Background: Thrombo-embolic events (TEE) after Coronavirus disease-19 (COVID-19) vaccination have been reported previously from other countries. Patients admitted with TEE to our hospital during the initial 3 months of vaccination drive in India were studied.
Method and Results: All patients who were admitted to our hospital between 1st March 2021 and 31st May 2021 (inclusive) with evidence of thrombosis in imaging study or coronary angiography were analysed. A detailed vaccination history including the type, dose and date of vaccine were obtained from the patients/attenders. The baseline characteristics of these patients were collected and detailed analysis were done to correlate the timing of vaccination and the current episode of TEE. Categorical variables are expressed as numbers and percentages and normally distributed continuous variables are expressed as mean ± SD, unless mentioned otherwise. Comparison between two groups was performed using Fisher’s Exact test for categorical variables and the paired two-tailed ‘t’ test for normally distributed variables.Of the 163 patients (Age 55±14 y, 34 f) admitted, 48 (29.5%) had vaccination history within 1 month of index event. The time interval between vaccination and TEE was <1, 1-2, and 2 weeks to 1 month in 17 (35%), 10 (21%), and 21 (44%) patients respectively. ChAdOx1 nCoV-19/AZD1222 was the most used vaccine- 35(73%), while 13(27%) had Covaxin. Baseline characteristics were similar in patients who were vaccinated within one month (Group 1) and others (Group 2, n=115). Thrombus location was similar in both groups [Coronary (60%vs52%, p=0.39), Cerebro-vascular (23%vs24% p=1), peripheral artery (4%vs5%, p=1), deep vein thrombosis (DVT)/pulmonary embolism (PE) (13%vs16%, p=0.81), central vein (0vs3%, p= 0.53- Group 1 vs Group 2 respectively]. The In-hospital mortality rate was 4.2% and 3.5% (p= 1.0) respectively. There were higher rates of DVT/PE after Covaxin administration (4/13, 31%) compared to Covishield (2/35, 5%, p=0.04).
Conclusion: This single centre study showed that 29.5% of patients admitted in the first 3 months of vaccination with TEE had at least one dose of COVID-19 vaccine within one month prior to the index event. Both types of vaccine (Covishield and Covaxin) were associated with TEE. We need further studies to identify the incidence of this rare, but serious adverse events following COVID-19 vaccination.
TABLE. Baseline Characteristics of patients
| Age in years | 55±14 | 58±11 | 54±14 | 0.08 |
| Male | 129 (79) | 37 (77) | 92 (80) | 0.68 |
| Diabetes | 102 (63) | 31 (65) | 71 (62) | 0.86 |
| Hypertension | 81 (50) | 26 (54) | 55 (48) | 0.50 |
| Dyslipidemia | 78 (48) | 27 (56) | 51 (44) | 0.17 |
| Smoker | 5 (3) | 1 (2) | 4 (4) | 1.0 |
| Previous CAD/CVA | 23 (14) | 7 (15) | 16 (14) | 1.0 |
| Previous COVID-19 infection | 20 (12) | 4 (8) | 16 (14) | 0.44 |
| Renal impairment (e GFR<60/ml/min/1.73m2) | 16 (10) | 3 (6) | 13 (11) | 0.40 |
| Platelet count (x 103/ml) | 284±109 | 284±102 | 284±113 | 0.99 |
| Thrombocytopenia (<150 x 103/ ml) | 13 (8) | 2 (4) | 11 (10) | 0.35 |
| Thrombus location | ||||
| Coronary | 89 (55) | 29 (60) | 60 (52) | 0.39 |
| Cerebro-vascular | 38 (23) | 11 (23) | 27 (24) | 1.0 |
| Peripheral artery | 8 (5) | 2 (4) | 6 (5) | 1.0 |
| DVT/PE | 24 (15) | 6 (13) | 18 (16) | 0.81 |
| Central Vein | 3 (2) | 0 | 3 (3) | 0.56 |
| Other venous | 1 (1) | 0 | 1 (1) | 1.0 |
ABCSI21172