Faculty Bibliography

Background/Purpose Remission and low disease activity (LDA) are associated with decreased flares, damage, and mortality. However, little is known about the impact of disease activity states (DAS) on health care costs. We determined the independent impact of different definitions of remission and LDA on direct and indirect costs (DC, IC) in a multicentre, multiethnic inception cohort. Methods Patients fulfilling revised ACR classification criteria for SLE from 33 centres in 11 countries were enrolled within 15 months of diagnosis and assessed annually. Patients with >=2 annual assessments were included. Five mutually independent DAS were defined: 1) Remission off-treatment: clinical (c) SLEDAI-2K=0, without prednisone or immunosuppressants 2) Remission on-treatment: cSLEDAI-2K=0, prednisone <=5mg/d and/or maintenance immunosuppressants 3) LDA-Toronto Cohort (TC): cSLEDAI-2K<=2, without prednisone or immunosuppressants 4) Modified Lupus LDA State (mLLDAS): SLEDAI-2K<=4, no activity in major organs/systems, no new disease activity, prednisone <=7.5mg/d and/or maintenance immunosuppressants 5) Active: all remaining assessments Antimalarials were permitted in all DAS. At each assessment, patients were stratified into 1 DAS; if >1 definition was fulfilled per assessment, the patient was stratified into the most stringent. The proportion of time patients were in a specific DAS at each assessment since cohort entry was determined. At each assessment, annual DC and IC were based on health resource use and lost workforce/non-workforce productivity over the preceding year. Resource use was costed using 2021 Canadian prices and lost productivity using Statistics Canada age-and-sex-matched wages. To examine the association between the proportion of time in a specific DAS at each assessment since cohort entry and annual DC and IC, multivariable random-effects linear regression modelling was used. Potential covariates included age at diagnosis, disease duration, sex, race/ethnicity, education, region, smoking, and alcohol use. Results 1631 patients (88.7% female, 48.9% White, mean age at diagnosis 34.5) were followed for a mean of 7.7 (SD 4.7) years (table 1, Panel A). Across 12,281 assessments, 49.3% were classified as active (table 1, Panel B). Patients spending <25% vs 75-100% of their time since cohort entry in an active DAS had lower annual DC and IC (DC $4042 vs $9101, difference -$5060, 95%CI -$5983, -$4136; IC $21,922 vs $32,049, difference -$10,127, 95% -$16,754, -$3499) (table 2, Panel B&C). In multivariable models, remission and LDA (per 25% increase in time spent in specified DAS vs active) were associated with lower annual DC and IC: remission off-treatment (DC -$1296, 95%CI -$1800, -$792; IC -$3353, 95%CI -$5382, -$1323), remission on-treatment (DC -$987, 95%CI -$1550, -$424; IC -$3508, 95%CI -$5761, -$1256), LDA-TC (DC -$1037, 95%CI -$1853, -$222; IC -$3229, 95%CI -$5681, -$778) and mLLDAS (DC -$1307, 95%CI -$2194, -$420; IC -$3822, 95%CI -$6309, $-1334) (table 3, Model B). There were no differences in costs between remission and LDA. Conclusions Remission and LDA are associated with lower costs, likely mediated through the known association of these DAS with more favourable clinical outcomes

Introduction: Signet ring cell carcinoma accounts for about one percent of all colorectal cancers. It is an aggressive subtype of adenocarcinomas with the tendency for intramural spread and peritoneal carcinomatosis. Here, we reported a middle-aged male with circumferential colonic stenosis and inconclusive histology, found to have stage 4 colorectal signet ring cell carcinoma (SRCC). Case Description/Methods: A 41-year-old male without significant past medical history was referred to a gastroenterology clinic with bright red blood per rectum. Colonoscopy showed ulcerative rectosigmoiditis with rectal bleeding, and there was stricture in the rectum, in the recto-sigmoid colon, and from anus to descending colon (Figure A). Biopsy was obtained from the stricture. The pathology revealed granulation tissue and abundant fibrinopurulent exudate showing small clusters, and individual atypical cells stained positive for CDX-2 immunostain. Unfortunately, the patient subsequently lost follow-up. Three months later, the patient was hospitalized for small bowel obstruction. CT showed markedly enlarged heterogeneous and edematous rectum, an abnormal mass within the posterior pelvis/rectum, retroperitoneal and pelvic lymphadenopathy with thickening and nodularity of the peritoneum. Biopsy was obtained from an inguinal lymph node with histological examination showing metastatic adenocarcinoma composed of poorly cohesive signet-ring cells (Figure B). Immunostains revealed that the neoplastic cells were strongly and diffusely positive for CDX2 and CK20 while negative for CK7, confirming a colorectal primary. Accordingly, the diagnosis of colorectal signet ring cell carcinoma was made.
