Differential Effects of the Second SARS-CoV-2 mRNA Vaccine Dose on T Cell Immunity in Naïve and COVID-19 Recovered Individuals (preprint)

The rapid development and deployment of mRNA-based vaccines against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led to the design of accelerated vaccination schedules that have been extremely effective in naïve individuals. While a two-dose immunization regimen with the BNT162b2 vaccine has been demonstrated to provide a 95% efficacy in naïve individuals, the effects of the second vaccine dose in individuals who have previously recovered from natural SARS-CoV-2 infection has not been investigated in detail. Here we characterized, SARS-CoV-2 spike-specific humoral and cellular immunity in naïve and previously infected individuals during and after two-doses of BNT162b2 vaccination. Our results demonstrate that, while the second dose increases both the humoral and cellular immunity in naïve individuals, COVID-19 recovered individuals reach their peak of immunity after the first dose. These results suggests that a second dose, according to the current standard regimen of vaccination, may be not necessary in individuals previously infected with SARS-CoV-2.Funding: Research reported in this publication was supported in part by National Cancer Institute of the NIH (5R01HD102614-02; R01CA249204 and R01CA248984) and ISMMS seed fund to EG. The authors gratefully acknowledge use of the services and facilities of the Tisch Cancer Institute supported by the NCI Cancer Center Support Grant (P30 CA196521). MS was supported by a NCI training grant (T32CA078207). This work was supported by ISMMS seed fund to JO; Instituto de Salud Carlos III, COV20-00668 to RCR; Instituto de Salud Carlos III, Spanish Ministry of Science and Innovation (COVID-19 Research Call COV20/00181) co-financed by European Development Regional Fund “A way to achieve Europe” to EP; Instituto de Salud Carlos III, Spain (COV20/00170); Government of Cantabria, Spain (2020UIC22-PUB 0019) to MLH; Instituto de Salud Carlos III (PI16CIII/00012) to PP; Fondo Social Europeo e Iniciativa de Empleo Juvenil YEI (Grant PEJ2018-004557-A) to MPE; REDInREN 016/009/009 ISCIII; This project has received funding from the European Union’s Horizon 2020 research and innovation programme VACCELERATE under grant agreement No [101037867] to JO.Conflict of Interest: AB declares the filling of a patent application relating to the use of peptide pools in whole blood for detection of SARS-CoV-2 T cells (pending). The other authors declare no competing interests.Ethical Approval: The study protocols for the collection of clinical specimens from individuals with and without SARS-CoV-2 infection were reviewed and approved by Hospital La Paz, Hospital 12 de Octubre, Hospital Gregorio Marañón, IIS-Fundación Jimenez Díaz, Hospital Universitario Marqués de Valdecilla-IDIVAL and Hospital Puerta de Hierro Clinical Research Ethics Committee (CEIm), and Mount Sinai Hospital Institutional Review Board (IRB).

Differential effects of the second SARS-CoV-2 mRNA vaccine dose on T cell immunity in naive and COVID-19 recovered individuals (preprint)

The rapid development and deployment of mRNA-based vaccines against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led to the design of accelerated vaccination schedules that have been extremely effective in naive individuals. While a two-dose immunization regimen with the BNT162b2 vaccine has been demonstrated to provide a 95% efficacy in naive individuals, the effects of the second vaccine dose in individuals who have previously recovered from natural SARS-CoV-2 infection has been questioned. Here we characterized SARS-CoV-2 spike-specific humoral and cellular immunity in naive and previously infected individuals during full BNT162b2 vaccination. Our results demonstrate that the second dose increases both the humoral and cellular immunity in naive individuals. On the contrary, the second BNT162b2 vaccine dose results in a reduction of cellular immunity in COVID-19 recovered individuals, which suggests that a second dose, according to the current standard regimen of vaccination, may be not necessary in individuals previously infected with SARS-CoV-2.

The Age Again in The Eye of The Covid-19 Storm: Evidence-Based Decision Making. (preprint)

Background: One hundred million of contagions, more than 2 million deaths and less than one year of COVID-19 have changed our lives and our health management systems forever. Ageing is known to be one of the significant determinants for COVID-19 severity. Two main reasons underlie this: immunosenescence and age correlation with main COVID-19 comorbidities such as hypertension or dyslipidaemia. This study has two aims. The first is to obtain cut-off points for laboratory parameters that can help us in clinical decision-making. The second one is to analyse the effect of pandemic lockdown on epidemiological, clinical, and laboratory parameters concerning the severity of the COVID-19. For these purposes, 257 of SARSCoV2 inpatients during pandemic confinement were included in this study. Moreover, 584 case records from a previously analysed series, were compared with the present study data. Results: Concerning the characteristics of lockdown series, mild cases accounted for 14.4%, 54.1% were moderate and 31.5%, severe. There were 32.5% of home contagions, 26.3% community transmissions, 22.5% nursing home contagions, and 8.8% corresponding to frontline worker contagions regarding epidemiological features. Age >60 and male sex are hereby confirmed as severity determinants. Equally, higher severity was significantly associated with higher IL6, CRP, ferritin, LDH, and leukocyte counts, and a lower percentage of lymphocyte, CD4 and CD8 count. Comparing this cohort with a previous 584-cases series, mild cases were less than those analysed in the first moment of the pandemic and dyslipidaemia became more frequent than before. Age, lymphocyte count and LDH had similar distributions at both moments. IL-6, CRP and LDH values above 69 pg/mL, 97 mg/L and 328 U/L respectively, as well as a CD4 T-cell count below 535 cells/μL, were the best cut-offs predicting severity since these parameters offered reliable areas under the curve. Conclusion: Age, sex and dyslipidaemia together with selected laboratory parameters on admission can help us predict COVID-19 severity and, therefore, make clinical and resource management decisions. Demographic features associated with lockdown could affect the homogeneity of the data and the robustness of the results.

