SUMMARY/ABSTRACT
Although more than four years have passed since the initial virus appearance, nowadays, most of the population has been
vaccinated with multiple doses of mRNA-based vaccines and has endured multiple infection events. Still, SARS-CoV-2
continues to cause disproportionately higher morbidity and mortality in older adults from these communities, especially in
the Latino-origin population and other vulnerable populations like the hematopoietic stem cell transplants (HSCT)
population. As newer versions of vaccines are adapted to recent SARS-CoV-2 variants (i.e., bivalent vaccines andXBB1.5),
we must continue to determine how effective these vaccines are overtime against emerging variants and establish how those
populations are still responding. We will characterizes the kinetics, magnitude, and durability of type-specific neutralizing
antibody and T cells responses to different current SARS-CoV-2 variants after natural infection or vaccination, designed to
reveal correlates associated with protective immunity or disease severity or progression to long COVID. We pursue to
implement the following new tasks: AIM 1: Task 1.3. Implementation of a third Community Assessment for Public Health
Emergency Response (CASPER) approach, we expect to collect about 2,000 new samples to expand the IDRB. During
prior funding periods, we also supported CASPER I and II. AIM 2: Task 2.5: To evaluate the current anti-SARS-Cov-2 IgG
levels in the population of Puerto Rico following the Community Assessment for Public Health Emergency Response
(CASPER) approach. Task 2.6: characterizes the kinetics, magnitude, and durability of type-specific neutralizing antibody
responses to different current SARS-CoV-2 variants designed to reveal correlates associated with protective immunity. Task
2.7: Supported in our prior findings, we propose determining whether such IgG4 levels induced by mRNA vaccination
could be associated with persistent COVID-19 symptoms (Long-COVID) in our population. Task 2.8: Interrogation of the
Antigen-Specific B Cell Response as described below in the approach section. Task 2.9: Breakthrough SARS-CoV-2
Infections: Investigate the relationship between breakthrough infections, vaccine immunogenicity, and long COVID
symptomatology by actively monitoring HSCT patients. AIM3: Task 3.2: Expand the Innate and Adaptive Immune
Response characterization in underrepresented populations: Investigate the phenotype and function of antigen-specific T
cells, including TFH cells, which support antigen-specific B cell responses. Measure CD4 TFH cells' ability to support
antigen-specific B cell antibody secretion using in vitro CD4-B cell cultures. Task 3.3: Define factors responsible for
decreased T cell help leading to altered antigen-specific antibody responses in patients with HSCTs. AIM 4: Task 4.3: We
will continue to focus on sequencing the circulating and emerging strains and variants and correlating them with the
immunological profile characterized under the new tasks in aims 1 to 3.
We will continue with our efforts directed to guarantee a proper representation of age, sex, gender, and socioeconomic
status as well as individuals with comorbidities including but not limited to obesity, cancer, and autoimmune diseases.