Compared to the DK-AHH1 isolate, neutralisation of the delta and omicron isolates remained significantly lower (p<0.0001, 2way ANOVA, 2-fold and 13.6-fold reduction, respectively) after vaccination. == Fig.7. contamination, as well as booster vaccination, increases the cross-neutralising potential to both delta and omicron SARS-CoV-2 variants. == Interpretation == Taken together, these results suggest that neither type of antigen exposure is usually superior for neutralising antibody durability. However, these results support vaccination to increase the durability and cross-neutralisation potential of neutralising responses, thereby enhancing protection against severe COVID-19. == Funding == This work was supported by grants from The Capital Region of Denmarks Research Foundation, the Novo Nordisk Foundation, the Independent Research Fund Denmark, the Candys Foundation, and the Danish Agency for Science and Higher Education. Keywords:Neutralising antibody, SARS-CoV-2, COVID-19, Longitudinal, Cross-neutralisation, Delta, Omicron, Computer virus isolate == Research in context. == == Evidence before this study == Publications in relation to this study were searched in MEDLINE, PubMed and Embase using the search terms severe acute respiratory syndrome coronavirus 2, SARS-CoV-2, COVID-19, Longitudinal, breadth/broad, neutralization/neutralisation, antibody, dynamics and kinetics, which 2-Keto Crizotinib have been published up until 31 August 2022. Articles published in medRxiv and BioRxiv were not considered. A total of six major studies were found, which assessed longitudinal neutralising antibody responses as well as breadth of these responses after SARS-CoV-2 contamination, COVID-19 vaccination, and/or a mix thereof. Common limitations amongst these studies included limited comparisons between the infected/vaccinated groups, limited follow up (up to one year), use of neutralisation to pseudo-typed models and lack of detection of possible reinfection. == Added value of this study == This study provides a thorough longitudinal analysis, with detection of possible contamination and reinfection, as well as time-matched comparisons of neutralising antibody levels between infected, vaccinated, infected-vaccinated, vaccinated-boosted, and vaccinated-infected individuals with up to two years follow-up. The neutralising assays used in this study were of SARS-CoV-2 isolates, which clustered well with the sequences retrieved from infected individuals, and not pseudo-typed models. Breadth of neutralisation was also assessed using a select panel of each study group to understand the differences between each type of antigen exposure. == Implications of all the available evidence == Regardless of antigen exposure type, whether that be through vaccination or contamination, the durability of neutralising titres in plasma are comparable, suggesting that neither type is usually superior. Additional antigen exposure, either through vaccination or contamination, appears to improve the durability and breadth of neutralising responses when compared to that before vaccination or contamination. If a boosting antigen is similar to that seen during a previous exposure, the breadth of neutralising responses is usually significantly increased to all other known variants, including the more recently discovered omicron variant. == Introduction == Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic ultimo 2019, coronavirus disease 2019 (COVID-19) has claimed the lives of hundreds of thousands worldwide.1During late 2020, several COVID-19 vaccines were developed and given emergency use authorization worldwide. Initially, they showed high protection efficacy against development of severe COVID-19,2,3,4but since then, the protection efficacy of these vaccines has decreased.5,6,7This is most likely due to a combination of waning immunity and emerging SARS-CoV-2 variants of concern (VOCs), which, compared to ancestral variants, differ in their transmissibility levels and are more resistant to vaccine-induced immunity and immunity induced by previous infection.8,9,10,11To improve protective efficacies, booster vaccination programs have now been implemented as a standard of practice for many countries worldwide. One of the main goals for vaccination against COVID-19 is the induction of neutralising antibodies (nAbs) that target the surface located spike (S) protein of the computer virus. Recent analyses have shown that nAbs are a strong correlate of protection from severe COVID-19,12,13making them an ideal target for measuring protection efficacy. In the case of SARS-CoV-2, it is believed that most nAbs target epitopes are located within the S protein14,15. Analysis Enpep of emerging delta and omicron VOCs has shown that they carry specific amino acid changes in this protein, which likely account for the observed diminished neutralisation efficacy from prior contamination or vaccination.16,17 In addition to anti-S antibodies, antibodies directed to the nucleocapsid (N) protein of the computer virus are also detected during SARS-CoV-2 infection.18Although these antibodies have correlated with neutralising activity,19their functionality remains putative. 2-Keto Crizotinib An advantage of eliciting antibodies to N is usually that they allow for discrimination of prior contamination in those that have been vaccinated with Comirnaty, Spikevax, Vaxzevria and Jcovden, as these vaccines only target the S protein. While there 2-Keto Crizotinib have been several studies on.