Study cohort
This study received ethical approval from the Wales Research Ethics
Committee 5 (IRAS number: 286991). To investigate T cell responses in
naturally infected individuals, participants from across Wales and
England were recruited to the project between June-December 2020. All
participants gave written, informed consent prior to inclusion. At the
time of blood sample collection, corresponding details of prior test
results for SARS-CoV-2 infection, confirmed by using PCR with reverse
transcription from a nose and throat swab performed by public health
bodies at accredited laboratories were obtained via questionnaire. Those
that had a positive PCR test were assigned to the ‘Confirmed infection
(PCR positive’) cohort (n=29). Participants were also asked if they had
ever tested positive for SARS-CoV-2 via a lateral flow test, and to note
any COVID-19-related symptoms they had experienced as well as record any
close contact they had with persons who had been confirmed positive by
PCR. Those that had a positive lateral flow test, experienced
COVID-19-like symptoms or had close contact with a positive individual
were assigned to the ‘Suspected infection/exposure’ cohort (n=30). All
other individuals were assigned to the ‘No history of exposure’ cohort
(n=69). None of the participants were hospitalised due to COVID-19 at
any time before or during the study.
To investigate T cell responses in vaccinated individuals, participants
from across Wales, England and the US were recruited to the project
between December 2020 and March 2021. All participants gave written,
informed consent prior to inclusion. At the time of blood sample
collection, details of prior test results for SARS-CoV-2 infection and
details of SARS-CoV-2 vaccinations including date and vaccine
manufacture were obtained via questionnaire: 26 donors received the
Pfizer-BioNTech vaccine, 5 received the Oxford-AstraZeneca vaccine and 1
received the Johnson and Johnson/Janssen vaccine.