Immunocompromised patients are disproportionately impacted by severe disease, hospitalization, and mortality associated with coronavirus disease 2019 (COVID-19). To optimize the management of these patients in clinical practice, we convened an expert panel to review current evidence on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine responses and severe COVID-19 in immunocompromised populations. We identified four main immunocompromised groups-solid organ transplant recipients, patients receiving allogeneic hematopoietic stem cell transplantation or chimeric antigen receptor (CAR) T cell therapy, patients treated for hematologic malignancies, and patients treated for inflammatory diseases-who mount suboptimal humoral responses to SARS-CoV-2 vaccination and are at increased risk of severe COVID-19-related outcomes. A wide range of risk factors were associated with reduced vaccine responses and/or poor outcomes, most commonly older age, comorbidities, and the type and number of immunosuppressive therapies. We believe that early identification and close monitoring of these at-risk patients, plus regular booster vaccinations, prophylactic monoclonal antibody therapy, non-pharmacologic prevention measures, prompt antiviral treatment, and other risk mitigation strategies, are critical to protect against SARS-CoV-2 infection and severe COVID-19.

Prior to the introduction of COVID-19 vaccines, patients with severe mental illness (SMI) were at greater risk of COVID-19-related outcomes than the general population. It is not yet clear whether COVID-19 vaccines have reduced the risk gap. We systematically searched nine international databases and three Chinese databases to identify relevant studies from December 2020 to December 2023 to compare the risk of COVID-19-related outcomes for SMI patients to those without SMI after vaccination. Random effects meta-analysis was performed to estimate the pooled odds ratio (OR) with 95% confidence intervals (CI). Subgroup analysis, sensitivity analysis, and publication bias analysis were conducted with R software 4.3.0. A total of 11 observational studies were included. Compared with controls, SMI patients were associated with a slightly increased risk of infection (pooled OR = 1.10, 95% CI, 1.03-1.17, I2 = 43.4%), while showing a 2-fold higher risk of hospitalization (pooled OR = 2.66, 95% CI, 1.13-6.22, I2 = 99.6%), even after both groups have received COVID-19 vaccines. Limited evidence suggests a higher mortality risk among SMI patients compared to controls post vaccination, but the findings did not reach statistical significance. SMI patients remain at increased risk compared to their peers in COVID-19-related outcomes even after vaccination. Vaccination appears an effective approach to prevent severe COVID-19 illness in SMI patients, and actions should be taken by healthcare providers to improve vaccination coverage in these vulnerable groups.

Myocarditis is the most salient serious adverse event following messenger RNA-based Covid-19 vaccines. The highest risk is observed after the second dose compared to the first, whereas the level of risk associated with more distant booster doses seems to lie in between. We aimed to assess the relation between dosing interval and the risk of myocarditis, for both the two-dose primary series and the third dose (first booster). This matched case-control study included 7911 cases of myocarditis aged 12 or more in a period where approximately 130 million vaccine doses were administered. Here we show that longer intervals between each consecutive dose, including booster, may decrease the occurrence of vaccine-associated myocarditis by up to a factor of 4, especially under age 50. These results suggest that a minimum 6-month interval might be required when scheduling additional booster vaccination.

The coronavirus disease 2019 (COVID-19) pandemic has posed a major public health concern worldwide. Patients with comorbid conditions are at risk of adverse outcomes following COVID-19. Solid organ transplant recipients with concurrent immunosuppression and comorbidities are more susceptible to a severe COVID-19 infection. It could lead to higher rates of inpatient complications and mortality in this patient population. However, studies on COVID-19 outcomes in liver transplant (LT) recipients have yielded inconsistent findings.

To evaluate the impact of the COVID-19 pandemic on hospital-related outcomes among LT recipients in the United States.

We conducted a retrospective cohort study using the 2019-2020 National Inpatient Sample database. Patients with primary LT hospitalizations and a secondary COVID-19 diagnosis were identified using the International Classification of Diseases, Tenth Revision coding system. The primary outcomes included trends in LT hospitalizations before and during the COVID-19 pandemic. Secondary outcomes included comparative trends in inpatient mortality and transplant rejection in LT recipients.

