ABSTRACT
BACKGROUND: Within a year of the SARS-CoV-2 pandemic, vaccines inducing a robust humoral and cellular immune response were implemented worldwide. However, emergence of novel variants and waning vaccine induced immunity led to implementation of additional vaccine boosters. METHODS: This prospective study evaluated the temporal profile of cellular and serological responses in a cohort of 639 SARS-CoV-2 vaccinated participants, of whom a large proportion experienced a SARS-CoV-2 infection. All participants were infection naïve at the time of their first vaccine dose. Proportions of SARS-CoV-2 Spike-specific T cells were determined after each vaccine dose using the Activation Induced Markers (AIM) assay, while levels of circulating SARS-CoV-2 antibodies were determined by the Meso Scale serology assay. RESULTS: We found a significant increase in SARS-CoV-2 Spike-specific CD4+ and CD8+ T cell responses following the third dose of a SARS-CoV-2 mRNA vaccine as well as enhanced CD8+ T cell responses after the fourth dose. Further, increased age was associated with a poorer response. Finally, we observed that SARS-CoV-2 infection boosts both the cellular and humoral immune response, relative to vaccine-induced immunity alone. CONCLUSION: Our findings highlight the boosting effect on T cell immunity of repeated vaccine administration. The combination of multiple vaccine doses and SARS-CoV-2 infections maintains population T cell immunity although with reduced levels in the elderly.
ABSTRACT
INTRODUCTION AND OBJECTIVES: The HepHIV 2023 Conference, held in Madrid in November 2023, highlighted how Europe is not on track to meet the United Nations (UN) sustainable development goals and Joint UN Programme on HIV/AIDS (UNAIDS) targets. This article presents the outcomes of the conference, which focus on ways to improve testing and linkage to care for HIV, viral hepatitis, and other sexually transmitted infections. HIV-related stigma and discrimination, a major barrier to progress, was a key concept of the conference and on the agenda of the Spanish Presidency of the European Union. METHODS: The HepHIV 2023 organizing committee, alongside the Spanish Ministry of Health, oversaw the conference organization and prepared the scientific programme based on abstract rankings. Key outcomes are derived from conference presentations and discussions. RESULTS: Conference presentations covered the obstacles that HIV-related stigma and discrimination continue to pose to access to services, models for data collection to better monitor progress in the future, and examples of legislative action that can be taken at national levels. Diversification of testing approaches was also highlighted, to reach key populations, (e.g. migrant populations), to increase testing offered in healthcare settings (e.g. emergency departments), and to account for different stages of epidemics across the region. CONCLUSION: With a strong call for intensified action to address the impact of HIV-related stigma and discrimination on testing uptake, the conference concluded that strengthened collaboration is required between governments and implementers around testing and linkage to care. There is also an ongoing need to ensure sustainable political commitment and appropriate resource allocation to address gaps and inequalities in access for key populations and to focus on the implementation of integrated responses to HIV, viral hepatitis, and sexually transmitted infections.