompromised individuals, regardless of etiology, have a higher risk of adverse events after receiving the YF vaccine.

Stamaril Vaccine News

June 27, 2025 - There will be a brief disruption in the supply of the yellow fever vaccine, Stamaril, in the UK.

November 8, 2024 - The Republic of Colombia recently conducted a Stamaril vaccination campaign. 

April 11, 2024 - Uganda launches phase 2 of the yellow fever vaccination campaign for 14 million people.

January 4, 2024 - Phylogenetic analysis reveals a new introduction of the Yellow Fever virus in São Paulo State, Brazil, 2023.

April 28, 2023 - The Lancet published an article: Fractional dose yellow fever vaccination, coming of age.

March 15, 2023 - Uganda launched an extensive vaccination program (1.9 million) for children.

February 8, 2023—The Tribune Online reported that Nigeria's Bayelsa State Government declared a state of emergency regarding yellow fever vaccination.

January 3, 2022 - The WHO Africa reported that 4,385,320 persons were vaccinated in Cameroon, the Central African Republic, Chad, Ghana, and Kenya from 2021 through December 7, 2022.

December 12, 2022 - The WHO Africa reported that 81 children received life-saving yellow fever vaccines in eastern Nigeria.

September 22, 2022 - The Republic of Uruguay required proof of a yellow fever vaccine for certain people visiting or departing from the country.

August 5, 2022 - The Republic of the Congo launched a yellow fever vaccination campaign to vaccinate 4 million people.

March 2, 2022 - The temporary low-stock situation in the UK has been resolved.

December 1, 2021—The WHO reported that since November 6, 2021, a focused vaccination campaign targeting 54,964 people aged 6 months to 60 years (excluding pregnant women) has been conducted in over 80 communities in the West and North Gonja districts of the Savannah region. The International Coordinating Group on Vaccine Provision for Yellow Fever has approved a campaign targeting 361,165 people (9 months to 60 years) in five affected districts.

April 2021—The U.S. CDC confirmed Pasteur's announcement that YF-VAX is once again available for purchase in the U.S.

March 9, 2021 - The Canadian Committee to Advise on Tropical Medicine and Travel Interim Canadian recommendations for using a fractional yellow fever vaccine during a vaccine shortage.

June 25, 2020 - To help meet the continued yellow fever vaccination needs in the U.S., STAMARIL® (Yellow Fever Vaccine [Live]) will continue to be available throughout 2020.

December 23, 2019 – To help meet the continued demand for the yellow fever vaccine in the USA, the manufacturer of the STAMARIL vaccine announced that it would continue to be available throughout 2020.

May 8, 2019 – A long-term study found no evidence that a YF vaccination in dengue-endemic areas increased the risk of severe dengue fever.   

May 2, 2019 – The FDA licensed a new state-of-the-art Yellow Fever Vaccine production facility in the USA.

November 27, 2018 – A study reported that a one-fifth fractional dose of the Stamaril (17D-YFV) yellow fever vaccine delivers protective antibodies for up to 10 years.

Stamaril Yellow Fever Vaccine Clinical Trials

Sanofi's Stamaril yellow fever vaccine has been involved in multiple clinical trials.

Phase 4 Clinical Trial NCT02991495: Immunogenicity and Safety of Fractional Doses of Yellow Fever Vaccines. Last Update Posted: December 17, 2020. Estimated Study Completion Date: May 31, 2021. This study aims to answer research questions that will broaden the recommendations for the use of fractional doses of the yellow fever vaccine in emergencies. The study will be conducted in Uganda and Kenya. The primary objective of assessing non-inferiority is to compare seroconversion rates 28 days after vaccination with a fractional dose to those with the total amount for each WHO-prequalified manufacturer. In addition, the Safety Monitoring Board will review the main outcome vaccine results for the studies in children and HIV-positive adults.

Phase 3 Clinical Trial NCT03541694: Passive Enhanced Safety Surveillance of Stamaril Vaccine in Korea. Last Update Posted: March 26, 2019. This is a passive enhanced safety surveillance study of the Stamaril vaccine in Korea. The objective is to collect suspected adverse events related to vaccination with Stamaril in routine practice.