A total of 15720 hospitalized LT recipients were included. Approximately 0.8% of patients had a secondary diagnosis of COVID-19 infection. In both cohorts, the median admission age was 57 years. The linear trends for LT hospitalizations did not differ significantly before and during the pandemic (P = 0.84). The frequency of in-hospital mortality for LT recipients increased from 1.7% to 4.4% between January 2019 and December 2020. Compared to the pre-pandemic period, a higher association was noted between LT recipients and in-hospital mortality during the pandemic, with an odds ratio (OR) of 1.69 [95% confidence interval (CI): 1.55-1.84), P < 0.001]. The frequency of transplant rejections among hospitalized LT recipients increased from 0.2% to 3.6% between January 2019 and December 2020. LT hospitalizations during the COVID-19 pandemic had a higher association with transplant rejection than before the pandemic [OR: 1.53 (95%CI: 1.26-1.85), P < 0.001].

The hospitalization rates for LT recipients were comparable before and during the pandemic. Inpatient mortality and transplant rejection rates for hospitalized LT recipients were increased during the COVID-19 pandemic.

Combination antiviral therapy may be helpful in the treatment of SARS-CoV-2 infection; however, no clinical trial data are available, and combined use of direct-acting antivirals (DAA) and monoclonal antibodies (mAb) has been reported only anecdotally. To assess the cooperative effects of dual drug combinations in vitro, we used a VERO E6 cell-based in vitro system with the ancestral B.1 or the highly divergent BQ.1.1 virus to test pairwise combinations of the licensed DAA, including nirmatrelvir (NRM), remdesivir (RDV) and the active metabolite of molnupiravir (EIDD-1931) as well the combination of RDV with four licensed mAbs (sotrovimab, bebtelovimab, cilgavimab, tixagevimab; tested only with the susceptible B.1 virus). According to SynergyFinder 3.0 summary and weighted scores, all the combinations had an additive effect. Within DAA/DAA combinations, paired scores with the B.1 and BQ.1.1 variants were comparable. In the post hoc analysis weighting synergy by concentrations, several cases of highly synergistic scores were detected at specific drug concentrations, both for DAA/DAA and for RDV/mAb combinations. This was supported by in vitro confirmation experiments showing a more than a linear shift of a drug-effective concentration (IC50) at increasing concentrations of the companion drug, although the effect was prominent with DAA/DAA combinations and minimal or null with RDV/mAb combinations. These results support the cooperative effects of dual drug combinations in vitro, which should be further investigated in animal models before introduction into the clinic.

Coronavirus disease 2019 (COVID-19) and malaria, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Plasmodium parasites, respectively, share geographical distribution in regions where the latter disease is endemic, leading to the emergence of co-infections between the two pathogens. Thus far, epidemiologic studies and case reports have yielded insufficient data on the reciprocal impact of the two pathogens on either infection and related diseases. We established novel co-infection models to address this issue experimentally, employing either human angiotensin-converting enzyme 2 (hACE2)-expressing or wild-type mice, in combination with human- or mouse-infective variants of SARS-CoV-2, and the P. berghei rodent malaria parasite. We now show that a primary infection by a viral variant that causes a severe disease phenotype partially impairs a subsequent liver infection by the malaria parasite. Additionally, exposure to an attenuated viral variant modulates subsequent immune responses and provides protection from severe malaria-associated outcomes when a blood stage P. berghei infection was established. Our findings unveil a hitherto unknown host-mediated virus-parasite interaction that could have relevant implications for disease management and control in malaria-endemic regions. This work may contribute to the development of other models of concomitant infection between Plasmodium and respiratory viruses, expediting further research on co-infections that lead to complex disease presentations.

Solid organ transplant recipients are at high risk of severe infection with SARS-CoV-2 compared with the general population. However, factors associated with COVID-19-related severity in this population are still insufficiently explored in the literature.

To examine which health conditions and immunosuppressive drugs for preventing graft rejection are associated with the risk of COVID-19-related hospitalization in solid organ transplant recipients.

Using the French National Health Data System, this cohort study assessed patients of any age who received transplants between their date of birth and entry into the cohort on February 15, 2020. The cohort was followed up between February 15, 2020, and July 31, 2022.

Immunosuppressive drugs, including steroids, and health conditions (age, sex, and comorbidities).