Discussion(s): The colonoscopic findings of colorectal SRCC could be nonspecific as diffuse circumferential thickening, stricture, or ulcerations. Typical pathological features may not appear on the initial biopsy sample. Immunohistochemical testing could help increase diagnostic yield and early identification of cancer cells. Our case hallmarked the importance of close follow-up for abnormal diffuse stricture and ulcerations in the colorectal area. These lesions may need to be rebiopsied, co-screened with abdominal imaging, and undergo an immunohistochemical investigation to characterize pathology further

Background Mitochondria are intracellular organelles derived from the endosymbiosis between an a-proteobacterium and a primitive eukaryotic cell. Mitochondria thus display proinflammatory and antigenic properties, when released into the extracellular milieu. Several cross-sectional studies reported increased levels of anti-mitochondrial antibodies (AMAs) in patients with systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS). These autoantibodies also displayed correlations with the SLE disease activity index 2000 (SLEDAI-2K) and associations with various clinical manifestations (e.g. lupus nephritis, thromboses, carotid plaque). In the present study, we aim to detect AMAs against either whole organelles (AwMA), mitochondrial DNA (mtDNA) or RNA (mtRNA) through time in samples from patients included in the SLICC cohort. Methods Clinically relevant variables (e.g., sociodemographic variables, disease-specific outcomes including death and arterial vascular events (AVE)) were documented and biosamples were harvested upon patient enrolment in the SLICC cohort, as well as at each follow-up visit. AMA levels were measured by in-house direct ELISAs whereas SLE autoantibodies were detected by clinical laboratories. Healthy individuals, defined as having no known illnesses and infectious symptoms at the time of the blood draw, were recruited. 90% confidence intervals were calculated for both limits of the 95% nonparametric two-sided reference intervals for values measured in healthy donors. AMA values were segregated into 3 categories: Normal values were determined as within the inner limits of the range while values outside this range were characterized as abnormal, either lower or higher than the reference interval. (figure 1). Marginal Cox models with AMAs in 3 categories were adjusted for covariables and are presented as [hazard ratio (95% CI)]. Interactions with sex were tested in models with the AMAs as continuous variables. Results Sera from healthy individuals (n=126) or SLE patients included in the SLICC cohort, from their inclusion, up to 7 years of follow-up (n=1114 patients at baseline, 3577 samples in total). AwMA displayed lower correlations with antibodies to mitochondrial nucleic acids (versus AmtDNA: rs=0.37, and vs AmtRNA: rs=0.38), while antibodies to mitochondrial DNA or RNA shown higher correlations (rs=0.59). During our preliminary analyses on the distribution of the variables, We made intriguing observations regarding patients with AMA levels that were either lower or higher than those of healthy individuals. This information led us to categorize SLE patients as described in the methods and in figure 1. For each of the three antibodies assessed, SLE patients displayed more abnormal AMA levels at baseline than controls. The percentage of patients with higher levels of AwMA and AmtRNA increased at subsequent follow-up visits, while a slight decrease was observed for AmtDNA (figure 2). SLE patients with higher levels of AwMA showed higher risks of death [2.12 (1.18-3.83)]. It is of interest that an inverse relationship was found between AmtRNA and AVEs, with a small subset of patients with low levels of AmtRNA (n = 4), this autoantibody was associated with increased risks of this manifestation [4.46 (1.71-11.66)]. Additionally, patients with higher levels of AmtDNA and AmtRNA displayed increased risks of lupus nephritis [respectively: 3.05(2.05-4.54), and 1.56(1.12-2.18)]. Interestingly, there was an interaction with sex for AmtRNA levels effect on AVEs [males: 0.32 (0.11-0.99). Females: 1.56 (1.11-2.19)], and AmtDNA association with nephritis was only significant in female patients [4.00 (2.51-6.36)] (table 1). Conclusion These results show that AMAs display different associations with disease manifestations in various clusters of patients. These results prompt for further analyses by machine-learning in order to delineate clusters of clinical interests by adding AMAs in the routine serological assessment of SLE autoantibodies. Acknowledgements We acknowledge the contribution of the study participants, individual center support staff as well as investigators of the Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort project who for the past 20 years have made this study possible. LAY ABSTRACT The mitochondrion