Dear Editor:

We would like to comment on the article from Drs. Ishida and colleagues, titled “Antibody response to SARS-CoV-2 mRNA vaccine among kidney transplant recipients: a retrospective cohort study at a single transplant institute in Japan.”¹ Ishida and colleagues found that the percentage of responsive viral fragments varied substantially between patients and showed no consistency in the kidney transplant group, whereas the mean fluorescence intensity of individual fragments showed a trend in the control group.¹

We agree that a kidney transplant recipient’s immune response may differ from that of a healthy person. Although their study may provide important information, it should also take into account the possibility of a confounding underlying element. Because of immunologic anomalies, COVID-19 may become asymptomatic, making it more difficult to establish the vaccine’s efficacy in prior trials. In general, asymptomatic COVID-19 is not uncommon.² The possibility of asymptomatic COVID-19 must be ruled out before a firm judgment can be reached.³ Whether COVID-19 presents as asymptomatic or symptomatic, immunization can establish immunity, although asymptomatic infection can dramatically affect the measured immunologic status.

References:

1. Ishida H, Furusawa M, Unagami K, Omoto K, Iizuka J, Takagi T. Antibody response to SARS-CoV-2 mRNA vaccine among kidney transplant recipients: a retrospective cohort study at a single transplant institute in Japan. Exp Clin Transplant. 2022;20(5):463-471. doi:10.6002/ect.2022.0020
   Crossref-PubMed
   
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(2):70. doi:10.3961/jpmph.20.065
   Crossref-PubMed
   
3. Mungmunpuntipantip R, Wiwanitkit V. CoronaVac or BNT162b2 vaccine as a third dose. Am J Respir Crit Care Med. 2022;206(3):360-361. doi:10.1164/rccm.202201-0077LE
   Crossref -PubMed