Descriptive evaluation of antibody responses to severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection in plasma and gingival crevicular fluid in a nursing home cohort-Arkansas, June-August 2020.

OBJECTIVE: To characterize and compare severe acute respiratory coronavirus virus 2 (SARS-CoV-2)-specific immune responses in plasma and gingival crevicular fluid (GCF) from nursing home residents during and after natural infection. DESIGN: Prospective cohort. SETTING: Nursing home. PARTICIPANTS: SARS-CoV-2-infected nursing home residents. METHODS: A convenience sample of 14 SARS-CoV-2-infected nursing home residents, enrolled 4-13 days after real-time reverse transcription polymerase chain reaction diagnosis, were followed for 42 days. After diagnosis, plasma SARS-CoV-2-specific pan-Immunoglobulin (Ig), IgG, IgA, IgM, and neutralizing antibodies were measured at 5 time points, and GCF SARS-CoV-2-specific IgG and IgA were measured at 4 time points. RESULTS: All participants demonstrated immune responses to SARS-CoV-2 infection. Among 12 phlebotomized participants, plasma was positive for pan-Ig and IgG in all 12 participants. Neutralizing antibodies were positive in 11 participants; IgM was positive in 10 participants, and IgA was positive in 9 participants. Among 14 participants with GCF specimens, GCF was positive for IgG in 13 participants and for IgA in 12 participants. Immunoglobulin responses in plasma and GCF had similar kinetics; median times to peak antibody response were similar across specimen types (4 weeks for IgG; 3 weeks for IgA). Participants with pan-Ig, IgG, and IgA detected in plasma and GCF IgG remained positive throughout this evaluation, 46-55 days after diagnosis. All participants were viral-culture negative by the first detection of antibodies. CONCLUSIONS: Nursing home residents had detectable SARS-CoV-2 antibodies in plasma and GCF after infection. Kinetics of antibodies detected in GCF mirrored those from plasma. Noninvasive GCF may be useful for detecting and monitoring immunologic responses in populations unable or unwilling to be phlebotomized.

Development and Validation of an Enzyme Immunoassay for Detection and Quantification of SARS-CoV-2 Salivary IgA and IgG.

Oral fluids offer a noninvasive sampling method for the detection of Abs. Quantification of IgA and IgG Abs in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG Abs against the prefusion-stabilized form of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein expressed in suspension-adapted HEK-293 cells. Normalization against total Ab isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 prepandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA, 95.5%; IgG, 89.7%) without compromising specificity (IgA, 99%; IgG, 97%). No cross-reactivity with endemic coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/ml and 0.30 ng/ml, respectively. Salivary IgA and IgG Abs were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary Ab titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 wk in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.

National attitudes of medical students towards mandating the COVID-19 vaccine and its association with knowledge of the vaccine.

BACKGROUND: With the introduction of the novel COVID-19 vaccine, public hesitancy is being experienced with many turning to healthcare professionals for advice. As future physicians, medical students play a critical role in the public's view of the vaccine. OBJECTIVES: To determine the attitude of U.S. medical students toward mandating the COVID-19 vaccine to healthcare workers and patients, as well as whether their knowledge of the vaccine plays a role in their view. METHODS: The authors emailed a survey link to all U.S. medical schools with request to distribute it to their medical students. The survey remained open from 02/09/2021 to 03/15/2021 and included questions to determine the attitude of the medical students toward recommending the COVID-19 vaccine, and general knowledge questions about the vaccine. Chi square, Fisher's exact test, and linear regression were conducted to determine associations between willingness to recommend the COVID-19 vaccine and general knowledge of the vaccine. RESULTS: Among the 1,899 responses from medical students representing 151 U.S. medical schools, 57.82% approved of making the COVID-19 vaccine mandatory to healthcare workers, and 16.27% approved of making it mandatory to patients. Additionally, those who tested most knowledgeable of the vaccine were less likely to approve of making the vaccine mandatory for patients (66.67% vs. 72.70). Those that tested most knowledgeable were also more likely to personally receive the vaccine (72.35% vs 62.99%) as opposed to those that tested the least knowledgeable who were less willing to personally receive the vaccine (4.12% vs 14.17%). CONCLUSIONS: The data revealed that a slight majority of medical students support a vaccine mandate toward healthcare workers while a minority of medical students support a vaccine mandate toward healthcare workers. Additionally, medical students that had relatively high knowledge of the vaccine correlated with not approving of making the vaccine mandatory for patients. However increased knowledge of the vaccine correlated with increased willingness to personally receive the vaccine.