A Phase I, open-label, randomized, controlled clinical study where healthy adults received SII YFV intramuscularly (SII YFV IM), SII YFV subcutaneously (SII YFV SC), or STAMARIL® (Sanofi-Pasteur) in a 1:1:1 ratio. They were followed for solicited reactions over 10 days, unsolicited events over 28 days, and serious adverse events over 3 months. YF-neutralizing antibodies were measured at baseline and on Days 10, 14, and 28. A total of 60 adults were enrolled in the study. The proportions of participants with solicited reactions were 10%, 40%, and 25% in the SII YFV SC, SII YFV IM, and STAMARIL® arms, respectively. No causally related unsolicited events or serious adverse events were reported. After vaccination, seroconversion rates were 94.44%, 100%, and 100% in the three arms, respectively. The post-vaccination geometric mean titers were similar in the study arms. The new YFV was found to be safe and immunogenic when administered by both IM and SC routes. The vaccine can be tested in further phases of clinical studies.

Pneumovax®23 Vaccine 2022

Merck's PNEUMOVAX®23 (Pneumococcal Vaccine Polyvalent) is a vaccine that can help protect against infection by 23 types of pneumococcal bacteria, common and often cause serious illnesses. Pneumovax 23 vaccine contains 23 serotypes (1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19F, 19A, 20, 22F, 23F, and 33F). PNEUMOVAX 23 is approved for use in persons 50 years of age or older and persons aged ≥2 years who are at increased risk for pneumococcal disease.

On October 23, 2020, a study published by PLOS concluded 'That PPV23 vaccination provides moderate long-term protection against hospitalization with PPV23 serotype pneumonia. And, PPV23 vaccination may continue to have an important role in national pneumococcal immunization policies, including the possibility of revaccination of older adults.' In a group of 2,357 patients (717 PPV23 cases, 1,640 controls) with an average time of 10 years since PPV23 vaccination, we estimated the VE of PPV23 against PPV23 serotype pneumonia to be 24% after adjustment for patient factors (95% CI 5%–40%, p = 0.02).

The U.S. Centers for Disease Control and Prevention published on January 28, 2022, newly simplified recommendations for pneumococcal vaccination in the elderly and immunocompromised. The changes were published in the Morbidity and Mortality Weekly Report. Vaccination with PNEUMOVAX 23 may not offer 100% protection from pneumococcal infection.

Merck Sharp & Dohme Corp. is an American multinational pharmaceutical company and one of the world's largest pharmaceutical companies.

Pneumovax 23 Indication

The global prevalence of pneumococcal disease, an infection caused by Streptococcus pneumoniae, is evolving, says the U.S. CDC. Highly aggressive strains, or serotypes, threaten to put more people at risk for non-invasive pneumococcal illnesses such as pneumonia (when it is confined to the lungs), sinusitis, and otitis media (middle ear infection); and invasive pneumococcal illnesses such as bacteremia (infection in the bloodstream), bacteremic pneumonia (pneumonia with bacteremia) and meningitis. 

The pneumococcal disease includes pneumococcal infections of the lung, blood, and coverings of the brain and spinal cord. Pneumovax 23 will not prevent disease caused by capsular pneumococcus types other than those contained in the vaccine. PNEUMOVAX 23 will not prevent disease caused by capsular types of pneumococcus other than those contained in the vaccine.

Additionally, the U.S. CDC recommends for people with certain chronic conditions such as diabetes, heart disease, or COPD and are 19 to 64 years old, 1 dose of PCV15 followed by PNEUMOVAX 23 or 1 dose of PCV20. Do not administer PNEUMOVAX 23 to individuals with a history of a hypersensitivity reaction to any vaccine component. Defer vaccination with PNEUMOVAX 23 in persons with moderate or severe acute illness. Use caution and appropriate care in administering PNEUMOVAX 23 to individuals with severely compromised cardiovascular and/or pulmonary function in whom a systemic reaction would pose a significant risk.

Available human data from clinical trials of PNEUMOVAX 23 in pregnancy have not established the presence or absence of a vaccine-associated risk. Since elderly individuals may not tolerate medical interventions as well as younger individuals, a higher frequency and/or greater severity of reactions in some older individuals cannot be ruled out. Persons who are immunocompromised, including persons receiving immunosuppressive therapy, may have a diminished immune response to PNEUMOVAX 23.

Pneumovax 23 Dosage

Pneumovax 23 is administered as an intramuscular or subcutaneous injection only. Pneumovax 23 is for people 50 years of age and older and is approved for persons aged ≥2 years who are at increased risk for pneumococcal disease. And if you are 65 years or older, the U.S. CDC recommends either one dose of PCV15 followed by Pneumovax 23 or one dose of Prevnar 20.

