TY - JOUR
T1 - Antibody Responses are Sustained 2 Years Post-Mpox Infection but not Following Modified Vaccinia Ankara–Bavarian Nordic Vaccination
AU - On behalf of the All Ireland Infectious Diseases Cohort Study
AU - Byrne, Joanne
AU - Garcia-Leon, Alejandro
AU - Murphy, Aisling
AU - Saini, Gurvin
AU - Banik, Ishan
AU - Landay, Alan
AU - Nguyen, Liem Binh Luong
AU - Savinelli, Stefano
AU - O’Broin, Cathal
AU - Horgan, Mary
AU - Kelly, Christine
AU - Mejia-Chew, Carlos
AU - Sadlier, Corinna
AU - de Barra, Eoghan
AU - O’Halloran, Jane A.
AU - Gautier, Virginie
AU - Mallon, Patrick W.G.
AU - Feeney, Eoin R.
N1 - Publisher Copyright:
© The Author(s) 2025. Published by Oxford University Press on behalf of Infectious Diseases Society of America.
PY - 2025/9/1
Y1 - 2025/9/1
N2 - Background. Clade IIb mpox cases have declined globally, likely due to behavioral changes alongside vaccine- and infection-induced immunity. However, infections in vaccinated individuals raise concerns about immunity durability. We compared the longevity of antibody responses following mpox infection and modified vaccinia Ankara–Bavarian Nordic (MVA–BN) vaccination. Methods. In a multicenter, prospective cohort, we measured plasma IgG titers to vaccinia virus (VACV) B5 antigen in adults with prior mpox, MVA–BN vaccination, and historical controls, sampled up to 2 years postexposure. Receiver operating characteristic analysis determined the seropositivity threshold. Generalized additive mixed models compared antibody kinetics, and logistic regression identified factors associated with seropositivity. The results are median (interquartile range) unless specified. Results. A total of 122 vaccinated participants (100% male, aged 36 [32.5–43.5], 25% people with HIV [PWH]) were sampled at 22.0 (20.0–23.5) months post-MVA–BN vaccination, 72 of whom had a paired sample 12.5 (8.0–15.5) months prior, alongside 13 participants post-mpox (100% male, aged 32.5 [30.5–40], 23% PWH) sampled 25.0 (22.5–29.0) months postinfection, 12 with a paired sample 12.5 (8.5–15.5) months prior. At follow-up, 85% (11/13) of the post-mpox group remained seropositive, versus 32% (39/122) of the vaccinated group. Predicted geometric-mean anti-VACV-B5 titers fell below the seropositivity threshold at 15.5 (95% confidence interval [CI]: 13.0–19.5) months postvaccine. PWH had significantly lower odds of retaining seropositivity (odds ratio: 0.18; 95% CI: .04–.60; P = .01). Conclusions. Antibody titers declined more rapidly postvaccination than post-mpox, with most vaccinated recipients, particularly PWH, losing seropositivity at 2 years. How these data relate to reinfection risk or the need for boosters remains to be determined.
AB - Background. Clade IIb mpox cases have declined globally, likely due to behavioral changes alongside vaccine- and infection-induced immunity. However, infections in vaccinated individuals raise concerns about immunity durability. We compared the longevity of antibody responses following mpox infection and modified vaccinia Ankara–Bavarian Nordic (MVA–BN) vaccination. Methods. In a multicenter, prospective cohort, we measured plasma IgG titers to vaccinia virus (VACV) B5 antigen in adults with prior mpox, MVA–BN vaccination, and historical controls, sampled up to 2 years postexposure. Receiver operating characteristic analysis determined the seropositivity threshold. Generalized additive mixed models compared antibody kinetics, and logistic regression identified factors associated with seropositivity. The results are median (interquartile range) unless specified. Results. A total of 122 vaccinated participants (100% male, aged 36 [32.5–43.5], 25% people with HIV [PWH]) were sampled at 22.0 (20.0–23.5) months post-MVA–BN vaccination, 72 of whom had a paired sample 12.5 (8.0–15.5) months prior, alongside 13 participants post-mpox (100% male, aged 32.5 [30.5–40], 23% PWH) sampled 25.0 (22.5–29.0) months postinfection, 12 with a paired sample 12.5 (8.5–15.5) months prior. At follow-up, 85% (11/13) of the post-mpox group remained seropositive, versus 32% (39/122) of the vaccinated group. Predicted geometric-mean anti-VACV-B5 titers fell below the seropositivity threshold at 15.5 (95% confidence interval [CI]: 13.0–19.5) months postvaccine. PWH had significantly lower odds of retaining seropositivity (odds ratio: 0.18; 95% CI: .04–.60; P = .01). Conclusions. Antibody titers declined more rapidly postvaccination than post-mpox, with most vaccinated recipients, particularly PWH, losing seropositivity at 2 years. How these data relate to reinfection risk or the need for boosters remains to be determined.
KW - MVA–BN vaccine
KW - Mpox
KW - antibodies
KW - immune responses
KW - monkeypox virus
UR - https://www.scopus.com/pages/publications/105016730256
UR - https://www.scopus.com/inward/citedby.url?scp=105016730256&partnerID=8YFLogxK
U2 - 10.1093/ofid/ofaf536
DO - 10.1093/ofid/ofaf536
M3 - Article
C2 - 41018709
AN - SCOPUS:105016730256
SN - 2328-8957
VL - 12
JO - Open Forum Infectious Diseases
JF - Open Forum Infectious Diseases
IS - 9
M1 - ofaf536
ER -