Diabetes Affects Antibody Response to SARS-CoV-2 Vaccination in Older Residents of Long-term Care Facilities: Data From the GeroCovid Vax Study
Authors: Virgilio Enrico , Trevisan Caterina , Abbatecola Angela , Malara Alba , Palmieri Annapina , Fedele Giorgio , Stefanelli Paola , Leone Pasqualina , Schiavoni Ilaria , Maggi Stefania , Volpato Stefano , Antonelli Incalzi Raffaele , Onder Graziano ,   the GeroCovid Vax Working Group, Abbatecola Angela Marie , Andrieri Domenico , Incalzi Raffaele Antonelli , Arenare Francesca , Bagalà Viviana , Baldovin Tatjana , Bernardi Riccardo , Bianchi Alessandra , Bianchi Paola , Bisceglia Raffaella , Bissoli Ivan , Bontempi Fabio , Borselli Gilda , Bottaro Luigi , Bottoni Elisa , Brandi Silvia , Bravin Claudio , Buizza Maria Adele , Cafariello Carmine , Calabrese Alessia Maria , Calsolaro Valeria , Canepa Marta , Capasso Carla , Capuano Mariagrazia , Capurso Sebastiano , Carbone Gabriele , Carducci Marialudovica , Carino Silvia , Cattaneo Nicoletta , Ceravolo Francesco , Chiesara Maria Angelica Dorotea , Clerici Danila , Clerici Pierpaolo , Coin Alessandra , Collacchioni Vieri , Colombo Mauro , Compiano Michela , Costanza Giuseppina , Crupi Giovanna , Cucunato Roberta , D'Abramo Manuela Marina , D'Agostino Emilia , D'Amico Ferdinando , Simone Antonio De , Vecchio Stefania Del , Deleo Maria , Dell'Armi Annalaura , Brango Tommasina Di , Lonardo Anna Di , Nanno Maria Raffaella Di , Dijk Babette , Elmo Luisa , Fedele Giorgio , Ferraro Marisa , Ferro Christian , Fiorucci Claudia , Fortunato Francesca , Froncillo Pasquale , Galasso Domenico , Galdiero Nicola , Galdiero Caterina , Gallo Stefania , Gasbarri Pier Paolo , Gennai Maria Grazia , Ricci Giuliana Ghiselli , Giribaldi Elisa , Godeanu Carmen , Gommaraschi Samuele , Granata Roberta , Greco Giada Ida , Greco Angela , Grillo Antonio , Guerrini Gianbattista , Guglielmo Mauro , Haxhiaj Labjona , Iacovella Claudio Giuseppe , Indino Marina , Ippolito Valerio Alex , Kanah David , Kountsevich Liudmila , Leci Jovan , Limongi Federica , Lipari Agata , Longo Vincenzo , Maggi Stefania , Malara Alba , Maltese Leonarda , Marotta Maria , Mazzarella Giuseppe , Melnik Hior , Minchella Pasquale , Moneti Paolo , Monzani Fabio , Morandotti Walter , Morelli Francesco , Mortola Maria Grazia , Noale Marianna , Okoye Chukwuma , Onder Graziano , Orlanducci Patrizia , Paganelli Barbara , Pagano Michele , Pagano Nicola , Palladino Raffaele , Palmieri Annapina , Palumeri Magda , Paolini Simone , Paternò Raimondo , Pavan Angela , Pelucchi Loris , Perri Agostino , Perticone Francesco , Pesce Rosanna , Pigozzo Sabrina , Pili Francesco , Prato Rosa , Pullia Rosanna , Qasem Ahmad Amedeo , Addamo Francesco Raffaele , Raffaelli Cecilia , Restivo Vincenzo , Rigon Michela Fernanda , Romagnoni Franco , Romaniello Carmine , Romano Valentina , Ruberto Maria Cristina , Russo Marcello , Sala Bruno , Sambo Sara , Sciurti Maria Concetta , Scriva Antonietta , Secchi Luca , Settembrini Vincenzo , Sirianni Federica , Spaccaferro Deborah , Spadea Fausto , Stefanelli Manuela , Stefanelli Paola , Stelitano Brunella , Stringhini Stefania , Tarsitano Andrea , Terziotti Camilla , Trevisan Caterina , Ursino Rita , Veneziano Giovanni , Vigliotta Maria Teresa , Vignati Marco , Vignola Eva , Virgilio Enrico , Visconti Maria , Volpato Stefano , Vozzi Susanna , Zaccone Sabrina 
Published: October 2022

OBJECTIVE
Type 2 diabetes may affect the humoral immune response after vaccination, but data concerning coronavirus disease 19 (COVID-19) vaccines are scarce. We evaluated the impact of diabetes on antibody response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in older residents of long-term care facilities (LTCFs) and tested for differences according to antidiabetic treatment.

RESEARCH DESIGN AND METHODS
For this analysis, 555 older residents of LTCFs participating in the GeroCovid Vax study were included. SARS-CoV-2 trimeric S immunoglobulin G (anti-S IgG) concentrations using chemiluminescent assays were tested before the first dose and after 2 and 6 months. The impact of diabetes on anti-S IgG levels was evaluated using linear mixed models, which included the interaction between time and presence of diabetes. A second model also considered diabetes treatment: no insulin therapy (including dietary only or use of oral antidiabetic agents) and insulin therapy (alone or in combination with oral antidiabetic agents).

RESULTS
The mean age of the sample was 82.1 years, 68.1% were women, and 25.2% had diabetes. In linear mixed models, presence of diabetes was associated with lower anti-S IgG levels at 2 (β = −0.20; 95% CI −0.34, −0.06) and 6 months (β = −0.22; 95% CI −0.37, −0.07) after the first vaccine dose. Compared with those without diabetes, residents with diabetes not using insulin had lower IgG levels at 2- and 6-month assessments (β = −0.24; 95% CI −0.43, −0.05 and β = −0.30; 95% CI −0.50, −0.10, respectively), whereas no differences were observed for those using insulin.

CONCLUSIONS
Older residents of LTCFs with diabetes tended to have weaker antibody response to COVID-19 vaccination. Insulin treatment might buffer this effect and establish humoral immunity similar to that in individuals without diabetes.