The main outcome was hospitalization for COVID-19, defined by main diagnostic International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes. Factors associated with the outcome were identified with a nonconditional logistic regression. Confounding by indication was controlled using a multivariable model with adjustment for individual confounders. Each transplanted organ was examined separately.

Overall, 60 456 participants (median [IQR] age, 59 [47-67] years; 63.7% male) were included in the study, of whom 41 463 (68.6%) had kidney transplants, 14 464 (23.9%) had liver transplants, 5327 (8.8%) had heart transplants, and 2823 (4.6%) had lung transplants. Among them, 12.7% of kidney transplant recipients, 6.4% of liver transplant recipients, 12.9% of heart transplant recipients, and 18.0% of lung transplant recipients were hospitalized for COVID-19. In kidney transplant recipients, steroids (adjusted odds ratio [AOR], 1.60; 95% CI, 1.49-1.73) and mycophenolic acid (AOR, 1.37; 95% CI, 1.25-1.51) were associated with a high risk of hospitalization. In liver transplant recipients, tacrolimus (AOR, 0.77; 95% CI, 0.61-0.98) was associated with a decreased risk, and steroids (AOR, 1.60; 95% CI, 1.38-1.86) and mycophenolic acid (AOR, 1.61; 95% CI, 1.37-1.90) were associated with an increased risk of hospitalizations. In heart transplant recipients, cyclosporine (AOR, 0.67; 95% CI, 0.47-0.94) was associated with a decreased risk, and steroids (AOR, 1.42; 95% CI, 1.11-1.82), mycophenolic acid (AOR, 1.29; 95% CI, 1.02-1.64), sirolimus (AOR, 2.71; 95% CI, 1.20-6.09), and everolimus (AOR, 1.24; 95% CI, 1.01-1.51) were associated with an increased risk of hospitalization. Only steroids (AOR, 1.72; 95% CI, 1.19-2.48) were associated with a high risk of COVID-19 hospitalization in lung transplant recipients.

This study suggests that mycophenolic acid, sirolimus, and steroids are associated with an increased risk of COVID-19-related hospitalization in solid organ transplant recipients. These results should be considered by clinicians treating transplant recipients and may help inform epidemic-related decisions for this population in the future.

Knowing the duration of effectiveness of coronavirus disease 2019 (COVID-19) booster doses is essential to providing decision-makers with scientific arguments about the frequency of subsequent injections. We estimated the level of protection against COVID-19-related hospitalizations (Omicron BA.4-BA.5) over time after vaccination, accounting for breakthrough infections.

In this nationwide case-control study, all cases of hospitalizations for COVID-19 identified in the comprehensive French National Health Data System between June 1, 2022, and October 15, 2022, were matched with up to 10 controls by year of birth, sex, department, and an individual COVID-19 hospitalization risk score. Conditional logistic regressions were used to estimate the level of protection against COVID-19-related hospitalizations conferred by primary and booster vaccination, accounting for history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

A total of 38 839 cases were matched to 377 653 controls; 19.2% and 9.9% were unvaccinated, respectively, while 68.2% and 77.7% had received ≥1 booster dose. Protection provided by primary vaccination reached 45% (95% CI, 42%-47%). The incremental effectiveness of booster doses ranged from 69% (95% CI, 67%-71%; ≤2 months) to 22% (95% CI, 19%-25%; ≥6 months). Specifically, the second booster provided an additional protection compared with the first ranging from 61% (95% CI, 59%-64%; ≤2 months) to 7% (95% CI, 2%-13%; ≥4 months). Previous SARS-CoV-2 infection conferred a strong, long-lasting protection (51% ≥20 months). There was no incremental effectiveness of a second booster among individuals infected since the first booster.

In the era of Omicron BA.4 and BA.5 predominance, primary vaccination still conferred protection against COVID-19 hospitalization, while booster doses provided an additional time-limited protection. The second booster had no additional protection in case of infection since the first booster.

During the COVID-19 pandemic, EPI-PHARE, a scientific group in pharmaco-epidemiology created by the French National Agency for the Safety of Medicines and Health Products (ANSM) and the French National Health Insurance (Cnam), has reoriented its work program to enlighten health authorities in this health crisis. By exploiting massive and complex data of the French Health Data System (SNDS) from the beginning of the first lockdown in France in March 2020, we were able to publish numerous results on the use, benefits and risks of medicines, on the risk factors of COVID-19 before and after vaccination, and on the benefits and risks of COVID-19 vaccines. Our results were widely taken into account by the French health authorities and allowed them to take informed decision in this pandemic situation in order to ensure the health of the population.

