RNDr. Ondřej Hajdušek, Ph.D.
Job Position: Research Scientist - Laboratory of Molecular Biology of Ticks
Phone:
+420 387775496
E-mail:
hajdus@paru.cas.cz
Room:
337
Research interests
- Vaccines against ticks and tick-transmitted diseases
- Tick innate immunity
Key words: tick, Ixodes, Borrelia, Babesia, Anaplasma, iron, ferritin, innate immunity, vaccine
Education:
- Bachelor program - University of South Bohemia in České Budějovice, Faculty of Biological Sciences, Czech Republic (Biology; Biomedicine laboratory technique)
- Masters program - University of South Bohemia in České Budějovice, Faculty of Biological Sciences, Czech Republic (Parasitology)
- Ph.D. program (graduated 2009) - University of South Bohemia in České Budějovice, Faculty of Science, Czech Republic (Parasitology)
- Postdoctoral research - Institut de Biologie Moléculaire et Cellulaire (IBMC), CNRS UPR 9022 (Réponse immunitaire et développement chez les Insectes), Strasbourg, France (3 years)
Science visits:
- 1998 - PHLS London (UK)
- 2001 - University of Glasgow (UK)
- 2005 - National Research Council of Canada, Ottawa (CAN)
- 2006 - Centre National de la Recherche Scientifique, Strasbourg (FRA)
Awards:
- 2009 - Dean´s award - University of South Bohemia in České Budějovice, Faculty of Biological Sciences, Czech Republic
- 2009 - Rector´s award - University of South Bohemia in České Budějovice, Faculty of Biological Sciences, Czech Republic
- 2009 - Scopus Young Researcher Award, Czech Republic
Grants:
- 2010-2012 - EMBO Long Term Fellowship
- 2013-2015 - Grant agency of the Czech Republic (GACR) - 13-27630P
- 2013-2015 - MODBIOLIN, 7FP, GA No. 316304
- 2014-2018 - ANTIDotE, 7FP EU
- 2016-2019 - Grant agency of the Czech Republic (GACR) - 17-27386S
- 2018-2022 - Ministry of Education, Youth and Sport of the Czech Republic (MSMT) - CZ.02.1.01/0.0/0.0/16_019/0000759
- 2025-2028 - Ministry of Education, Youth and Sport of the Czech Republic (MSMT) - CZ.02.01.01/00/23_020/0008499
- 2025-2027 - Grant agency of the Czech Republic (GACR) - 25-16064S
.jpg)
České Budějovice, April 25, 2025
A new and safe human vaccine against Lyme borreliosis on the horizon
Lyme borreliosis (disease) is a serious bacterial infection affecting both humans and animals. It is caused by the bacterium Borrelia burgdorferi, which is transmitted to humans by infected ticks of the genus Ixodes. In the Czech Republic, the main vector is the castor bean tick (Ixodes ricinus). The disease occurs exclusively in the Northern Hemisphere, mainly in wealthier countries such as the United States and most of Europe. The manifestations of Lyme borreliosis can vary widely, from fever and skin involvement to nervous system complications and even heart inflammation. One of the earliest symptoms is a red skin lesion known as erythema migrans, which appears approximately one to two weeks after infection. It typically develops at the site of the tick bite and gradually enlarges. Unfortunately, it appears in only about half of the cases. For those who develop it, this rash is fortunate, as it serves as a clear signal for physicians and enables early antibiotic treatment, which is usually very effective. However, if the infection is not recognized in time and progresses to an advanced stage, treatment becomes more complicated and less effective. Blood tests detecting antibodies against Borrelia are used to confirm the diagnosis, but because antibodies develop gradually, the timing of the testing is critical.
