Open AccessKinetics of immune responses to the AZD1222/Covishield vaccine with varying dose intervals in Sri Lankan individuals
Author(s) -
Jeewandara Chandima,
Aberathna Inoka Sepali,
Gomes Laksiri,
Pushpakumara Pradeep Darshana,
Danasekara Saubhagya,
Guruge Dinuka,
Ranasinghe Thushali,
Gunasekera Banuri,
Kamaladasa Achala,
Kuruppu Heshan,
Somathilake Gayasha,
Dissanayake Osanda,
Gamalath Nayanathara,
Ekanayake Dinithi,
Jayamali Jeewantha,
Jayathilaka Deshni,
Mudunkotuwa Anushika,
Harvie Michael,
Nimasha Thashmi,
Wijayamuni Ruwan,
Schimanski Lisa,
Rijal Pramila,
Tan Tiong K.,
Dong Tao,
Townsend Alain,
Ogg Graham S.,
Malavige Gathsaurie Neelika
Publication year - 2022
Publication title -
immunity, inflammation and disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 18
ISSN - 2050-4527
DOI - 10.1002/iid3.592
Subject(s) - cohort , medicine , dosing , antibody , ex vivo , titer , immunology , antibody titer , elispot , immune system , in vivo , t cell , biology , microbiology and biotechnology
Background To understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps. Methods Antibodies to the SARS‐CoV‐2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2‐blocking antibodies (ACE2‐blocking Abs), antibodies to the receptor‐binding domain (RBD) of variants of concern (VOC), and ex vivo T cell responses were assessed in a subcohort. Results All individuals (100%) had SARS‐CoV‐2‐specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2‐blocking Abs. There was no difference in antibody titers or positivity rates in different age groups in both cohorts. The ACE2‐blocking Abs ( p < .0001) and antibodies to the RBD of the VOCs were significantly higher in cohort 2 compared to cohort 1. 41.2% to 65.8% of different age groups gave a positive response by the hemagglutination assay to the RBD of the ancestral virus and VOCs in cohort 1, while 53.6%–90% gave a positive response in cohort 2. 17/57 (29.8%) of cohort 1 and 17/29 (58.6%) of cohort 2 had ex vivo interferon (IFN)γ ELISpot responses above the positive threshold. The ACE2‐blocking antibodies (Spearman's r = .46, p = .008) and ex vivo IFNγ responses (Spearman's r = .71, p < .0001) at 12 weeks post first dose, significantly correlated with levels 12 weeks post second dose. Conclusions Both dosing schedules resulted in high antibody and T cell responses post vaccination, although those with a longer dosing gap had a higher magnitude of responses, possibly as immune responses were measured 6 weeks post second dose compared to 12 weeks post second dose.