ABSTRACT
Background: The COVID-19 pandemic has disproportionately impacted people who use illicit drugs and misuse prescription drugs (PWUD), including increased risk for infection with SARS-CoV-2, clinical COVID-19, and poorer health outcomes. The reasons for this disparity are multifactorial and may include numerous social and structural factors. Yet, little is known about COVID-19 testing and vaccinations among PWUD. Methods: This cross-sectional study was conducted in Miami, Florida, USA between March and September 2021 with the support of the National Institutes of Health Rapid Acceleration of Diagnostics-Underserved Populations (RADx-UP) initiative. Participants had to be 18 years of age and older and willing to be tested for COVID-19. Recruitment included convenience and snowball sampling. The RADx-UP survey (available at https://radx-up.org/) was administered via telephone. Results: A total of 931 participants were enrolled in the study;median age was 59 (53, 64) years, 65.5% were Black, 32.1% Hispanic, and 69.2% had a household income of less than $15,000 in 2019. Nearly a third of participants (32.6%) used drugs. Additionally, 37.6% smoked cigarettes, and 5.2% consumed alcohol for four or more days per week. Twenty percent of participants had never been tested for COVID-19. Of those who reported ever being tested, 14.1% reported ever being positive for SARS-CoV-2, with 67.2% of those having moderate-to-severe symptoms and 26.7% reporting being hospitalized due to COVID-19. Overall, 19 (2.2%) participants tested positive for SARS-CoV-2 at the time of the study, which was more frequent among PWUD than drug non-users (4.2% vs. 1.2%, respectively;p=0.004). PWUD, compared to drug non-users, were less likely to be vaccinated against COVID-19 (66.7% vs. 75.2% for any one dose, respectively;p=0.006). Compared to drug non-users, PWUD had 3.62 (95% CI: 1.41, 9.30;p=0.008) times higher odds of being positive for SARS-CoV-2 based on rt-PCR testing at the time of interview, and 0.66 (95% CI: 0.49, 0.89;p=0.006) times lower odds of being at least partially vaccinated against COVID-19. Conclusion: People who use drugs may be at increased risk of contracting SARS-CoV-2 and developing COVID-19, which could be in part related to lower vaccination rates in addition to comorbidities and lifestyle factors. Testing and immunization plans are needed that are specific for PWUD, considering the barriers and facilitators of this population.
ABSTRACT
Study Objectives: While almost all adults vaccinated with the SARS-CoV-2 mRNA vaccine become positive for the IgG antibody (Ab) targeting the spike protein of SARS-CoV-2 within a week of their second dose, correlates of protection for SARS-CoV-2 are not fully understood. Therefore, the primary purpose of this study was to attempt to quantify the percentage of SARS-CoV-2 neutralizing antibodies (nAb) that develop after dose 2 vaccinations and also identify any factors that might affect the timing and degree of nAb production. Methods: A fluorescence immunoassay analyzer was used to quantify the percent of SARS-CoV-2 antibodies capable of blocking the spike protein at its receptor binding domain (RBD) for attachment to ACE-2 receptors. Seventy residents and staff of an assisted living facility ranging in age from 23 to 100 years were enrolled. Fingerstick blood samples were measured at seven days and 21 days following the 2nd dose of the Pfizer-BioNTech mRNA vaccine. Based on prior research, nAb measurements <30% were considered to be inadequate protection and therefore delineated as nAb negative. Results: Except for a 58 year old (yo) man taking daily prednisone for asthma and another 55 yo man with hypothyroidism (treated with levothyroxine), 100% of the 34 persons <70 were positive for neutralizing Ab (assays with >30% nAb) on day 7 after the 2 nd vaccine dose. However, among the 37 patients older than 70 years, the percent of persons positive for nAb (>30%) on Day 7 diminished with age. Only half of those 71-80 yo, 33% of those 81-90 yo and 11% of those >90 yo were positive for nAb. Two weeks later, however, the percentages among those tested had increased to 83%, 71%, and 50% for those respective age groups. Also, one week after the second vaccine dose, the average neutralizing Ab% measurement (%nAb) among the various age groups under the age of 50 years ranged from 95 to 100% while age group averages were borderline or inadequate for those older than 70 years. Nevertheless, 21 days after the second dose, the average %nAb measurement had become 91% for those 61 to 70 years of age, 75% for those 71-80, and 55% for those 81-90. For the eight persons over 90 years of age, the average %nAb was 35% and half of those persons (n=4) had no detectable nAb, either at day 7 or day 21. No persons had significant declines in the %nAb measurements and the majority sustained or improved their %nAb between Day 7 and Day 21. Conclusions: Escalating age and immunomodulating medications and conditions can impact the timing and degree of neutralizing Ab produced following SARS-CoV-2 mRNA vaccination. Most persons under the age of 90 years were considered to be “positive” for protective levels of nAb within three weeks following the 2nd dose of the SARS-CoV-2 mRNA vaccine. On-going investigations involve evaluations of the duration and sustained degree of positive nAb findings, as well as external validation of the tool used in this current research.