Intervals between PCV and PPSV23. Findings from eight immunogenicity studies that evaluated the immune response after a sequence of 7-valent PCV, PCV13, or PCV15 followed by PPSV23 administered at intervals of 2, 6, or 12 months or 3–4 years were reviewed (16–18,25–29). Three studies comparing intervals ranging from 2 to 6 months between administration of PCV and PPSV23 found no significant difference in immunogenicity measured after PPSV23 receipt, although reactogenicity tended to be higher with shorter intervals (25–29). In a study that compared antibody responses to 1 dose of PCV13 with responses to PCV13 followed by PPSV23 1 year apart, the immune responses following PPSV23 were significantly lower compared with the responses after a dose of PCV13 for eight of 12 common serotypes. In another study that compared antibody response to 1 dose of PCV13 with responses to PCV13 followed by PPSV23 approximately 4 years apart, the immune responses following PPSV23 were significantly higher for seven of 12 common serotypes (26). These findings suggested that longer intervals between administration of PCV and PPSV23 might improve immunogenicity in immunocompetent adults, although a direct comparison between a 1- versus 4-year interval was not made.

Pneumovax 23 Sales in 2021

Merck & Co. reported on February 3, 2022, lower sales of PNEUMOVAX 23, which declined 14% to $292 million, primarily driven by lower demand in the U.S.

Pneumovax 23 News 2021 - 2022

November 11, 2021 - This year's World Pneumonia Day theme is Stop Pneumonia/Every Breath Counts.  

June 9, 2021 - As reported by Barron's, the U.S. Food and Drug Administration approved Pfizer's updated pneumococcal vaccine (Prevnar 20) for adults late Tuesday in a development that positions the drug giant for a battle with Merck as both hope to win supremacy in the lucrative market.

April 29, 2021 - Merck confirmed Pneumovax 23 sales decreased by 36% last year.

October 23, 2020 - A case-control test-negative design study: Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against vaccine serotype pneumococcal pneumonia in adults. In establishing an established national childhood PCV13 vaccination program, PPV23 vaccination of clinical at-risk patient groups and adults aged ≥65 years provided moderate long-term protection against hospitalization with PPV23 serotype pneumonia. These findings suggest that PPV23 vaccination may continue to have an important role in adult pneumococcal vaccine policy, including the possibility of revaccination of older adults.

September 25, 2020 - The U.S. FDA approved Merck's request submitted and received November 26, 2019, to supplement your Biologics License Application under section 351(a) of the Public Health Service Act for Pneumococcal Vaccine, Polyvalent, PNEUMOVAX® 23 manufactured at your West Point, Pennsylvania facility to update the package insert to include data on the sequential administration of Prevnar 13® and PNEUMOVAX® 23 in Sections 6.1 Clinical Trials Experience and 14.2 Immunogenicity.

July 20, 2020 - Time for a third-generation pneumococcal conjugate vaccine.

June 22, 2020 - Merck announced results from two initial Phase 3 studies evaluating the safety, tolerability, and immunogenicity of V114, the company's investigational 15-valent pneumococcal conjugate vaccine. These data, in addition to results from V110-029, a study evaluating PNEUMOVAX ® 23 in healthy adults 50 years of age or older, were published via the International Symposium on Pneumococci and Pneumococcal Diseases online digital library.

January 31, 2020 - Updated Pneumococcal Vaccine Recommendations for Older Adults.

November 26, 2019 -  The U.S. FDA stated: 'We have approved your request submitted and received June 4, 2019, to supplement your Biologics License Application under section 351(a) of the Public Health Service Act for Pneumococcal Vaccine Polyvalent (PNEUMOVAX®23) manufactured at West Point, Pennsylvania. We hereby approve the draft package insert labeling submitted under Amendment 5001, dated November 8, 2019.'

Pneumovax 23 Vaccine Clinical Trials

Mercks' Pneumovax 23 has been in numerous clinical trials to test the safety, tolerability, and immunogenicity. 

