Jaran Eriksen

In August 2024, multiple viral mpox outbreaks in Africa, uncontrolled spread of new strains, and ongoing global transmission among men who have sex with men (MSM) led WHO to declare a second global mpox emergency (PHEIC). Due to vaccine scarcity, Sweden followed EU recommendations for a dose-sparing intradermal (ID) vaccination regime, using one-fifth (0.1 ml) of the standard (0.5 ml) subcutaneous (SC) dose of the only approved vaccine, MVA-BN. Now, breakthrough infections in primary mpox-vaccinated MSM are rising, also in Sweden. Evidence of waning antibodies and lack of booster studies warrant this randomized clinical trial (RCT).We will conduct a phase 4, low-intervention RCT in 490 MSM who are primary mpox-vaccinated, randomizing them to an ID or SC booster or a control arm. Innovative methods will assess mucosal and serological immune responses (T-cells, binding/neutralizing antibodies) over two years, with noninferiority of ID vs. SC after one month as the primary endpoint. Safety is monitored. The study has regulatory and ethical approval in CTIS. Once funded it is ready to start within Venhälsan’s cohort of &gt

3800 primary vaccinated MSM at South General Hospital, Stockholm. This study answers pressing public health questions on booster effectiveness, particularly if the ID dose-sparing regime is non-inferior to standard care. Results will guide global recommendations and are urgent, given the need for MVA vaccine stockpiles for bioterror threats amid ongoing scarcity.

In August 2024, multiple viral mpox outbreaks in Africa, uncontrolled spread of new strains, and ongoing global transmission among men who have sex with men (MSM) led WHO to declare a second global mpox emergency (PHEIC). Due to vaccine scarcity, Sweden followed EU recommendations for a dose-sparing intradermal (ID) vaccination regime, using one-fifth (0.1 ml) of the standard (0.5 ml) subcutaneous (SC) dose of the only approved vaccine, MVA-BN. Now, breakthrough infections in primary mpox-vaccinated MSM are rising, also in Sweden. Evidence of waning antibodies and lack of booster studies warrant this randomized clinical trial (RCT).We will conduct a phase 3, low-intervention RCT in 490 MSM who are primary mpox-vaccinated, randomizing them to an ID or SC booster or a control arm. Innovative methods will assess mucosal and serological immune responses (T-cells, binding/neutralizing antibodies) over two years, with noninferiority of ID vs. SC after one month as the primary endpoint. Safety is monitored. The study has regulatory and ethical approval in CTIS. Once funded it is ready to start within Venhälsan’s cohort of &gt

3800 primary vaccinated MSM at South General Hospital, Stockholm. This study answers pressing global health questions on booster effectiveness, particularly if the ID dose-sparing regime is non-inferior to standard care. Results will guide global recommendations and are urgent, given the need for MVA vaccine stockpiles for bioterror threats amid ongoing scarcity.