is a part of the cell that controls various biological mechanisms (e.g., energy supply, whether the cell should live or die, control, or produce various cellular components). They are derived, through evolution, from a microbe. Mitochondria may sometimes be jettisoned out of their host cell and subsequently elicit immune reactions - including the production of antibodies. Previous studies indicated that patients with autoimmune conditions such as systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS) have antibodies against mitochondria in their blood stream. Presence of these antibodies was associated with increased disease activity and clinical manifestations of these diseases (e.g. kidney disease, arterial vessel disease). In this study, we studied blood samples harvested by an international group dedicated to the study of SLE [i.e., the SLE International Collaborating Clinics (SLICC) cohort] and observed that patients may be clustered into groups, upon their levels of antibodies and/or sex, allowing to have a better appreciation of their risks of death, vascular events, and kidney disease. These results might lead to improved diagnosis and/or prognosis in SLE and thus, in improved care and quality of life for the people living with lupus

Objectives We previously reported in a single centre prevalent SLE cohort that antibodies against the cytokinesis-associated protein M-Phase Phosphoprotein 1 (anti-MPP-1) were associated with SLE-related cranial neuropathy (CN), a rare manifestation of neuropsychiatric SLE (NPSLE). The purpose of this study was to assess whether anti-MPP-1 is a biomarker for CN or other NPSLE manifestations using an international SLE inception cohort. Methods SLE patients fulfilling the updated 1997 ACR classification criteria for SLE were included. Anti-MPP-1 antibody testing was performed on baseline samples (within 15 months of diagnosis) or first annual assessment using an addressable laser bead immunoassay (ALBIA) with purified recombinant human protein with results expressed as median florescence units (MFU). Based on healthy controls, a dilution of >=1:500 MFU was considered positive. NPSLE manifestations occurring over the first 5 years of follow up were documented annually based on ACR case definitions using published NPSLE attribution rules1). The frequency of anti-MPP-1 positivity between patients with versus without each of the 19 NPSLE manifestations was compared using univariate logistic regression. For any NPSLE manifestations where anti-MPP-1 positivity differed between patients with versus without the manifestation, baseline demographic and clinical characteristics were compared using t-tests and twosample tests of proportions. For NPSLE manifestations associated with anti-MPP-1 positivity in the univariate analysis, multivariable logistic regression analysis using penalized maximum likelihood estimates was then performed to assess the relationship between anti-MPP-1 and the NPSLE manifestation, adjusting for age at anti-MPP-1 testing, female, White race/ethnicity, and significantly different baseline clinical characteristics. Results Seven hundred and ninety-five SLE patients were assessed; 29.8% were anti-MPP-1 positive, 88.7% female, and 52.1% White. The frequency of anti-MPP-1 positivity differed only for those with versus without CN (70.0% vs. 29.3%; odds ratio [OR] 5.16, 95%CI 1.44, 18.54) (table 1). Compared to patients without CN (n=785), patients with CN (n=10) were more likely to fulfill the ACR hematologic (difference: 23.9%, 95%CI 5.0%, 42.8%) and antinuclear antibody criteria (difference: 4.3%, 95%CI 2.9%, 5.8%) (table 2). (Table Presanted)In the multivariate analysis, anti-MPP-1 remained associated with CN (OR 5.24, 95%CI 1.44, 19.09) after adjusting for age at anti-MPP-1 testing, female, White race/ethnicity, hematologic disorder, and antinuclear antibody (table 3). Conclusion Anti-MPP-1 is a potential biomarker for CN. Although anti-MPP-1 is differentially expressed in a variety of neurological cells and tissues, the link to a pathogenic role requires further study

Introduction: Nonalcoholic fatty liver disease (NAFLD) is causing an emerging global epidemic. The global burden of disease (GBD) study estimates the burden of NAFLD in 203 countries and geographic areas across the world, providing a unique opportunity to understand the landscape of this disease.
Method(s): Prevalence, mortality, and disability-adjusted life years (DALYs) of NAFLD from 1990 to 2019 by region and country in all sex and age groups were collected from the Global Health Data Exchange (GHDx) results tool (Available from http://ghdx.healthdata.org/gbd-results-tool). DALYs are the sum of years lost due to premature death and years lived with disability. The socio-demographic index (SDI) categorizes countries and geographic areas by development (low, low-middle, middle, high-middle, and high).