Sars-CoV-2 Detection by Self-Testing: A Method that Makes Surveillance Programs Possible and Effective (preprint)

Background: The simplicity and low cost of rapid point-of-care tests greatly facilitate large-scale population testing, which can contribute to controlling the spread of the COVID-19 virus.Methods: Between April and May 2020, the applicability of a self-testing strategy for SARS-CoV2 detection was evaluated in a population-based, cross-sectional study in Cantabria, Spain. For the self-testing strategy, participants received the necessary material for blood self-collection and performance of a rapid antibodies test using lateral flow immunoassay at home without the supervision of healthcare personnel.Findings: A total of 1,022 participants were enrolled. The vast majority of participants correctly performed the COVID-19 self-test the first time (91.3% [95% IC 89.4-92.9]). Only a minority of participants (0.7%) needed the help of healthcare personnel, and 6.9% required a second kit delivery, for a total valid test result in 96.9% of the participants. Incorrect use of the self-test did not depend on the educational level, age over 65 years, or housing area. Prevalence of IgG antibodies against SARS-CoV2 for subjects with a valid rapid test result was 3.1% (95% IC 2.2-4.4), similar to the seroprevalence result obtained using a conventional approach carried out by healthcare professionals.Interpretation: A strategy of COVID-19 self-testing could be applied as a screening tool in surveillance programs.Funding Statement: No funding.Declaration of Interests: The authors report no relevant conflict of interest ordisclosures relevant to this manuscript.Ethics Approval Statement: The Ethics Committee of investigation of Cantabria approved this study (code 2020.176) and written informed consent was obtained from all participants.

COVID-19 in Spain: age, Interleukin-6, C Reactive Protein and lymphocytes as key clues from a multicentre retrospective study (preprint)

Background. SARS-CoV-2 infection has widely spread to the hugest public health challenge to date, COVID-19 pandemic. Different fatality rates among countries are probably due to non-standardized records being carried out by local health authorities. Spanish case-fatality rate is 11.94%, far higher to those reported in Asia or by other European countries. A multicenter retrospective study was performed of demographic, clinical, laboratory and immunological features of 574 Spanish COVID-19 hospitalized patients and their outcomes. The use of use of renin-angiotensin system blockers was also analyzed as a risk factor. Results. In this study, 27.7% of cases presented a mild curse, 42% a moderate one and for 30.3% of cases, the course was severe. Ages ranged from 18 to 98 (average 63.2). Fifty eight percent (58.9%) of patients were male. Interleukin 6 was higher as severity increased. On the other hand, CD8 lymphocyte count was significantly lower as severity grew and subpopulations CD4, CD8, CD19 and NK showed concordant lowering trends. Severity-related natural killer percent descents were evidenced just within aged cases. A significant severity-related decrease of CD4 lymphocytes was found in males. The use of renin-angiotensin system blockers was associated with moderate or mild disease courses. Conclusions. Age and age-related comorbidities, such as dyslipidaemia, hypertension or diabetes, determined more frequent severe forms of the disease in this study than in previous literature cohorts. Our cases are older than those so far reported and clinical course of the disease is found to be impaired by age. Immunosenescence might be therefore a suitable explanation for immune system effectors severity-related hampering. Adaptive immunity would go exhausted and a huge ineffective and almost deleterious innate response would account for COVID-19 severity. Renin-angiotensin system blockers treatment in hypertensive patients has a protective effect as regarding COVID-19 severity.

Can Climatic Factors Explain the Differences in COVID-19 Incidence and Severity Across the Spanish Regions?: An Ecological Study (preprint)

Background: Environmental factors play a central role in seasonal epidemics. SARS-CoV-2 infection in Spain has shown a heterogeneous geographical pattern This study aimed to assess the influence of several climatic factors on the infectivity of SARS-CoV-2 and the severity of COVID-19 among the Spanish Autonomous Communities (AA.CC.).Methods: Data on coronavirus infectivity and severity of COVID-19 disease, as well as the climatic variables were obtained from official sources (Ministry of Health and Spanish Meteorological Agency, respectively). To assess the possible influence of climate on the development of the disease, data on ultraviolet radiation (UVR) were collected during the months before the start of the pandemic. To analyze its influence on the infectivity of SARS-CoV-2, data on UVR, temperature, and humidity were obtained from the months of highest contagiousness to the peak of the pandemic.Results: From October 2019 to January 2020, mean UVR was significantly related not only to SARS-CoV-2 infection (cumulative incidence -previous 14 days- x105 habitants, rho=-0.0,666; p=0.009), but also with COVID-19 severity, assessed as hospital admissions (rho=-0.626; p=0.017) and ICU admissions (rho=-0.565; p=0.035). Besides, temperature (February: rho=-0.832; p<0.001 and March: rho=-0.904; p<0.001), was the main climatic factor responsible for the infectivity of the coronavirus and directly contributed to a different spread of SARS-CoV-2 across the Spanish regions.Conclusions: Climatic factors may partially explain the differences in COVID-19 incidence and severity across the different Spanish regions. The knowledge of these factors could help to develop preventive and public health actions against upcoming outbreaks of the disease.