Erythema and Induration after Mpox (JYNNEOS) Vaccination Revisited

This correspondence reanalyzes data from a randomized trial comparing subcutaneous versus intradermal administration of the MVA-BN (JYNNEOS) vaccine, using the updated FDA Toxicity Grading Scale. Among 358 participants, the intradermal route authorized during the 2022 mpox outbreak for dose-sparing showed a higher incidence of moderate or severe erythema after the second dose (59.5%) compared to subcutaneous administration (31.2%), but erythema duration was shorter (median 2 vs. 3 days). Induration rates were similar across groups. Reactogenicity was deemed acceptable, with intradermal administration allowing for 80% dose sparing and potentially broader access. The analysis supports continued use of the intradermal route for mpox prophylaxis.

This correspondence reanalyzes data from a randomized trial comparing subcutaneous versus intradermal administration of the MVA-BN (JYNNEOS) vaccine, using the updated FDA Toxicity Grading Scale. Among 358 participants, the intradermal route authorized during the 2022 mpox outbreak for dose-sparing showed a higher incidence of moderate or severe erythema after the second dose (59.5%) compared to subcutaneous administration (31.2%), but erythema duration was shorter (median 2 vs. 3 days). Induration rates were similar across groups. Reactogenicity was deemed acceptable, with intradermal administration allowing for 80% dose sparing and potentially broader access. The analysis supports continued use of the intradermal route for mpox prophylaxis.