We would like to comment on the recent article in Diabetes by D’Addio et al. (1). The authors linked administration of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine to a reduced cellular SARS-CoV-2–specific cytotoxic immune response in patients with type 1 diabetes (1). We agree that people with type 1 diabetes can have a wide range of antibody responses. This study can provide some evidence in this regard. However, it is critical to keep in mind the possibility that confounding factors influencing the immunological parameters are being measured. Infection with coronavirus disease 2019 (COVID-19) without symptoms is not uncommon (2). There is a chance of asymptomatic COVID-19 after immunization, which could make interpreting immunological markers challenging. It is important to rule out the potential for asymptomatic COVID-19.

See accompanying article, p. e14.

Duality of Interest. No potential conflicts of interest relevant to this article were reported.

1.
D’Addio
F
,
Sabiu
G
,
Usuelli
V
, et al
.
Immunogenicity and safety of SARS-CoV-2 mRNA vaccines in a cohort of patients with type 1 diabetes
.
Diabetes
2022
;
71
:
1800
1806
2.
Joob
B
,
Wiwanitkit
V
.
Letter to the editor: coronavirus disease 2019 (COVID-19), infectivity, and the incubation period
.
J Prev Med Public Health
2020
;
53
:
70
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