ABSTRACT
Study Objective: The focus of this study was to document the timing of humoral antibody (IgM, IgG) development following SARS-CoV-2 mRNA vaccinations and assess factors influencing antibody (Ab) production. Methods: Ranging in age 23-100 years, 77 persons living or working in an assisted living facility were tested for IgG and IgM just prior to receiving their 1st dose of the Pfizer-BioNTech mRNA vaccine on 01/17/2021. Re-retesting occurred on Day 14, Day 21 (before dose 2), Day 28 and Day 42 (7 days and 21 days after dose 2). Medical histories, including underlying conditions and medications, were collected confidentially. Testing involved point-of-care lateral flow chromatography devices (under emergency use authorization as reported in our previous research on PCR+, humoral Ab- persons) using fingerstick samples. The lateral flow assay antigens included a recombinant nucleocapsid protein and a spike protein (S1) conjugated with colloid gold. Readings were recorded 15 min. after obtaining blood samples. Results: On the day of dose 1, one person had a faint IgM reading (and a known past history of COVID-19) and 3 others demonstrating detectable Ab were asymptomatic and had no known prior illness. None of these four persons were PCR + at the time of assay and their Ab profiles all further evolved following vaccination. Consistent with the original Pfizer clinical trial, on Day 14, 27 (69%) of the 39 persons <70 years old (yo) already were demonstrating a degree of new Ab production while 84% of the 38 persons >70 had no detectable Ab. However, by Day 21, just prior to receiving the second dose of vaccine, 100% of persons <60 yo had detectable Ab except for two persons taking immunosuppressants. In each successive decade of age, a progressively smaller % of persons showed Ab production (eg, among those >90 yo, 80% tested Ab negative). Seven days after the second dose, however, 100% of persons <80 yo had become Ab positive (except 2 taking immunosuppressants). Whereas only 89% of those in their 80s (n=18) and 78% of those in their 90s had IgG detected seven days after their second dose, by day 42, only two persons remained Ab negative (one taking immunosuppressants and the other was a 93 yo). Semi-quantitative results indicated strong Ab responses for 100% of those <80 yo on Day 42. Also, as previously demonstrated, the point of care chromatography device used for the assays had reproducible results and there was persistent Ab detection in all persons once they had turned positive. Conclusions: Age and immunosuppressant conditions impact the timing and degree of Ab production following mRNA vaccination. Contrasted with our prior Ab study findings regarding native COVID-19 disease in which some persons < 50 yo manifesting milder disease do not generate IgG/IgM, the current study did demonstrate that younger persons uniformly have a rapid onset of strong IgG development after mRNA vaccination, even before their second dose. While very elderly persons and those taking immunosuppressants generally had undetectable IgG production after the first dose of vaccine, almost everyone developed strong responses, regardless of age, within a week following dose two. Antibody development became even more evident and robust 21 days after the second dose of the vaccine.