Qualitative Assessment of Anti-SARS-CoV-2 Spike Protein Immunogenicity (QUASI) After COVID-19 Vaccination in Older People Living With HIV

Jessica J. Tuan; Heidi Zapata; Terese Critch-Gilfillan; Linda Ryall; Barbara Turcotte; Suzana Mutic; Laurie Andrews; Michelle E. Roh; Gerald Friedland; Lydia Barakat; Onyema Ogbuagu


HIV Medicine. 2022;23(2):178-185. 

In This Article


Study Design, Participants and Data Sources

Following expanded eligibility for COVID-19 vaccination in Connecticut to individuals aged 55 years and older, and prioritizing individuals with significant medical comorbidities, we conducted targeted COVID-19 vaccination of PLWH who were receiving care at any of two HIV clinics of the Yale New Haven Health System (YNHHS). Coincident with planning the vaccination event, we established a longitudinal survey to assess qualitative SARS-CoV-2 immune responses using point-of-care tests under the US Food and Drug Administration (FDA) Emergency Use Authorization (EUA) over a 6-month period post-vaccination among the PLWH receiving any type of COVID-19 vaccine under the US FDA EUA. At the time of study enrolment, only the BNT162b2 vaccine was being offered to these individuals. Inclusion criteria were having laboratory-confirmed HIV diagnoses, receiving care at YNHHS (allowing access to their medical histories and laboratory tests), ability to provide informed consent and willingness to participate in the study for the intended duration of follow-up. We excluded patients who participated in COVID-19 vaccine trials, those who had prior laboratory-confirmed COVID-19 diagnosis, and those with invalid SARS-CoV-2 antibody test results.

Individuals identified as PLWH were recruited from a prepopulated hospital vaccination schedule, ahead of their scheduled date, through phone calls by study investigators and were scheduled for research study visits. Three visits were planned: visit 1 was conducted 3 weeks after the first dose of their vaccine and coincident with patients presenting for their second vaccination (before receiving the vaccine); visit 2 was conducted 2 weeks (+1 week window) after receipt of the second vaccination; visit 3 was planned for 6 months (±2 week window) after the initial vaccination. A research site was established at the vaccination centre for visit 1 for patient convenience, while visits 2 and 3 were conducted at the YNHHS HIV clinic. Only subjects who participated in visit 1 were again contacted via telephone call by research staff to participate in visit 2. In this ongoing study, all patients who participated in visits 1 and/or 2 and had a positive SARS-CoV-2 IgG test will be approached for participation in visit 3 in the future. We would exclude patients who received a third or booster dose of vaccine or who are confirmed to have acquired COVID-19 in between visits 2 and 3.

SARS-CoV-2 Vaccine Immunogenicity Testing

We performed qualitative SARS-CoV-2 vaccine immunogenicity testing utilizing a point-of-care test, Healgen (Houston, TX, USA) COVID-19 anti-Spike IgG/IgM Rapid Test Cassette, a platform that is under EUA by the US FDA [96.7% sensitivity (IgG), 97.5% specificity (IgM/IgG)] utilizing whole blood specimens and conducted per test specifications. This Healgen lateral flow assay point-of-care test produces a binary result (positive or negative) for SARS-COV-2 anti-spike antibody for both IgG and IgM. Its ability to serve as an accurate point-of-care serology test for COVID-19 has been substantiated.[10] It has been tested predominantly among healthcare workers in a real-world clinical setting, and when compared with a CLIA laboratory-based serum immunoassay antibody test, it demonstrated 93.2% sensitivity and 94.9% specificity in one study.[10] The qualitative antibody lateral flow immunoassay test was selected due to ease of performance in our study, which was being carried out in the context of vaccination implementation in a care and community-based and/or clinic setting (and not a specific research site), amidst the ongoing pandemic. Qualitative lateral flow antibody immunoassays have been compared with a quantitative SARS-CoV-2 antibody assay (Euroimmun, Lübeck, Germany) with percentages of 81–91.5% overall.[11]

The research staff performed venepuncture to obtain about 1 mL of peripheral venous blood sample per participant (this was increased to 3 mL of blood for visit 2 as we later amended the study to allow us to accrue a specimen repository for future research). For the point-of-care test, a dropper was utilized to add one drop of whole blood to the appropriate well in the test cassette, which is a lateral flow assay, and subsequently one to two drops of buffer provided in the test package were added to the separate designated well as per the package insert instructions. Although the test reports SARS-CoV-2 anti-Spike IgG and IgM results as early as 2 min, the results were uniformly interpreted at 15 min as per the package insert guidelines by research staff, who interpreted and documented these SARS-CoV-2 immunogenicity results onto paper files. Where test results were difficult to interpret by a single member of the research staff, one to two additional research staff adjudicated the result.

Data Collection

Medical record review (Epic electronic medical record; Epic Systems Corporation, Verona, Wisconsin, USA) was conducted to obtain patient demographics (age, sex, race/ethnicity), body mass index, medical history including prior COVID-19 diagnosis, medical comorbidities [cancer (i.e. active cancer or actively receiving chemotherapy) or other immunosuppressive condition (i.e. transplant recipient, chronic use of immunosuppressant medication), diabetes mellitus, cardiovascular disease (i.e. coronary artery disease, myocardial infarction, stroke and peripheral vascular disease), lung disease (i.e. chronic obstructive pulmonary disease, asthma, interstitial lung disease), advanced liver disease, chronic kidney disease of any stage], self-reported substance use, years since HIV diagnosis, HIV antiretroviral therapy (ART) regimen and other laboratory data, such as most recent CD4 count and HIV viral load. Results of immunogenicity testing (Table 1) were entered into each patients' unique study folders and all data obtained were subsequently transferred to a deidentified Microsoft Excel (v.16.39) database.

Statistical Analysis

Descriptive statistics were utilized to report patient demographics and clinical characteristics stratified by presence or absence of anti-Spike IgG response. Bivariate and multivariate analyses estimating the association between predictor variables and having a positive IgG response after the first dose were performed using Poisson regression with robust standard errors, given Poisson regression is usually used to estimate incidence rate ratios and the modified version (with robust standard errors) allows us to estimate relative risk ratios.[12] The final multivariate model included predictors with a p-value < 0.2 in the bivariate analyses. All analyses used two-sided tests with α = 0.05. Analyses were performed using Stata v.16.1 (StataCorp, College Station, TX, USA). Given that all but one subject did not seroconvert after the two doses, predictors of seroconversion after the second dose were not assessed.

Ethical Approval

This study received Human Investigations Committee approval from Yale. Participation was allowed only after informed consent was provided without coercion of any form. Small stipends were provided to each participant during each visit.