Pneumonic Plague Tracker

Vaccines

What exists, what does not, and what is in trials

1. None licensed

   Is there a licensed plague vaccine?

   Not in the United States or the European Union. No plague vaccine is approved by the FDA for human use. Live attenuated vaccines based on the EV76 strain have been used for decades in high-risk groups in Russia, the former Soviet states, China and Mongolia, and are not licensed in Western countries.

   [3] [5]

2. Restricted

   Does WHO recommend vaccination?

   No, except for high-risk groups. WHO's position is that it “does not recommend vaccination, except for high-risk groups” such as laboratory personnel and health workers with constant exposure. That exception is the category the Irkutsk worker fell into.

   [1]

3. Works today

   What is given to contacts instead?

   Antibiotics, not a vaccine. WHO recommends seven days of chemoprophylaxis for health workers in direct contact with pneumonic patients, for close contacts of pneumonic cases, and for household members of bubonic cases.

   [1]

4. In trials

   Why has no subunit vaccine been licensed?

   The lead candidate is rF1V, a recombinant fusion of the F1 capsular antigen and the V antigen with an aluminium hydroxide adjuvant. It has gone through clinical trials but is not licensed. Plague is too rare for an efficacy trial in humans, so approval would have to rest on animal data plus human immunogenicity, which is the central regulatory obstacle.

   [3] [5]

5. Restricted

   Why is the live vaccine not used in the West?

   EV76 is attenuated rather than inert. It causes significant reactions in a proportion of recipients, and carries a theoretical risk of reverting toward virulence, so Western regulators have not adopted it. Work continues on safer derivatives: a 2024 paper reports a modified EV76 strain with improved safety and protection in animal models.

   [5] [4]

6. Unproven

   Would a vaccine have protected against pneumonic plague?

   Not reliably, on current evidence. Protection against the pneumonic form is harder than against the bubonic form, and demonstrating it is the main unsolved problem in the field. This matters directly here: the Irkutsk case is a suspected pneumonic exposure in exactly the occupational group a vaccine would target.

   [2] [3]

7. Experimental

   What is the Israeli mRNA vaccine?

   The first mRNA vaccine shown to work against a bacterium. A team at Tel Aviv University with the Israel Institute for Biological Research solved the problem that had blocked mRNA vaccines for bacteria: bacteria make their own proteins, so a bacterial gene delivered to human cells produces a protein the immune system does not recognise. They re-engineered the sequence so human cells make it in a recognisable form. The 2023 paper reports a single-dose F1-based mRNA-LNP vaccine protecting mice against lethal plague.

   [6]

8. Experimental

   How well does it work, and where is it up to?

   In mice, very well. The 2025 follow-up is bivalent, carrying both F1 and LcrV, and reports 100 percent survival across three mouse strains on a three-dose course, and 75 to 100 percent on two doses. It protected against two virulent biovars and against an F1-negative strain, which matters because losing F1 is a known way the bacterium evades F1-only vaccines. Its own words: the vaccine “conferred robust protection against severe bacterial pneumonia in multiple mouse strains challenged with two different Y. pestis biovars”.

   [7]

9. Not available

   Could it have helped in Irkutsk?

   No. It has never been tested in humans. Both papers are mouse studies and the 2025 one calls for “future translational studies”, which is the phrase for human trials that have not started. It is the most promising thing in this field and it is still years from anyone’s arm, so it was not an option for a laboratory worker in September 2026.

   [7] [6]

Sources

1. Authority World Health Organization. (2022). Plague [Fact sheet]. https://www.who.int/news-room/fact-sheets/detail/plague
2. Peer-reviewed Feodorova, V.A., & Motin, V.L. (2012). Plague vaccines: current developments and future perspectives. Emerging Microbes & Infections, 1(1), 1-5. https://doi.org/10.1038/emi.2012.34
3. Peer-reviewed Sun, W., & Singh, A.K. (2019). Plague vaccine: recent progress and prospects. npj Vaccines, 4(1). https://doi.org/10.1038/s41541-019-0105-9
4. Peer-reviewed Guo, X., Xin, Y., Tong, Z., Cao, S., Zhang, Y., Wu, G., Chen, H., Wang, T., Song, Y., Zhang, Q., Yang, R., & Du, Z. (2024). A novel sORF gene mutant strain of Yersinia pestis vaccine EV76 offers enhanced safety and improved protection against plague. PLOS Pathogens, 20(3), e1012129. https://doi.org/10.1371/journal.ppat.1012129
5. Peer-reviewed Rosario-Acevedo, R., Biryukov, S.S., Bozue, J.A., & Cote, C.K. (2021). Plague Prevention and Therapy: Perspectives on Current and Future Strategies. Biomedicines, 9(10), 1421. https://doi.org/10.3390/biomedicines9101421
6. Peer-reviewed Kon, E., Levy, Y., Elia, U., Cohen, H., Hazan-Halevy, I., Aftalion, M., Ezra, A., Bar-Haim, E., Naidu, G.S., Diesendruck, Y., Rotem, S., Ad-El, N., Goldsmith, M., Mamroud, E., Peer, D., & Cohen, O. (2023). A single-dose F1-based mRNA-LNP vaccine provides protection against the lethal plague bacterium. Science Advances, 9(10). https://doi.org/10.1126/sciadv.adg1036
7. Peer-reviewed Elia, U., Levy, Y., Cohen, H., Zauberman, A., Gur, D., Hazan-Halevy, I., Aftalion, M., Benarroch, S., Bar-Haim, E., Redy-Keisar, O., Cohen, O., Peer, D., & Mamroud, E. (2025). Novel Bivalent mRNA-LNP Vaccine for Highly Effective Protection against Pneumonic Plague. Advanced Science, 12(26). https://doi.org/10.1002/advs.202501286

Compiled 6 October 2026. Every DOI on this page was checked against the Crossref API rather than merely clicked, which is what proves a DOI points at the paper it claims to. Nothing here is medical advice.