ABSTRACT
(i) Background: ChAdOx1 nCoV-19 (Covishield®) vaccine is widely used in India. We studied the Covishield® induced antibody response and its durability among health care workers (HCWs) (ii) Method: HCWs received two doses (0.5 mL) four weeks apart. Blood specimens, collected before each dose, day (D)60, D150 and D270 after second dose, were tested for anti-spike antibody (ASAb) titre and neutralising antibody (%) (NAb) using Elecsys Anti-SARS-CoV-2 S (Roche) and SARS-CoV-2 NAb ELISA Kit (Invitrogen), respectively. Data are expressed as proportions and median (interquartile range) and compared using non-parametric (iii) Result: Among 135 HCWs (83 males; age 45 (37−53); 36 had pre-existing ASAb), 29 (21.5%) acquired COVID-19 after 60 (39−68) days of vaccination. ASAb titre before second dose and at D60, D150, D270 were 77.2 (19.4−329.4), 512 (114.5−9212), 149 (51.6−2283) and 2079 (433.9−8644) U/mL, respectively. Compared to those without pre-existing ASAb, titres were significantly higher before second dose (5929 vs. 41, p < 0.001), D60 (3395 vs. 234, p = 0.007) and D150 (1805 vs. 103, p < 0.001) in participants with pre-existing ASAb; NAb were also higher (80 vs. 18, p < 0.001) before second dose. Between those who acquired infection or not after vaccination, ASAb titres were comparable before second dose (77 vs. 78, p = 0.362) but significantly higher at D60 (14,019 vs. 317, p < 0.001) and D150 (2062 vs. 121, p = 0.002) in the former group, though NAb percentage were higher at D60 (87 vs. 27, p < 0.001) and D150 (79 vs. 25, p = 0.007) only (iv) Conclusions: Covishield® induces a higher antibody titre in those with pre-existing ASAb. The vaccine induced antibody starts falling 5 months after vaccination.
ABSTRACT
INTRODUCTION: Data are limited on antibody response to the ChAdOx1 nCoV-19 vaccine (AZD1222; Covishield®) in cirrhosis. We studied the antibody response following two doses of the ChAdOx1 vaccine, given 4-12 weeks apart, in cirrhosis. METHODS: Prospectively enrolled, 131 participants (71% males; age 50 (43-58); alcohol-related etiology 14, hepatitis B 33, hepatitis C 46, cryptogenic 21, autoimmune 9, others 8; Child-Turcott-Pugh class A/B/C 52/63/16). According to dose intervals, the participants were grouped as ≤6 weeks (group I), 7-12 weeks (group II), and 13-36 weeks (group III). Blood specimens collected at ≥4 weeks after the second dose were tested for anti-spike antibody titre (ASAb; positive ≥ 0.80 U/mL) and neutralizing antibody (NAb; positive ≥20% neutralization) using Elecsys Anti-SARS-CoV-2 S (Roche) and SARS-CoV-2 NAb ELISA Kit (Invitrogen), respectively. Data are expressed as number (proportion) and median (interquartile range) and compared using non-parametric tests. RESULTS: Overall, 99.2% and 84% patients developed ASAb (titre 5440 (1719-9980 U/mL)) and NAb (92 (49.1-97.6%)), respectively. When comparing between the study groups, the ASAb titres were significantly higher in group II than in group I (2613 (310-7518) versus 6365 (2968-9463), p = 0.027) but were comparable between group II and III (6365 (2968-9463) versus 5267 (1739-11,653), p = 0.999). Similarly, NAb was higher in group II than in group I (95.5 (57.6-98.0) versus 45.9 (15.4-92.0); p < 0.001), but not between the groups II and III (95.5 (57.6-98.0) versus 92.4 (73.8-97.5); p = 0.386). CONCLUSION: Covishield® induces high titres of ASAb and NAb in cirrhosis. A higher titre is achieved if two doses are given at an interval of more than six weeks.
ABSTRACT
Kidney transplant recipients (KTRs) are at a much higher risk of complications and death following COVID-19 and are poor vaccine responders. The data are limited on the immune response to Covishield® in KTRs. We prospectively recruited a cohort of 67 KTRs aged >18 between April 2021 and December 2021. Each participant was given two intramuscular doses of Covishield®, each of 0.5 mL, at an interval of 12 weeks. A blood specimen of 5.0 mL was collected from each participant at two points within a few days before administering the first dose of the vaccine and at any time between 4-12 weeks after administering the second dose. The sera were tested for anti-RBD antibody (ARAb) titre and neutralising antibody (NAb). An ACE2 competition assay was used as a proxy for virus neutralization. According to the prior COVID-19 infection, participants were grouped as (i) group A: prior symptomatic COVID-19 infection, (ii) group B: prior asymptomatic COVID-19 infection as evidenced by detectable ARAb in the prevaccination specimen, (iii) Group C: no prior infection with COVID-19, (iv) group D: Unclassified, i.e., participants had no symptoms suggestive of COVID-19, but their prevaccination specimen was not available for ARAb testing before vaccination. Fifty of sixty-seven participants (74.6%) provided paired specimens (group A 14, group B 27, and group C 9) and 17 participants (25.4%) provided only postvaccination specimens (group D). In the overall cohort (n = 67), 91% and 77.6% of participants developed ARAb and NAb, respectively. Their ARAb titre and NAb proportion were 2927 (520-7124) U/mL and 87.9 (24.4-93.2) %, respectively. Their median ARAb titre increased 65.6 folds, from 38.2 U/mL to 3137 U/mL. Similarly, the proportion of participants with NAb increased from 56% to 86%, and the NAb proportion raised 2.7 folds, from 23% to 91%. A comparison of vaccine response between the study groups showed that all those with or without prior COVID-19 infection showed a significant rise in ARAb titre (p < 0.05) and NAb proportion (p < 0.05) after the two doses of vaccine administration. The median value of folds rise in anti-RBD and NAb between groups A and B were comparable. Hence, ARAb is present in more than 3/4th of KTRs before the ChAdOx1 vaccine in India. The titer of ARAb and the proportion of NAb significantly increased after the two doses of the ChAdOx1 vaccine in KTRs.