Quantifying neutralising antibody responses against SARS-CoV-2 in dried blood spots (DBS) and paired sera
Authors: Roper Kelly J. , Thomas Jordan , Albalawi Wejdan , Maddocks Emily , Dobson Susan , Alshehri Abdullateef , Barone Francesco G. , Baltazar Murielle , Semple Malcolm G. , Ho Antonia , Turtle Lance ,   ISARIC4C Consortium, Donegan Cara , Spencer Rebecca G. , Moore Shona C. , Hardwick Hayley , Solomon Tom , Turtle Lance C. W. , da Silva Filipe Ana , Ho Antonia Ying Wai , McDonald Sarah E. , Palmarini Massimo , Robertson David L. , Scott Janet T. , Thomson Emma C. , Chand Meera , Tedder Richard S. , Price Nicholas , Leeming Gary , Bogaert Debby , Russell Clark D. , Docherty Annemarie B. , Drake Thomas M. , Fairfield Cameron J. , Harrison Ewen M. , Knight Stephen R. , Mclean Kenneth A. , Murphy Derek , Norman Lisa , Pius Riinu , Shaw Catherine A. , Horby Peter W. , Swann Olivia V. , Chechi Kanta , Thompson A. A. Roger , Cooke Graham S. , Sriskandan Shiranee , Summers Charlotte , Greenhalf William , Sancho-Shimizu Vanessa , Khoo Saye , Noursadeghi Mahdad , Stuart David , Norris Lucy , Gupta Rishi K. , Rambaut Andrew , Green Christoper A. , Shaw Victoria , Keating Seán , Carson Gail , Merson Laura , Sigfrid Louise , Lee James , Plotkin Daniel , Connor Marie , Dalton Jo , Donohue Chloe , Gamble Carrol , Girvan Michelle , Halpin Sophie , Harrison Janet , Jackson Clare , Marsh Laura , Roberts Stephanie , Saviciute Egle , Fletcher Tom , Palmieri Carlo , Meynert Alison M. , Wham Murray , Openshaw Peter J. M. , Thwaites Ryan S. , Dunning Jake , Zambon Maria , dos Santos Correia Gonçalo , Lewis Matthew R. , Maslen Lynn , Sands Caroline J. , Takis Panteleimon , Lim Wei Shen , Mentzer Alexander J. , Klenerman Paul , Grammatikopoulos Tassos , Knight Susan , Tait Sarah , Baillie J. Kenneth , Clohisey Sara , Griffiths Fiona , Hendry Ross , Law Andrew , Oosthuyzen Wilna , Alex Beatrice , Bach Benjamin , Scott-Brown James , Andrikopoulos Petros , Dumas Marc-Emmanuel , Griffin Julian L. , Liggi Sonia , Olanipekun Michael , Osagie Anthonia , Takats Zoltan , Barclay Wendy S. , de Silva Thushan , Ijaz Samreen , Paxton William A. , Pollakis Georgios 
Published: September 2023

The ongoing SARS-CoV-2 pandemic was initially managed by non-pharmaceutical interventions such as diagnostic testing, isolation of positive cases, physical distancing and lockdowns. The advent of vaccines has provided crucial protection against SARS-CoV-2. Neutralising antibody (nAb) responses are a key correlate of protection, and therefore measuring nAb responses is essential for monitoring vaccine efficacy. Fingerstick dried blood spots (DBS) are ideal for use in large-scale sero-surveillance because they are inexpensive, offer the option of self-collection and can be transported and stored at ambient temperatures. Such advantages also make DBS appealing to use in resource-limited settings and in potential future pandemics. In this study, nAb responses in sera, venous blood and fingerstick blood stored on filter paper were measured. Samples were collected from SARS-CoV-2 acutely infected individuals, SARS-CoV-2 convalescent individuals and SARS-CoV-2 vaccinated individuals. Good agreement was observed between the nAb responses measured in eluted DBS and paired sera. Stability of nAb responses was also observed in sera stored on filter paper at room temperature for 28 days. Overall, this study provides support for the use of filter paper as a viable sample collection method to study nAb responses.