Result(s): Between 1990 to 2019, the global prevalence of NAFLD increased from 10.9% to 16.6% (increased by 52.6%; linear regression beta-coefficient 0.2, P < .001). In 2019, an estimated 1.3 billion people were affected by NAFLD worldwide. Mortality attributed to NAFLD increased from 93,000 to 169,000. DALYs of NAFLD increased from 2.7 million years to 4.4 million years. Significant uptrends were observed in all SDI regions, more prominent in the middle SDI regions (Table). Changes in the prevalence of NAFLD by countries are depicted in Figure. All but three countries demonstrated an increase in the prevalence of NAFLD. More notable increases (>=10%) were mostly observed in North African and Middle Eastern countries.
Conclusion(s): NAFLD's prevalence increased by more than 50% globally from 1990 to 2019. The mortality and DALYs also increased. The increase in NAFLD prevalence is more prominent in countries with middle SDI and countries in North African and Middle Eastern regions, possibly due to changes in lifestyle in these areas over the past 30 years. (Figure Presented)

Background. Paired with other active antiretrovirals (ARVs), fostemsavir (FTR) may offer heavily treatment-experienced (HTE) people with HIV (PWH) options for continuing effective treatment. Durability and effectiveness of FTR-containing regimens in routine clinical care in the United States were assessed. Methods. Electronic health record data from the OPERA cohort were used to identify adults initiating FTR-containing regimens between 2JUL2020 (FDA approval) and 1SEP2021. Eligible PWH were followed from first FTR prescription (baseline) until FTR discontinuation, death, loss to follow up, or study end (28FEB2022). Durability was assessed as frequency of FTR discontinuation. Virologic outcomes assessed at 6 and 12 months (+/-3 months) included suppression (viral load [VL] < 50 copies/mL), virologic failure (2 consecutive VL >=200 copies/mL or 1 VL >=200 copies/ mL + FTR discontinuation within 120 days after suppression), and viral blips (1 VL >=50 copies/mL preceded and followed by VLs < 50 copies/mL). Analyses were stratified by baseline viral load (bVL < 50 copies/mL; bVL >=50 copies/mL). Results. Overall, 86 PWH initiated FTR (bVL < 50: 30; bVL >=50: 55), with median follow up of 10.8 months (IQR: 6.8, 15.3). Compared to PWH with bVL >=50, those with bVL < 50 were older and more likely to be white and have lived longer with HIV (Table 1). Over follow up, 20% discontinued FTR (Table 2). Most (82%) FTR discontinuations were switches to alternative regimens; the remaining were ARV interruptions (no ARVs for > 45 days). Among PWH with bVL < 50, most maintained suppression (6 months: 74%; 12 months: 82%; Figure). Among PWH with bVL >=50 and with follow up VL during the period assessed, 33% were suppressed at 6 months, 36% were suppressed at 12 months, and 48% achieved suppression at any time over the entire follow up (Figure). In either group, <=5 PWH experienced virologic failure or blip, though the proportion of PWH with multiple follow up VLs was low. Conclusion. Despite a heterogenous population and diverse regimens, most HTE PWH remained on FTR at study end. Most PWH with bVL < 50 remained suppressed and half of PWH with bVL >=50 achieved suppression over the entire study period. Virologic failure and blips were infrequent, although follow up was limited in this early evaluation of real-world FTR use

Background/Purpose: Knee osteoarthritis (OA) is an inflammatory disease, with a probable role for IL-1b. Calcium and urate crystals may promote OA by activating the NLRP3 inflammasome to produce IL-1b. Colchicine is a well-tolerated anti-inflammatory agent that inhibits the inflammasome and suppresses IL-1b. Studies examining the impact of colchicine on knee OA have yielded varying results, with some reporting pain relief, others improvement of inflammatory markers, and none assessing synovial effusions. We report the interim, blinded results of our ongoing colchicine trial for knee OA.