Menveo Vaccine Clinical Trials, Dosage, Efficacy 

GSK's Menveo helps protect appropriate adolescent patients with a primary and booster dose of MENVEO. It consists of two portions: 10 µg of lyophilized meningococcal serogroup A capsular polysaccharide conjugated to CRM197 and 5 μg each of capsular polysaccharide of serogroup C, W, and Y conjugated to CRM197 in 0.5 mL of phosphate-buffered saline, which is used to reconstitute the lyophilized MenA component. Menveo does not prevent N. meningitidis serogroup B infections. The immunogenicity of MENVEO was evaluated 28 days after vaccination in a pivotal noninferiority trial that compared MENVEO with Menactra. The primary endpoint was the percentage of subjects with a seroresponse 28 days after a dose of either MENVEO or Menactra.

The European Commission approved a single-vial, fully liquid presentation of Menveo (Meningococcal Group A, C, W-135, and Y conjugate vaccine, MenACWY vaccine) in November 2024 to help protect against invasive meningococcal disease (IMD) caused by bacterial serogroups A, C, W, and Y.

This single-vial presentation is now licensed for active immunization of children from 2 years to adolescents and adults. It offers healthcare providers an option that does not require reconstitution before use.

The U.S. Prescribing Information is available at this weblink. GSK Medical Information: 1-877-GSK-MI4U (1-877-475-6448). The U.S. CDC Advisory Committee on Immunization Practices (ACIP) vaccine committee reviewed the Menveo One-Vial Presentation on October 20, 2022, led by Sam Crowe, Ph.D., MPH Work Group Lead.

Menveo Indication

Menveo is indicated for active immunization to prevent invasive meningococcal disease caused by Neisseria meningitidis serogroups A, C, Y, and W-135. The U.S. CDC recommends MenACWY vaccination for children who are between 2 months and 10 years old if they:

• Have a rare type of immune disorder called complement component deficiency
• Are taking a type of medicine called a complement inhibitor (for example, Soliris® or Ultomiris®)
• Have a damaged spleen or sickle cell disease, or their spleen has been removed
• Have HIV
• Are traveling to or residing in countries in which serogroup A, C, W, or Y meningococcal disease is common
• Are part of a population identified to be at increased risk because of a serogroup A, C, W, or Y meningococcal disease outbreak

All 11 to 12-year-olds should get a MenACWY vaccine, with a booster shot at 16 years old.

Menveo Dosage

MENVEO is approved for use in individuals 2 through 55 years and administered as an intramuscular injection. In children initiating vaccination at 2 months of age, Menveo is to be administered as a 4-dose series at 2, 4, 6, and 12 months of age. 

Menveo Adverse Reactions

Common solicited adverse reactions among children initiating vaccination at 2 months of age and receiving the 4-dose series were tenderness and erythema at the injection site, irritability, sleepiness, persistent crying, change in eating habits, vomiting, and diarrhea at 7 months through 23 months of age and receiving the 2-dose series were tenderness and erythema at the injection site, irritability, sleepiness, persistent crying, change in eating habits, and diarrhea; at 2 through 10 years of age who received Menveo were injection site pain, erythema, irritability, induration, sleepiness, malaise, and headache. Common solicited adverse reactions among adolescents and adults aged 11 through 55 years who received a single dose of Menveo were pain at the injection site, headache, myalgia, malaise, and nausea. Across all age groups, some events were severe. Similar rates of solicited adverse reactions among adolescents and adults were observed following a single booster dose.

Menveo Vaccine News

November 27, 2024—Philip Dormitzer, GSK Head of Global Vaccines Research & Development, said: "As a leader in meningococcal vaccines, GSK is dedicated to finding innovative solutions that simplify immunization and support vaccine uptake. We remain committed to safeguarding individuals from bacterial meningitis and will persist in our efficacy in preventing devastating disease among at-risk populations in the European Union."

October 17, 2022 - GSK announced that the US FDA had approved a new presentation of Menveo for individuals aged 10 to 55 years to help prevent invasive meningococcal disease caused by Neisseria meningitidis serogroups A, C, Y, and W. The Menveo one-vial presentation now comes in a ready-to-use single vial, giving healthcare providers a more convenient option.

August 18, 2022—Florida Health departments offer meningococcal vaccines for free. The state has been experiencing an outbreak this year, recording over 50 cases. February 9, 2022 - GSK reported that during 2021, Menveo sales were up 3% AER 9% CER to £272 million, primarily driven by 2020 cohort catch-up vaccinations and 2021 higher demand, as well as increased market share in the U.S.

Menveo Clinical Trials

GSK's Menveo has been involved in many clinical trials.