[Basic principles of replication and immunology of SARS-CoV-2]

Nanostructures for the Prevention, Diagnosis, and Treatment of SARS-CoV-2: A Review

Scientists, doctors, engineers, and even entire societies have become aware of the seriousness of the COVID-19 infection and are taking action quickly, using all the tools from protection to treatment against coronavirus SARS-CoV-2. Especially in this sense, scientific approaches and materials using nanotechnology are frequently preferred. In this review, we focus on how nanoscience and nanotechnology approaches can be used for protective equipment, diagnostic and treatment methods, medicine, and vaccine applications to stop the coronavirus SARS-CoV-2 and prevent its spread. SARS-CoV-2, which itself can be considered as a core-shell nanoparticle, can interact with various materials around it and remain bound for variable periods of time while maintaining its bioactivity. These applications are especially critical for the controlled use of disinfection systems. One of the most important processes in the fight against coronavirus is the rapid diagnosis of the virus in humans and the initiation of isolation and treatment processes. The development of nanotechnology-based test and diagnostic kits is another important research thrust. Nanotechnological therapeutics based on antiviral drug design and nanoarchitecture vaccines have been vital. Nanotechnology plays critical roles in the production of protective film surfaces for self-cleaning and antiviral masks, gloves, and laboratory clothes. An overview of literature studies highlighting nanotechnology and nanomaterial-based approaches to combat SARS-CoV-2 is presented.

SARS-COV-2 Memory B and T Cells Profile in Mild COVID-19 Convalescents subjects

OBJECTIVES

. Antiviral adaptive immunity involves memory B-(MBC) and T-cells (MTC), however their dynamics in SARS-CoV-2 convalescents warrant further investigation.

METHODS

. In the cross-sectional and longitudinal study, we evaluated blood-derived MBC- and MTC-responses in 68 anti-spike IgG-positive mild-COVID-19 convalescents at visit 1 between 1-7 months (median 4.1 months) after disease onset. SARS-CoV-2 anti-spike IgG was performed by ELISA, MBC by SARS-COV-2 specific receptor binding domain (RBD) Elispot and Interferon gamma (IFNg), interleukin 2 (IL2) and IFNg+IL2 secreting MTC by IFNg and IL2 SARS-CoV-2 FluoroSpot. For 24 patients sampled at first visit, the IgG, MBC and MTC analysis were also performed 3 months later at second visit.

RESULTS

. Seventy two percent were both MBC- and MTC-positive, 18 % - MBC-positive and MTC-negative, and 10% - MTC-positive and MBC-negative. The peak of MBC-response level was detected at 3 months after COVID-19 onset and persisted up to 7 months post infection. A significant MTC-levels were detected one month after onset in response to S1, S2_N and SNMO peptide pools. The frequency and magnitude of MTC response to SNMO was higher than to S1 and S2_N. Longitudinal analysis demonstrated that even when specific humoral immunity declined, the cellular immunity persisted.

CONCLUSION

. Our findings demonstrate durability of adaptive cellular immunity at least for 7-months after SARS-CoV-2 infection that suggest long-lasting protection.

Reinfection risk of novel coronavirus (COVID-19): A systematic ‎review of current evidence

BACKGROUND

There is recently a concern regarding the reinfection and reactivation of previously reCoVered coronavirus disease 2019 (CoVID-19) patients.

AIM

To summarize the recent findings and reports of CoVID-19 reinfection in patients previously reCoVered from the disease.

METHODS

This study was a systematic review of current evidence conducted in August 2020. The authors studied the probable reinfection risk of novel coronavirus (CoVID-19). We performed a systematic search using the keywords in online databases. The investigation adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist to ensure the reliability and validity of this study and results.

RESULTS

We reviewed 31 studies. Eight studies described reCoVered patients with reinfection. Only one study reported reinfected patients who died. In 26 studies, there was no information about the status of the patients. Several studies indicated that reinfection is not probable and that post-infection immunity is at least temporary and short.

CONCLUSION

Based on our review, we concluded that a positive polymerase chain reaction retest could be due to several reasons and should not always be considered as reinfection or reactivation of the disease. Most relevant studies in positive retest patients have shown relative and probably temporary immunity after the reCoVery of the disease.

[Seroprevalence and SARS-CoV-2 testing in healthcare occupations]

The SARS-CoV‑2 causes a disease spectrum that includes asymptomatic and mildly symptomatic infections with subclinical manifestations but which can nevertheless still be potentially contagious. Evidence from SARS-CoV‑2 infected macaque monkeys and from studies with seasonal coronaviruses suggests that the infection is likely to produce an immunity that is protective for a certain period of time. Available test methods enable a high degree of reliability, e.g. if high-quality serological methods are combined. Although individual test results have to be interpreted with caution, serosurveillance in a tertiary eye care center and large eye research institute can reduce anxiety and provide clarity regarding the actual number of (unreported) SARS-CoV‑2 infections.