Bavarian Nordic Provides Update on COVID-19 Booster Vaccine Program

  • ABNCoV2 and the comparator vaccine demonstrated a reduced level of neutralizing antibodies against a circulating variant (Omicron XBB.1.5) in Phase 3 study.
  • cVLP platform has proven its ability to induce strong and lasting immunity against the target virus, but Bavarian Nordic sees no commercial opportunity for the vaccine, as the platform is not suitable for quick adaptions to emerging variants.
  • The Company will continue its dialogue with authorities on how best to leverage the learnings about the platform in a potential future pandemic situation.

COPENHAGEN, Denmark, August 31, 2023 – Bavarian Nordic A/S (OMX: BAVA) today reported additional Phase 3 results and provided an update on the development program for its cVLP-based COVID-19 booster vaccine candidate, ABNCoV2.

As previously reported, two weeks post a booster vaccination with ABNCoV2, the levels of neutralizing antibodies against the original SARS-CoV-2 variant (Wuhan index virus) were non-inferior to those stimulated in people vaccinated with Comirnaty® and this result met the primary objective of the Phase 3 study. The Wuhan variant is no longer the primary concern, as the virus has mutated creating new circulating variants, such as Omicron XBB.1.5. In a follow-up analysis, when looking at this more distant variant, the levels of neutralizing antibodies induced by ABNCoV2 were lower than those stimulated by the non-adapted Wuhan-based Comirnaty, and fewer people had detectable antibodies following ABNCoV2 (64%) versus Comirnaty (85%). The levels of neutralizing antibodies induced by both vaccines were much lower than against the Wuhan variant.

A 6-month follow-up analysis will be conducted to evaluate the durability of the antibody responses from booster vaccination with ABNCoV2 and Comirnaty, which, if the Phase 2 durability results for ABNCoV2 are confirmed, may confirm an advantage over the comparator vaccine.

While safety data from the Phase 3 study will continue to be collected for 6 months, safety data from 4,205 individuals followed up for 2 months post vaccination showed ABNCoV2 to be well-tolerated with no serious adverse events being reported.

These data support the current position of many of the regulators (e.g. FDA, EMA and WHO) that request variant-specific COVID vaccines that will likely have to be adapted each year like flu vaccines. Unfortunately, ABNCoV2 cannot be readily adapted within the seasonal timeframe and as such ABNCoV2 no longer represents a commercial opportunity for Bavarian Nordic.

Despite the lack of efficacy against distant and less virulent variants, the data generated in the overall development of ABNCoV2 may support the use of the cVLP platform in future pandemics, and the Company will discuss with the authorities how best to leverage the learnings from this development program.

Paul Chaplin, President and CEO of Bavarian Nordic said: “The world is in a different place now, and COVID-19 is no longer a public health crisis. However, as the disease continues to evolve, innovations in vaccine development are still warranted. We have generated robust data, so far demonstrating a favorable safety profile for the vaccine along with the ability to induce a strong and persistent immune response against earlier and more virulent strains, confirming the viability of the cVLP platform. We would like to thank our partners and everyone taking part in the Phase 3 study, and not least the Danish Ministry of Health for their support in this development that has validated a new vaccine platform for future pandemics.”

About ABNCoV2
ABNCoV2 is a COVID-19 booster vaccine candidate, initially developed by AdaptVac using their proprietary capsid virus like particle (cVLP) technology. Bavarian Nordic licensed the vaccine in 2020 and has sponsored the clinical development beyond Phase 1, which was conducted under a Horizon 2020 EU grant to AdaptVac and the PREVENT-nCoV consortium. 

Results from a Phase 2 trial, which enrolled individuals that were previously vaccinated with approved mRNA vaccines, demonstrated the ability of ABNCoV2 to significantly boost the existing levels of SARS-CoV-2 neutralizing antibodies against both the Wuhan variant and former variants of concern (Alpha, Beta, Delta and Omicron) to levels reported to be highly efficacious (>90%)[1] against SARS-CoV-2. A follow-up study of a subset of individuals in the study showed that 12 months post the booster with ABNCoV2, neutralizing antibodies against the Wuhan strain and former variants of concern remained at levels known to be associated with a high level of protection.

The Phase 3 study was designed to demonstrate non-inferiority of ABNCoV2 to Comirnaty® measured by neutralizing antibodies against the SARS-CoV-2 virus (Wuhan wild type). The study enrolled a total of 4,205 adults who either previously completed primary vaccination or had already received one booster dose of a licensed COVID-19 vaccine. The active, controlled part enrolled 622 participants who were randomized to receive either a single 100 µg dose of ABNCoV2, or a single 30 µg adult booster dose of Comirnaty. The second part of the study evaluated the safety and tolerability of a single 100 µg dose of ABNCoV2 in 3,583 participants.

The Phase 3 development of ABNCoV2 was partly funded through an agreement with the Danish State. 

About Bavarian Nordic
Bavarian Nordic is a fully integrated vaccine company focused on the research and development, manufacturing and commercialization of life-saving vaccines. We are a global leader in smallpox and mpox vaccines, which have been developed through our long-standing partnership with the U.S. Government to enhance public health preparedness and have a strong portfolio of vaccines for travelers and endemic diseases. For more information visit

Forward-looking statements
This announcement includes forward-looking statements that involve risks, uncertainties and other factors, many of which are outside of our control, that could cause actual results to differ materially from the results discussed in the forward-looking statements. Forward-looking statements include statements concerning our plans, objectives, goals, future events, performance and/or other information that is not historical information. All such forward-looking statements are expressly qualified by these cautionary statements and any other cautionary statements which may accompany the forward-looking statements. We undertake no obligation to publicly update or revise forward-looking statements to reflect subsequent events or circumstances after the date made, except as required by law.

Europe: Rolf Sass Sørensen, Vice President Investor Relations, Tel: +45 61 77 47 43
US: Graham Morrell, Paddock Circle Advisors,, Tel: +1 781 686 9600

Company Announcement no. 32 / 2023

[1] P. B. Gilbert et al., Science 10.1126/science.abm3425 (2021)

Published on August 31, 2023, 17:08 CET