Objective We performed a systematic review and meta-analysis of epidemiological data of injuries in professional male football. Method Forty-four studies have reported the incidence of injuries in football. Two reviewers independently extracted data and assessed trial quality using the Strengthening the Reporting of Observational Studies in Epidemiology statement and Newcastle Ottawa Scale. Studies were combined in a pooled analysis using a Poisson random effects regression model. Results The overall incidence of injuries in professional male football players was 8.1 injuries/1000 hours of exposure. Match injury incidence (36 injuries/1000 hours of exposure) was almost 10 times higher than training injury incidence rate (3.7 injuries/1000 hours of exposure). Lower extremity injuries had the highest incidence rates (6.8 injuries/1000 hours of exposure). The most common types of injuries were muscle/tendon (4.6 injuries/1000 hours of exposure), which were frequently associated with traumatic incidents. Minor injuries (1–3 days of time loss) were the most common. The incidence rate of injuries in the top 5 European professional leagues was not different to that of the professional leagues in other countries (6.8 vs 7.6 injuries/1000 hours of exposure, respectively). Conclusions Professional male football players have a substantial risk of sustaining injuries, especially during matches.

The virological and immunological effects of the immunomodulatory drugs used for COVID-19 remain unknown. We evaluated the impact of interleukin (IL)-6 blockade with tocilizumab on SARS-CoV-2 viral kinetics and the antibody response in patients with COVID-19. Prospective cohort study in patients admitted with COVID-19. Serial nasopharyngeal and plasma samples were measured for SARS-CoV-2 RNA and S-IgG/N-IgG titers, respectively. 138 patients with confirmed infection were included; 76 (55%) underwent IL-6 blockade. Median initial SOFA (p = 0•016) and SARS-CoV-2 viral load (p<0•001, Mann-Whitney-Wilcoxon test) were significantly higher among anti-IL-6 users. Patients under IL-6 blockade showed delayed viral clearance in the Kaplan-Meier curves (HR 0•35 [95%CI] [0•15–0•81], log-rank p = 0•014), but an adjusted propensity score matching model did not demonstrate a significant relationship of IL-6 blockade with viral clearance (HR 1•63 [0•35–7•7]). Cox regression showed an inverse association between SARS-CoV-2 RNA clearance and the initial viral load (HR 0•35 [0•11–0•89]). Patients under the IL-6 blocker showed shorter median time to seropositivity, higher peak antibody titers, and higher cumulative proportion of seropositivity in the Kaplan Meier curves (HR 3•1 [1•9–5] for S-IgG; and HR 3•0 [1•9–4•9] for N-IgG; log-rank p<0•001 for both). However, no significant differences between groups were found in either S-IgG (HR 1•56 [0•41–6•0]) nor N-IgG (HR 0•96 [0•26–3•5]) responses in an adjusted propensity score analysis. Our results suggest that in patients infected with SARS-CoV-2, IL-6 blockade does not impair the viral specific antibody responses. Although a delayed viral clearance was observed, it was driven by a higher initial viral load. The study supports the safety of this therapy in patients with COVID-19. Instituto de salud Carlos III (Spain).

The interdependencies of viral replication and the host immune response in patients with coronavirus disease 2019 (COVID-19) remain to be defined. We investigated the viral determinants of antibody response, the predictors of nonseroconversion, and the role of antibodies on viral dynamics. This was a prospective study in patients hospitalized with COVID-19 that was microbiologically confirmed by real-time polymerase chain reaction (RT-PCR). Serial nasopharyngeal and oropharyngeal swabs and plasma samples were obtained for measuring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and antibodies (total and S-IgG/N-IgG), respectively. Of 132 patients included, 99 (75%) showed positive antibody titers after a median (Q1–Q3) of 11 (8–14) days. The median (Q1–Q3) follow-up was 74.5 (63.0–87.0) days. In an adjusted linear regression model, time to seropositivity was inversely associated with peak log SARS-CoV-2 viral load (P = .009) and positively with time to viral clearance (P = .004). Adjusted predictors of S-IgG levels were time to viral clearance (P < .001), bilateral lung infiltrates on admission (P = .011), and the time-dependent SARS-CoV-2 RNA (P < .001) and SARS-CoV-2 RNA area under the curve (P = .001). Thirty-three (25%) patients showed undetectable antibody titers. Patients who did not seroconvert had higher cycle threshold values of RT-PCR (38.0 vs 28.0; P < .001), had shorter time to viral clearance (3.0 vs 41.0; P < .001), and were more likely to have SARS-CoV-2 only detected on fecal samples (P < .001). Nonseroconvertors had also lower levels of blood inflammatory biomarkers on admission and lower disease severity. Viral replication determines the magnitude of antibody response to SARS-CoV-2, which, in turn, contributes to viral clearance. COVID-19 patients who do not seroconvert exhibit a differential virological and clinical profile.

Background: We evaluated a standardized interferon-γ (IFN-γ) release assay (IGRA) for detection of T-cell immune response after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination. Methods: This prospective study included patients with coronavirus disease 2019 (COVID-19) with different severity of illness and follow-up (FU), vaccinated subjects, and healthy unvaccinated persons. SARS-CoV-2 T-cell response was measured using a specific quantitative IGRA in whole blood (Euroimmun, Germany) and TrimericS-IgG and neutralizing antibodies with validated serological platforms. Positivity of reverse transcription–polymerase chain reaction or vaccination was considered as the reference standard. Results: A total of 239 individuals were included (152 convalescent, 54 vaccinated, and 33 uninfected unvaccinated). Overall sensitivity, specificity, and positive- and negative-predictive values (95% confidence interval) of the IGRA were 81.1% (74.9–86%), 90.9% (74.5–97.6%), 98.2% (94.5–99.5%), and 43.5% (31.8–55.9%), respectively. All vaccinated SARS-CoV-2-naive subjects had positive IGRA at 3 months. In convalescent subjects the magnitude of IFN-γ responses and IGRA accuracy varied according to disease severity and duration of FU, with the best performance in patients with severe COVID-19 at 3 months and the worst in those with mild disease at 12 months. The greatest contribution of IGRA to serological tests was observed in patients with mild disease and long-term FU (incremental difference, 30.4%). Conclusions: The IGRA was a reliable method of quantifying T-cell response after SARS-COV-2 infection or vaccination. In convalescent patients, the sensitivity is largely dependent on disease severity and time since primary infection. The assay is more likely to add clinical value to serology in patients with mild infections.