Widely heterogeneous humoral and cellular immunity after mild SARS-CoV-2 infection in a homogeneous population of healthy young men.

BACKGROUND: We studied humoral and cellular responses against SARS-CoV-2 longitudinally in a homogeneous population of healthy young/middle-aged men of South Asian ethnicity with mild COVID-19. METHODS: In total, we recruited 994 men (median age: 34 years) post-COVID-19 diagnosis. Repeated cross-sectional surveys were conducted between May 2020 and January 2021 at six time points - day 28 (n = 327), day 80 (n = 202), day 105 (n = 294), day 140 (n = 172), day 180 (n = 758), and day 280 (n = 311). Three commercial assays were used to detect anti-nucleoprotein (NP) and neutralizing antibodies. T cell response specific for Spike, Membrane and NP SARS-CoV-2 proteins was tested in 85 patients at day 105, 180, and 280. RESULTS: All serological tests displayed different kinetics of progressive antibody reduction while the frequency of T cells specific for different structural SARS-CoV-2 proteins was stable over time. Both showed a marked heterogeneity of magnitude among the studied cohort. Comparatively, cellular responses lasted longer than humoral responses and were still detectable nine months after infection in the individuals who lost antibody detection. Correlation between T cell frequencies and all antibodies was lost over time. CONCLUSION: Humoral and cellular immunity against SARS-CoV-2 is induced with differing kinetics of persistence in those with mild disease. The magnitude of T cells and antibodies is highly heterogeneous in a homogeneous study population. These observations have implications for COVID-19 surveillance, vaccination strategies, and post-pandemic planning.

Remote Mentorship Using Video Conferencing as an Effective Tool to Strengthen Laboratory Quality Management in Clinical Laboratories: Lessons From Cambodia.

BACKGROUND: Providing professional development opportunities to staff working in clinical laboratories undergoing quality improvement programs can be challenged by limited funding, particularly in resource-limited countries such as Cambodia. Using innovative approaches such as video conferencing can connect mentors with practitioners regardless of location. This study describes and evaluates the methods, outputs, and outcomes of a quality improvement program implemented in 12 public hospital laboratories in Cambodia between January 2018 and April 2019. The program used mixed intervention methods including both in-person and remote-access training and mentorship. METHODS: Training outputs were quantified from the activity reports of program trainers and mentors. Program outcomes were measured by pre- and postimplementation audits of laboratory quality management system conformity to international standards. Variations in improved outcomes were assessed in relation to the time spent by laboratory personnel in video conference training and mentoring activity. An additional cross-sectional comparison described the difference in final audit scores between participating and nonparticipating laboratories. RESULTS: Laboratories significantly improved their audit scores over the project period, showing significant improvement in all sections of the ISO 15189 standard. Pre- and postaudit score differences and laboratory personnel participation time in remote mentoring activities showed a strong monotonic relationship. Average input per laboratory was 6,027±2,454 minutes of participation in video conference activities with mentors. Audit scores of participating laboratories were significantly higher than those of laboratories with no quality improvement program. CONCLUSION: Laboratories improved significantly in ISO 15189 conformity following structured laboratory quality management systems training supported by remote and on-site mentoring. The correlation of laboratory participation in video conference activities highlights the utility of remote video conferencing technology to strengthen laboratories in resource-limited settings and to build communities of practice to address quality improvement issues in health care. These findings are particularly relevant in light of the COVID-19 pandemic.