Chronic kidney disease affects more than 800 million people worldwide and often progresses to end-stage renal disease, which requires maintenance dialysis. Patients receiving dialysis are at higher risk for severe respiratory infections, including SARS-CoV-2 (the causative agent of COVID-19). In addition, many patients who receive dialysis also receive immunosuppressive treatments for conditions such as systemic vasculitis, systemic lupus erythematosus, or malignancies. Many studies have shown that while mRNA COVID-19 vaccines induce some level of immune response in patients receiving dialysis, the magnitude of response is often lower than that of healthy individuals, and responses rapidly wane. Importantly, the risk of COVID-19-related hospitalization and mortality for patients receiving dialysis is 4- to 8-fold higher compared with the general population. In this article, we summarize recent immunogenicity and real-world outcomes of COVID-19 mRNA vaccination among patients receiving dialysis, with a focus on the 3-dose extended primary series and additional (fourth) doses.

No study has yet investigated if a severe SARS-CoV-2 infection represents a marker of an undiagnosed cancer. This population-based study, using the SNDS database, identified from 02/15/2020 to 08/31/2021, 41,302 individuals hospitalized in intensive care unit due to SARS-CoV-2 (ICU-gr) and 713,670 control individuals not hospitalized for SARS-CoV-2 (C-gr). Individuals were matched according to year of birth, sex and French department. The cancer incidence was compared in the two groups during the follow-up period (index date-12/31/2021), using Cox proportional hazards models adjusted on matching variables, socioeconomic characteristics and comorbidities. In the ICU-gr, 2.2% (n = 897) was diagnosed with a cancer in the following months, compared to 1.5% (n = 10,944) in the C-gr. The ICU-gr had a 1.31 higher risk of being diagnosed with a cancer following hospital discharge compared to the C-gr (aHR 1.31, 95% CI 1.22-1.41). A global similar trend was found when competing risk of death was taken into account (aHR 1.25, 95% CI 1.16-1.34). A significant higher risk was found concerning renal (aHR 3.16, 95% CI 2.33-4.27), hematological (aHR 2.54, 95% CI 2.07-3.12), colon (aHR 1.72, 95% CI 1.34-2.21), and lung (aHR 1.70, 95% CI 1.39-2.08) cancers. This suggests that a severe SARS-CoV-2 infection may represent a marker of an undiagnosed cancer.

Background: The COVID-19 epidemic has disrupted care and access to care in many ways. It was accompanied by an excess of cardiovascular drug treatment discontinuations. We sought to investigate a deeper potential impact of the COVID-19 epidemic on antihypertensive drug treatment disruptions by assessing whether the epidemic induced some changes in the characteristics of disruptions in terms of duration, treatment outcome, and patient characteristics. Methods: From March 2018 to February 2021, a repeated cohort analysis was performed using French national health insurance databases. The impact of the epidemic on treatment discontinuations and resumption of antihypertensive medications was assessed using preformed interrupted time series analyses either on a quarterly basis. Results: Among all adult patients on antihypertensive medication, we identified 2,318,844 (18.7%) who discontinued their antihypertensive treatment during the first blocking period in France. No differences were observed between periods in the characteristics of patients who interrupted their treatment or in the duration of treatment disruptions. The COVID-19 epidemic was not accompanied by a change in the proportion of patients who fully resumed treatment after a disruption, neither in level nor in trend/slope [change in level: 2.66 (-0.11; 5.42); change in slope: -0.67 (-1.54; 0.20)]. Results were similar for the proportion of patients who permanently discontinued treatment within 1 year of disruption [level change: -0.21 (-2.08; 1.65); slope change: 0.24 (-0.40; 0.87)]. Conclusion: This study showed that, although it led to an increase in cardiovascular drug disruptions, the COVID-19 epidemic did not change the characteristics of these. First, disruptions were not prolonged, and post-disruption treatment outcomes remained unchanged. Second, patients who experienced antihypertensive drug disruptions during the COVID-19 outbreak were essentially similar to those who experienced disruptions before it.