Method(s): CLOAK is a randomized, double-blind, placebo-controlled trial of colchicine (once daily for 3 months) (Figure 1). We are enrolling subjects >= 40 years of age, with symptomatic knee OA, Kellgren-Lawrence grade 2 or 3 radiographs, and willingness to forego other anti-inflammatory therapy during the trial. The primary outcome is the change in knee pain by visual analog scale (VAS) after 3 months of treatment, comparing the colchicine and placebo groups. Secondary outcomes include pre to post treatment Knee Injury and Osteoarthritis Outcome Score (KOOS), mean doses of analgesics used, and changes in plasma and peripheral blood leukocyte inflammatory markers. Patients undergo knee ultrasound (US) pre-and post-treatment to assess synovitis and effusion. We aspirate synovial fluid when appropriate, and will analyze all available blood and synovial samples after study completion.
Result(s): To date, 715 potential subjects have been contacted, 82 screened, and 71 enrolled. Among 60 who have completed the study, 51.6% are male, 60% White, 30% Black, 3.3% Asian and 6.7% other, with mean BMI of 27.6 kg/m2 and age of 66.8 years. The mean VAS pain score among all completing participants (subjects and controls combined) improved Figure 1. Flow diagram of study plan. Figure 2. Subject improvement in KOOS score from beginning to end of study, according to high or low baseline severity as measured by VAS and KOOS scores and presence of synovial effusion. by 0.98 units in the index knee, and mean KOOS scores improved for symptoms, pain, activities of daily living (ADL), sports activity, and quality of life (QOL). Overall 36 (60%) demonstrated VAS improvement (mean improvement 2.3) whereas 24 (40%) demonstrated no change or worsening. Overall, subjects whose VAS improved showed concordant improvement in the KOOS: mean symptoms by 10.5, pain by 12.4, ADL by 14.8, sports activity by 5.8 and QOL by 11.4 units. The subsets of patients with baseline VAS >=6 and baseline KOOS <=60 (i.e., more severe) showed significantly more 3-month KOOS pain improvement, even with the blinded inclusion of placebo (Figure 2). All underwent US at baseline and 3 months. Among 36 patients with VAS improvement over 3 months, 6 had baseline synovial effusions >=4 mm (in longitudinal and transverse views) and 5 of these effusions were smaller on US post-treatment and one remained stable.
Conclusion(s): The results of this blinded analysis are consistent with a potential benefit of colchicine for pain, function and effusion in subjects not taking other anti-inflammatory agents. Enrollment is ongoing and the study will be unblinded and fully analyzed after completion

Background. HIV-associated wasting (i.e., progressive, involuntary weight loss with both fat and lean tissue loss; HIVAW) is an under-appreciated AIDS-defining illness; the 2012-2018 period prevalence was reported as 18% in a recent claims study in the United States. We aimed to assess the association between incident HIVAW/ low weight and all-cause mortality in the era of modern combination antiretroviral therapy (ART). Methods. In the Observational Pharmaco-Epidemiology Research & Analysis (OPERA) cohort, PWH without (a) any prior HIVAW/low weight, (b) malignancy within 3 years, and (c) opportunistic infection within 1 year who were active in care between 2016 and 2020 were followed through death, loss to follow-up, or study end (31OCT2021). HIVAW/low weight included a wasting or low BMI/underweight diagnosis (ICD codes, title search) or BMI < 20 kg/m2. Hazard ratios (HR) and 95% confidence intervals (CI) for the association between time-dependent incident HIVAW/low weight (exposure) and all-cause mortality (outcome) were estimated with extended Cox regression models. The adjusted model included age at baseline, race, ethnicity, and time-dependent covariates (log10 viral load, Veterans Aging Cohort Study [VACS] Mortality Index score). Viral load and VACS score were included as surrogate markers for ART use and comorbidities, respectively. Linear and quadratic terms of continuous variables were included. Results. Of 67,119 PWH without prior HIVAW/low weight in OPERA, 62,314 (93%) PWH had non-missing covariate data and were included in the models; baseline characteristics did not differ between the full and model study populations (Table 1). Over a median follow-up of 45 months (interquartile range: 27, 65), there were 4,755 (8%) cases of incident HIVAW/low weight and 1,354 (2%) deaths. In the adjusted model, PWH who experienced incident HIVAW/low weight had a significantly increased risk of death over follow-up than those who did not experience HIVAW/low weight (HR: 1.96; 95% CI: 1.68, 2.27) (Table 2). Conclusion. In this analysis of 62,314 PWH in care, incident HIVAW/low weight was associated with twice the risk for all-cause mortality in the modern ART era. Particular attention needs to be paid to HIVAW/low weight among PWH to restore health and potentially reduce the risk of death

Introduction: Inborn errors of immunity are a group of primary immunodeficiency disorders caused by over 400 genetic defects. Enteropathy has been common in PID patients, which presents with chronic diarrhea, malabsorption, growth delay, iron deficiency, and failure to thrive. This article systemically reviewed the clinical presentations, treatments, and genetic defects of enteropathy observed in PIDD.
