Vaccine Subtype and Dose Interval Determine Immunogenicity of Primary Series COVID-19 Vaccines in Older People
29 Pages Posted: 27 Apr 2022 Publication Status: PublishedMore...
SARS-CoV-2 vaccines mediate strong clinical protection against COVID-19 and over 2 billion people have received primary series vaccination with BNT162b2 (mRNA) or ChAdOx1 (adenoviral vector). Age is the strongest determinant of COVID-19 mortality but the profile of sustained vaccine immunogenicity in older people is unknown. We determined spike-specific humoral and cellular immunity to 8 months following BNT162b2 or ChAdOx1 in 245 people age 80-98 years. Both vaccines were strongly immunogenic with antibodies retained in every donor whilst titers fell to 23-26% of peak value. Antibody titer was enhanced 3.7-fold with extended interval BNT162b2 dosage and neutralisation was superior following BNT162b2. Conversely, cellular immune responses were stronger following ChAdOx1 and retained to 33-60% of peak value with all vaccines. BNT162b2 and ChAdOx1 elicit strong but differential sustained immunogenicity in older people. These data provide a baseline to assess ongoing immune memory and optimal booster vaccine regimen in this vulnerable age group.
Funding Information: This work was supported by the National Core Studies Immunity programme and the UK Coronavirus Immunology Consortium (UK-CIC) funded by NIHR/UKRI. Funding to BW was provided by BBSRC BB/R004250/1 and BB/R019843/1.
Conflict of Interests: The authors declare no conflicts of interest.
Ethical Approval: Ethical approval was obtained from North West Preston Research Ethics Committee with favourable outcome (REC 20\NW\0240) and work was performed under the CIA UPH and conducted according to the Declaration of Helsinki and good clinical practice.
Keywords: COVID-19, vaccines, elderly, primary series, BNT162b2, ChAdOx1
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