Exponential increase in neutralizing and spike specific antibodies following vaccination of COVID‐19 convalescent plasma donors

Abstract

Background: With the recent approval of COVID-19 vaccines, recovered COVID-19 subjects who are vaccinated may be ideal candidates to donate COVID-19 convalescent plasma (CCP).Case Series: Eleven recovered COVID-19 patients were screened to donate CCP. All had molecularly confirmed COVID-19, and all but one were antibody positive by chemiluminescence immunoassay (DiaSorin) prior to vaccination.All were tested again for antibodies 11-21 days after they were vaccinated (Pfizer/Moderna). All showed dramatic increases (50-fold) in spike-specific antibody levels and had at least a 20-fold increase in the IC50 neutralizing antibody titer based on plaque reduction neutralization testing (PRNT). The spike-specific antibody levels following vaccination were significantly higher than those seen in any non-vaccinated COVID-19 subjects tested to date at our facility. Conclusion:Spike-specific and neutralizing antibodies demonstrated dramatic increases following a single vaccination after COVID-19 infection, which significantly exceeded values seen with COVID-19 infection alone. Recovered COVID-19 subjects who are vaccinated may make ideal candidates for CCP donation. K E Y W O R D Simmunology (other than RBC serology), transfusion Practices (Adult) | INTRODUCTIONThe emergence of SARS-CoV-2, the cause of COVID-19, has resulted in intense efforts to identify new and effective treatments. The lack of proven effective antiviral therapies against coronaviruses has led to the broad utilization of COVID-19 convalescent plasma (CCP) obtained from survivors of COVID-19 to treat patients with active disease. [1][2][3] While the mechanism of action of CCP is uncertain, the most prevalent hypothesis is that CCP contains neutralizing antibodies that limit viral spread and † Contributed equally; co-first authors.

Understanding neutralising antibodies against SARS-CoV-2 and their implications in clinical practice

“…However, neutralising antibody activity against certain viral variants-of-concern was reduced by a small but significant margin [ 94 ]. Vickers et al [ 48 ] reported that non-vaccinated subjects had an average spike-specific antibody level of 81.7 AU/ml, whereas their vaccinated counterparts all had antibody levels greater than 1200 AU/ml and at least tenfold higher than before vaccination.…”

Waning antibody responses in COVID-19: what can we learn from the analysis of other coronaviruses?

“…Single-dose vaccination of patients with previous SARS-CoV-2 exposure has been found to induce dramatic increases in titres of anti-spike IgG and nAbs [ 127 ], rivalling titres generated after booster doses in infection-naïve subjects [ 128 , 129 ]. Antibody responses after a single vaccine dose in those previously infected develop quicker and reach higher titres [ 123 ], a phenomenon occurring even when anti-spike IgG from previous SARS-CoV-2 infection had waned to low or undetectable levels [ 124 ], indicating immune memory despite waning of antibodies.…”

Early post-infection treatment of SARS-CoV-2 infected macaques with human convalescent plasma with high neutralizing activity reduces lung inflammation

“…First of all, as very few people who recover from COVID-19 develop persistently high neutralizing antibody titers, the use of CCP from such donors faces increasing logistical and scientific hurdles, especially considering the increased availability of potent monoclonal antibodies. However, recent studies have demonstrated that COVID-19 survivors who subsequently received a SARS-CoV-2 vaccine made very strong booster immune responses, which also neutralize currently circulating variants of concern [38][39][40][41][42][43][44]. Thus, vaccinated COVID-19 recovered subjects are likely to be a much better source of CCP.…”