Currently, no human vaccine against Lyme borreliosis is available, despite significant demand. Lyme borreliosis remains a common and burdensome illness with the potential for serious health impacts. Nevertheless, a commercial vaccine for humans did exist in the past. In 1998, the vaccine LYMErix was approved and launched in the United States. It demonstrated reasonable efficacy but soon faced criticism over possible, though never conclusively proven, side effects. Following several lawsuits, negative media attention, and declining sales, the manufacturer voluntarily withdrew LYMErix from the market in 2002. It is important to recognize that vaccines are typically developed by private companies rather than governments, and they are primarily driven by economic interests. Nevertheless, after more than twenty years, hope has re-emerged. The pharmaceutical companies Valneva and Pfizer are jointly developing a new Lyme borreliosis vaccine called VLA15. This vaccine is currently undergoing Phase III clinical trials in both the United States and Europe, where its safety and efficacy are being evaluated. Ten thousand participants from areas with high Lyme borreliosis incidence have been enrolled in the study. Half of them received the vaccine, and the other half received a placebo. Researchers are now monitoring how many participants actually develop Lyme borreliosis. The results of this study are expected by the end of 2025. If the vaccine proves effective and safe, the manufacturers may apply for approval for production and sale. In the best-case scenario, the vaccine could reach the market as early as 2026, including in the Czech Republic.
All past and current Lyme borreliosis vaccines are based on immunization against Borrelia's outer surface protein A (OspA). Because the structure of this protein varies among different Borrelia species capable of infecting humans, the current vaccines include multiple OspA variants to ensure global coverage. Furthermore, today's vaccines have been designed to exclude the problematic part of the protein that was associated with controversies during the use of LYMErix. However, a major challenge lies in the biology of Borrelia, ticks, and humans. This is something we cannot influence, but it is necessary to study all these biological relationships in detail in order to improve vaccine design in the future. The OspA protein is present on the surface of Borrelia only when the bacterium resides inside the tick. Once Borrelia begins transmission to a human, OspA production stops completely. As a result, antibodies circulating in the human body lose their target and are no longer able to eliminate the bacteria effectively. The vaccine is unique in that it relies on human antibodies, induced by vaccination, entering the tick’s gut with the blood meal. There, the antibodies bind to Borrelia and prevent its transmission to the human host. This inhibition within the tick is highly effective but decreases as the antibody levels in the bloodstream decline. If antibody levels fall below a protective threshold within six to twelve months after vaccination, the vaccine no longer provides protection, and even vaccinated individuals can become infected. This unique mechanism of vaccine action thus also represents its major weakness. Consequently, it points toward the need for annual vaccination, ideally administered just before the start of the tick season in spring, which may understandably be unpopular for many people. The vaccine is intended for individuals aged five years and older. However, it remains uncertain how many people will be willing to undergo such frequent vaccinations, and whether the cost of the vaccine will represent an obstacle for most of the population. Unfortunately, even against tick-borne encephalitis, despite it being a highly effective, well-tested, and widely promoted vaccine, only about 20% of the Czech population is currently vaccinated.
I am proud that Czech science is making a significant contribution to the development, refinement, and testing of Lyme borreliosis vaccines. At the Institute of Parasitology of the Biology Centre of the Czech Academy of Sciences in České Budějovice, several research groups have long been engaged in both fundamental and applied research on the physiology of ticks and Borrelia bacteria. In our Laboratory of Molecular Biology of Ticks, we are working to understand in detail how antibodies directed against the OspA surface protein inhibit Borrelia directly within the tick before transmission to the human host. In addition, we are improving existing vaccination strategies to induce higher and more stable antibody responses. In collaboration with leading pharmaceutical companies such as Sanofi, as well as the Czech company Contipro based in Dolní Dobrouč, we are testing new vaccination approaches using unique experimental models that we have developed. Our long-term goal is to offer the public alternative vaccination forms, such as nasal sprays, tablets, or skin patches, which could provide more convenient and accessible alternatives to traditional needle-based vaccines.
RNDr. Ondřej Hajdušek, Ph.D.
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(23)00312-2/fulltext
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00160-4/fulltext?rss=yes