Method(s): We have reviewed published cases with the clinical diagnosis of both enteropathy and PIDD using 3 databases (Pubmed, Scopus, EMBASE). A total of 346 cases met our inclusion criteria.
Result(s): The most common enteropathy-associated PIDD is common variable immunodeficiency (32.4%), IPEX (21%), selective IgA deficiency (18.1%), and hypogammaglobulinemia (7.9%; Figure). Celiac disease (26.2%) is the most common enteropathy presentation in PIDD, followed by IPEX (20.7%), autoimmune enteropathy (6.4%), and CVID enteropathy (5.8%). Selective IgA deficiency and CD/Celiac like disease were also frequently reported. More than half of documented PIDD-related CD showed positive serology test results and histopathological findings. Eighty-eight percent of PIDD-related CD cases are responsive to a gluten-free diet. FOXP3 mutation (70) was the most common gene mutation in PIDD, followed by CTLA-4 (17), CD55 (8), NFKB1 (8), GoF-STAT1 (5), GoF-STAT3 (5), and C1-INH (4; Table)). CTLA-4 mutation was found related to CVID, hypogammaglobulinemia, and autoimmune enteropathy. NFKB1was found mainly linked to CVID. We observed frequent giardiasis (21), norovirus (3), CMV (4), Candidiasis (2), and histoplasmosis (2) infections causing enteropathy in PIDD. No significant difference in treatments of the enteropathy between PIDD and non-PIDD was noticed.
Conclusion(s): Enteropathy can be common clinical presentations in IEIs. With early recognition of clinical manifestations and enteropathy-associated gene mutation, PIDD can be diagnosed and treated timely, preventing complications and mortalities

Background. In-vitro neutralizing antibody (Ab) titers correlated with ~250 IU/ mL Spike Ig Ab level for the Delta COVID-19 variant, establishing the 2021 French and Swiss cutoff for booster guidance. In a New York City healthcare clinic where those guidelines were adopted, we aimed to quantify vaccination responses in HIV + and HIV- individuals to assess the utility of quantifying antibodies to guide booster timing. Methods. Adults who were fully vaccinated against SARS-CoV-2 virus (i.e., 2 Pfizer, 2 Moderna or 1 J&J vaccine) were included if >1 Roche SARS-CoV-2 Semi-Quant Spike Ig Ab test was performed >21 days after vaccination and before any booster (through 03DEC2021). Vaccine response was assessed at the first Ab test and considered adequate (>250 IU/mL) or inadequate (low: >=51 to <=250 IU/ mL; no response: < 51 IU/mL). The rate of Ab decline was estimated with linear regression, using all sequential Ab tests over the first 6 months between vaccination and boosting. Analyses were stratified by vaccine type, HIV status and CD4 count in HIV+ ( >200 cells/muL cutoff). Results. Out of 1979 patients, 869 completed their primary vaccinations, of whom 825 (95%) had >=1 eligible Ab test (HIV+: 512; HIV-: 313; Table). Overall, 83% had an adequate immune response to vaccination (Pfizer: 82%, Moderna: 94%, J&J: 51%), with similar findings regardless of HIV status and CD4 count (Figure 1). In those with >=2 Ab tests within six months between vaccination and boosting, Ab levels declined at a rate of 91 IU/mL per month (95% CI: -138, -44). While some variation was observed, rates of Ab decay were generally consistent across vaccine, HIV status and CD4 count strata (Figure 2). Only 1/7 breakthrough COVID-19 infections occurred post booster (6 days later Conclusion. In the pre-omicron era, primary COVID immunization with a mRNA vaccine generally yielded adequate Ab responses, although inadequate responses were observed in 19% of Pfizer, 6% of Moderna, and 49% of J&J vaccine recipients. Ab levels decreased at an average rate of 91 IU/mL per month after primary immunization. Variability in vaccine responses and Ab declines show the utility of measuring spike Ig Ab levels rather than using empiric time frames for booster guidance. Omicron-specific quantitative IgG neutralization levels must be established to inform preventative care