Preliminary data suggest that inactivated vaccine-induced neutralizing antibodies againstSARS-CoV-2 decrease at six months after vaccination. Observational, unpublished data alsoindicate that vaccine effectiveness against Covid-19 wanes over time. Thus, theinvestigators aimed to determine the reactogenicity, safety, and immunogenicity of ahomologous or heterologous booster of SARS-CoV-2 vaccines among people already immunizedwith an inactivated SARS-CoV-2 vaccine. The study focuses on the elderly population andhealthcare workers.

Randomized, open, multicenter, collaborative and adaptive non-inferiority trial toevaluate the immunogenicity and reactogenicity of the heterologous vaccination schedulesmade up of the combination of vaccines available in Argentina (Sputnik-V, AstraZeneca,Sinopharm and Moderna); and to compare the immunogenicity and reactogenicity ofheterologous and homologous vaccination schedules.

Stress is underpinned by a biological reaction of the organism allowing the production ofenergy to respond to a change in the environment (or stressor). Stress reaction isexpressed in behavioural, cognitive, emotional and physiological terms. This biologicalresponse is non-specific because it is the same regardless of the stressor. Its evolutionover time has been conceptualised by Hans Selye (1956) in the General Adaptation Syndrome(GAS) which comprises three successive phases. (i) The first phase, known as the alarmphase, corresponds to the activation of all biological mechanisms according to a trendregulation, allowing a rapid response to the stressor. (ii) The second phase ofresistance which adjusts the stress response to the intensity of the perceived aggressionaccording to a constant regulation. (iii) When the aggression disappears, a recoveryphase dominated by the return of the parasympathetic brake allows a return to homeostasis(eustress).The "primum movens" of all pathologies is therefore the inability of the individual toadapt his stress response in duration and/or intensity to the course of the phases of theGAS (distress). The perception of not being in control of the situation contributes tothe perceived stress and constitutes a well-established risk of distress. It is a riskfactor for the emergence of burnout. It induces a biological cost called allostatic cost.Allostasis is a concept that characterizes the process of restoring homeostasis in thepresence of a physiological challenge. The term "allostasis" means "achieving stabilitythrough change", and refers in part to the process of increasing sympathetic activity andcorticotropic axis to promote adaptation and restore homeostasis. Allostasis works wellwhen allostasis systems are initiated when needed and turned off when they are no longerrequired. Restoring homeostasis involves effective functioning of the parasympatheticsystem. However, when the allostasis systems remain active, such as during chronicstress, they can cause tissue burnout and accelerate pathophysiological processes.The perception of uncontrollability depends on the stress situation, the psychologicaland physiological characteristics of the subject and his or her technical skills inresponding to the stressors of the situation. In particular, subjects with a high levelof mindfulness are more accepting of uncontrollability and less likely to activate thestress response.The COVID-19 pandemic situation is a situation characterized by many uncertainties aboutthe individual, family and work environment and the risk of COVID infection. Healthcareworkers, like the military, are high-risk occupations that are particularly exposed tothese uncertainties in the course of their work and continue to work in an uncertainsituation. These professionals are described as a population at risk ofoccupational/operational burnout that the level of burnout operationalises. Thisancillary study in a population of civilian and military non-healthcare workers willcomplement the study conducted among military health care workers. It will make itpossible to isolate the specificity of each profession (civilian or military, healthcarepersonnel or not) with regard to the risk of burnout in the COVID context.The objective of this project is to evaluate the impact of the perception of non-controlin the operational burnout of experts in their field of practice and to study thepsychological and physiological mechanisms mediating the relationship between thesubject's characteristics, perceived non-control and burnout.

A total of 300 healthy volunteers between the ages of 18 and 80 with no previous historyof COVID-19 will be entered into the study and will receive IPV by injection on Day 1.Blood specimens collected pre-inoculation will be tested for cross-reactivity topoliovirus and SARS-CoV-2 by Western blot. An additional specimen will be collected onDay 28 post-inoculation and, likewise tested for cross-reactivity to poliovirus andSARS-CoV-2.The number of subjects with an immune response to SARS-CoV-2 antigens followinginoculation with IPV will be summarized.

This is a phase I, randomized, placebo-controlled, double-blind study, to evaluate safetyand immunogenicity of a recombinant SARS-CoV-2 vaccine (CHO cell) in Chinese healthypopulation aged 18 years and older. After randomization, the trial for each subject willlast for approximately 13 months. Screening period is 1 week prior to randomization (Day-7 to Day -1), and each dose of either SARS-CoV-2 vaccine (CHO Cell) or placebo will begiven intramuscularly (IM) on Day 0 and Day 14 for a two-dose regimen, or on Day 0, Day14, and Day 28 for a three-dose regimen. Subjects who are ≥18 years old and ≤ 59 yearsold will be enrolled in adult group, and healthy elderly population who are >59 years oldwill be enrolled in elderly group. After adult group completes the follow-up 7 days afterfirst vaccination, elderly group will be recruited.

A multicenter, randomized, double-blind, placebo-controlled trial for hospitalizedmoderate COVID-19 patients

A randomized, double-blind, placebo-controlled international multicenter clinical trialdesign will be adopted. A total of 29,000 subjects aged 18 years and above are planned tobe recruited, including 750 subjects aged 18-59 years and 250 subjects aged 60 years andabove in China; 21,000 subjects aged 18-59 years and 7,000 subjects aged 60 years andabove will be recruited outside China. Safety and immunogenicity will be evaluated amongthe Chinese subjects, and efficacy, immunogenicity and safety will be evaluated among thesubjects outside China. Among them, 750 subjects aged 18-59 and 250 subjects aged 60 andabove from outside China and all subjects from China will be selected as theimmunogenicity subgroup for immunogenicity bridging study. The IgG levels of SARS-COV-2neutralizing antibody and RBD protein binding antibody will be detected by blood samplingbefore vaccination, 14 days and 6 months after full course of vaccination to evaluate theimmunogenicity and immune persistence.

Long-term neurocognitive and psychiatric consequences of COVID-19 remain mostly unknownto date. It has been reported that coronaviruses cause direct central nervous systeminfection (Needham et al. 2020). Besides that, new or worsening cognitive impairmentcommonly occurs and persists in survivors of intensive care unit (ICU) stay (Hosey &Needham. 2020). The purpose of our study is to search and describe the cognitive andpsychiatric long-term consequences of COVID-19 on patients who have been discharged fromcritical care units. This is an ambidirectional cohort study, that attempts to followadults discharged from critical Care Units Adults due to COVID-19 up to 12 months afterdischarge, to evaluate the presence of cognitive impairment, linguistic and phonationfunction, depression, fatigue, functional gastroenterological symptoms, anxiety, or posttraumatic disorder, and performance in activities of daily living and physical responseto exercise as well.

Evaluation of the efficacy of the AstrazenicaCovid 19 vaccine to develop IgG antibody andits level based on th12 weeks program. Also to follow the changes of markers ofcoagulation (D-dimer) after vaccination compared to the basic level. A cardiologyconsultant will follow D-Dimer results to be managed properly if there is a need. As itis expected to receive Sinopharm vaccine there will be comparison between results of thetwo types of vaccine. To our knowledge this will be the first study done on Egyptianpopulation.

The study is designed to assess whether allergic rhinitis and allergen immunotherapyaffect the humoral response to SARS-CoV-2 Vaccination in adults. This is a prospectivestudy enrolling a total of approximately 120 subjects, 18-55 years old.