Background: In Asia, COVID-19 vaccine hesistancy among solid organ transplant recipients has been reported to be as high as 77.2%. There is lack of data addressing the side effect profile of mRNA vaccine in Asian transplant recipients which is important, given that reassuring data may reduce vaccine hesistancy. As a result, this study compares the spectrum of side effects observed with 2 doses of mRNA vaccine in kidney transplant recipients (KTX) and healthcare providers (HP) from the Department of Renal Medicine at the Singapore General Hospital.

Methods: A cross-sectional survey was conducted via an online questionnaire for a period of 3 months. The questionnaire collected data on demographics, previous vaccine uptake history, type of vaccine received, side effects observed and post-vaccination sequelae like outpatient/inpatient medical attendances and COVID-19 infection.

Results: The study population consisted of 124 KTX and 96 HP, all receiving 2 doses of mRNA COVID-19 vaccine but more HP than KTX had received their vaccine more than 2 months ago (89.6% vs. 67.7%; p<0.005). The proportion of KTX and HP experiencing side effects from their 1st dose was similar (77.4% and 84.4% respectfully; p=0.197) but the proportion of KTX experiencing side effects from their 2nd dose was lower than compared to HP (75%; vs. 89.6%; p=0.006). For the first dose and second dose, the number of side effects reported was also lower among KTX compared to HP (1.44±1.42 vs. 2.31±2.0; p<0.005 for the 1st dose and 1.38±1.33 vs. 2.91±2.4; p<0.005 for the 2nd dose) and more KTX reported no or mild side effects compared to HP (89.4% vs. 79.1%; p<0.005 for the 1st dose and 92.3% vs. 65.6% for the 2nd dose; p<0.005). Compared to HP, less KTX experienced swelling (9.7% vs. 28.1%; p<0.005 for 1st dose and 8.1% vs. 33.3%; p<0.005 for 2nd dose), injection site redness (3.2% vs. 10.4%; p=0.03 for 1st dose and 2.4% vs. 10.4%; p=0.031 for 2nd dose), body ache (15.3% vs. 32.3%; p<0.005 for 1st dose and 14.5% vs. 38.5%; p<0.005 for 2nd dose), chills (0.8% vs. 8.3%; p=0.005 for 1st dose and 4.8% vs. 16.7%; p=0.011 for 2nd dose) and headache (6.5% vs. 14.6%; n=0.046 for 1st dose and 7.3% vs. 20.8%; p<0.005 for 2nd dose).  In addition for the 2nd dose, less KTX experienced fever (7.3% vs. 27.1%; p<0.005), giddiness (0.8% vs 7.3%; p=0.027) and arthralgia (1.6% vs. 8.3%; p=0.042).  A lower proportion of KTX compared to HP also needed to see a doctor following vaccination (2.4% vs. 6.3%; p<0.005 for the 1st dose and 1.6% vs. 14.5%; p<0.005). There were 2 cases of post-vaccination Bell Palsy among KTX and 1 KTX suffered rejection after 2 dose of vaccine.

Conclusion: Contrary to patients’ perceptions, side effects from COVID-19 mRNA vaccine are none or mild in the majority of KTX receiving these vaccines.  Serious side effects like Bell Palsy and rejection were rare. Interestingly, side effects were less common among KTX than HP, presumably because immunosuppression blunted the side effects in KTX.