Adverse reactions following mpox (monkeypox) vaccination

Until November 16th 2022 the Netherlands Pharmacovigilance Centre Lareb received 148 reports regarding adverse drug reactions after mpox vaccination. A total of 2205 reports were received in the global database of the WHO in 2022. Injection site reactions and general systemic reactions were the most commonly reported adverse events in both databases.  

In 2022, the spreading of mpox (formally known as monkeypox) virus led to a vaccination campaign in the Netherlands for individuals at high risk of infection. This was the first vaccination campaign for mpox in the Netherlands. Approximately 13.000 individuals had been vaccinated by 29 September 2022, of whom 5000 also received a second vaccination. The vaccine Imvanex is used in Europe for immunization against mpox. The vaccine is registered in the United States as Jynneos.

Reports at Lareb and the Global Database
Of the reports received at Lareb two persons reported a serious outcome of their reaction (1.4%). In the global database of the World Health Organization 2205 reports were received on Imvanex and Jynneos in 2022, of which 131 reports (5.9%) concerned a serious reaction.

Pattern of reported adverse reactions
The pattern of reported adverse reactions for mpox vaccines both in the Dutch and global database is generally in accordance with the manufacturer's product information and consists largely of injection site reactions and nonserious adverse events related to systemic reactogenicity.

Read the full paper in the British Journal of Clinical Pharmacology here.