Bavarian Nordic’s (OTCPK:BVNKF) European listed shares were down around 7% Thursday morning, the day after a published study showed that a mpox vaccine being developed by Moderna (NASDAQ:MRNA) appeared to be more effective in preventing severe disease than Bavarian’s mpox vaccine Jynneos.

The study, which was published online in the scientific journal Cell, evaluated Moderna’s mpox vaccine candidate mRNA-1769 and Jynneos in non-human primates. Results showed that while both vaccines were able to prevent death from the disease, primates that were given mRNA-1769 developed fewer lesions and other serious symptoms.

Demand for vaccines that can protect against mpox, also known as monkeypox, has dramatically increased in recent weeks due to a prolonged outbreak in Africa. Other companies working on vaccines or treatments for the disease include Emergent BioSolutions (EBS), Chimerix (CMRX), Aspen Pharmacare (OTCPK:APNHF), GeoVax Labs (GOVX), SIGA Technologies (SIGA) and Tonix Pharmaceuticals (TNXP).

Companies making tests for the disease include Co-Diagnostics (CODX), Roche (OTCQX:RHHBY) (OTCQX:RHHBF), Abbott Laboratories (ABT) and Applied DNA Sciences (APDN).