Immune responses to a single dose of the AZD1222/Covishield vaccine at 16 weeks in individuals in Sri Lanka

<p>Due to limited access to vaccines, many countries have only administered a single dose of the AZD1222, whereas the dosage intervals have increased &ge;4 wk. We sought to investigate the immunogenicity of a single dose of vaccine at &ge;16 wk postimmunization. Severe acute respirator...

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Xehetasun bibliografikoak
Egile Nagusiak: Jeewandara, C, Guruge, D, Pushpakumara, PD, Kamaladasa, A, Aberathna, IS, Ramu, ST, Gunasekera, B, Wijesinghe, A, Dissanayake, O, Kuruppu, H, Ranasinghe, T, Jayathilaka, D, Dayarathna, S, Ekanayake, D, Jayamali, J, Gamalath, N, Mudunkotiwa, A, Somathilake, G, Dissanayake, M, Harvie, M, Nimasha, T, Madusanka, D, Jayadas, T, Wijayamuni, R, Schimanski, L, Rijal, P, Tan, TK, Townsend, A, Ogg, GS, Malavige, GN
Formatua: Journal article
Hizkuntza:English
Argitaratua: American Association of Immunologists 2021
Deskribapena
Gaia:<p>Due to limited access to vaccines, many countries have only administered a single dose of the AZD1222, whereas the dosage intervals have increased &ge;4 wk. We sought to investigate the immunogenicity of a single dose of vaccine at &ge;16 wk postimmunization. Severe acute respiratory syndrome coronavirus 2&ndash;specific Abs in 553 individuals and Abs to the receptor-binding domain of the Wuhan virus (wild-type) and the variants of concern, angiotensin-converting enzyme 2 receptor blocking Abs ex vivo and cultured IFN-&gamma; T cell (<em>Homo sapiens</em>) responses and B cell (<em>H. sapiens</em>) ELISPOT responses, were investigated in a subcohort. The seropositivity rates in those &gt;70 y of age (93.7%) was not significantly different compared with other age groups (97.7&ndash;98.2; Pearson &chi;<sup>2</sup>&nbsp;= 7.8;&nbsp;<em>p</em>&nbsp;= 0.05). The Ab titers (Ab index) significantly declined (<em>p</em>&nbsp;&lt; 0.0001) with increase in age. A total of 18 of 69 (26.1%) of individuals did not have angiotensin-converting enzyme 2 receptor&ndash;blocking Abs, whereas responses to the receptor-binding domain of wild-type (<em>p</em>&nbsp;= 0.03), B.1.1.7 (<em>p</em>&nbsp;= 0.04), and B.1.617.2 (<em>p</em>&nbsp;= 0.02) were significantly lower in those who were &gt;60 y. Ex vivo IFN-&gamma; T cell ELISPOT responses were seen in 10 of 66 (15.1%), whereas only a few expressed CD107a. However, &gt;85% had a high frequency of cultured IFN-&gamma; T cell ELISPOT responses and B cell ELISPOTs. Virus-specific Abs were maintained at &ge;16 wk after receiving a single dose of AZD1222, although levels were lower to variants of concern, especially in older individuals. A single dose induced a high frequency of memory T and B cell responses.</p>