Protection against severe COVID-19 after second booster dose of adapted bivalent (original/Omicron BA.4-5) mRNA vaccine in persons ≥ 60 years, by time since infection, Italy, 12 September to 11 December 2022

Fabiani, M.; Mateo-Urdiales, A.; Sacco, C.; Fotakis, E. A.; Rota, M. C.; Petrone, D.; Bressi, M.; Del Manso, M.; Siddu, A.; Fedele, G.; Stefanelli, P.; Bella, A.; Riccardo, F.; Palamara, A. T.; Rezza, G.; Brusaferro, S.; Pezzotti, P.; Boros, S.; Ceccarelli, E.; D'Ancona, F. P.; Di Benedetto, C.; Filia, A.; Urdiales, A. M.; Tallon, M.; Vescio, M. F.; Petrucci, A.; La Bianca, M.; Mignuoli, A. D.; Buono, P.; Massimiliani, E.; Barbone, F.; Vairo, F.; Sticchi, C.; Cereda, D.; Pompili, M.; Sforza, F.; Bertoli, P.; Benetollo, P. P.; Pasqualini, C.; Bisceglia, L.; Palmas, M. A.; Addario, S. P.; Balocchini, E.; Tosti, A.; Ruffier, M.; Da Re, F.; Battilomo, S.; Proietti, V.; Odio, C.; Recine, M.; Ruberto, I.; Ascione E Massimo Bisogno, S.; Miserendino, G.; Navacchia, M.; Del Frate, B.; Cau, E.; Baiocchi, D.; Fusco, D.; Gallo, D.; Marchetti, M. R.; Spazzafumo, L.; Malatesta, R.; Fanolla, A.; Conforti, D.; Trentini, C.; Ruggeri, A.; Ladalardo, C.; Albano, N.; Corona, M.; Lombardi, P.; Iacono, M.; Angori, P. B.; Belardinelli, A.; Solfiti, M.; Fioraso, S.; Poma, C.; Raccanello, N.

doi:10.2807/1560-7917.ES.2023.28.8.2300105

Effectiveness against severe COVID-19 of a second booster dose of the bivalent (original/BA.4-5) mRNA vaccine 7-90 days post-administration, relative to a first booster dose of an mRNA vaccine received ≥ 120 days earlier, was ca 60% both in persons ≥ 60 years never infected and in those infected > 6 months before. Relative effectiveness in those infected 4-6 months earlier indicated no significant additional protection (10%; 95% CI: -44 to 44). A second booster vaccination 6 months after the latest infection may be warranted.

Protection against severe COVID-19 after second booster dose of adapted bivalent (original/Omicron BA.4-5) mRNA vaccine in persons ≥ 60 years, by time since infection, Italy, 12 September to 11 December 2022 / Fabiani, M., Mateo-Urdiales, A., Sacco, C., Fotakis, E.A., Rota, M.C., Petrone, D., Bressi, M., Del Manso, M., Siddu, A., Fedele, G., Stefanelli, P., Bella, A., Riccardo, F., Palamara, A.T., Rezza, G., Brusaferro, S., Pezzotti, P., Boros, S., Ceccarelli, E., D'Ancona, F.P., et al.. - In: EUROSURVEILLANCE. - ISSN 1025-496X. - 28:8(2023). [10.2807/1560-7917.ES.2023.28.8.2300105]