D. Collier, B. Meng, I. Ferreira, R. Datir, N. Temperton, A. Elmer, B. Graves, N. Kingston, L. McCoy, K. Smith, J. Bradley, R. Doffinger, R. Gupta
medRxiv, 2021
SARS-CoV-2 transmission is uncontrolled in many parts of the world, compounded in some areas by higher transmission potential of the B1.1.7 variant now seen in 50 countries. In addition, many countries are extending the interval between doses of vaccine is being extended in order to expand vaccine coverage. It is unclear whether real world neutralising antibody titres will follow those in clinical trials, particularly in elderly persons, and how this will be impacted by mutations in strains such as B1.1.7. Here we tested immune responses in patients 3 weeks following the first dose of the Pfizer BioNTech vaccine BNT162b2. We also tested neutralising antibody responses against pseudoviruses expressing wild type Spike proteins or expressing 3 key mutations present in B.1.1.7 (deletion 69/70, N501Y, A570D). IgG Spike antibody titres correlated well with neutralisation. We observed a range of neutralisation titres against wild type, with geometric mean titre (GMT) of 24. The vaccine sera exhibited a range of inhibitory dilutions giving 50% neutralisation (ID50) from <1:4 to 3449. However a lower proportion of participants over 80 years old achieved threshold neutralisation titre of >1:4 for 50% neutralisation as compared to those under 80 years old (8/15 versus 8/8 P=0.052) after the first dose. Neutralisation titres were not significantly impacted by the combination of three Spike mutations tested, but were reduced against the full set of Spike mutations present in the B.1.1.7 variant. The highest fold change was approxiamately 6 and the median fold change for the B.1.1.7 variant versus wild type was 3.85 (IQR 2.68-5.28). Further work is needed to establish the impact of these observations on real life vaccine efficacy.
Cited by 17 publications.
Field of study: Medicine