Effects of antivirals on patients with COVID-19 breakthrough

BACKGROUND

Antivirals have been given widely for patients with COVID-19 breakthrough in Asian countries, creating a "black market" for unapproved and unprescribed medications. More evidence is needed to clarify the benefits of antivirals in these settings.

METHODS

We conducted a random-sampling retrospective cohort study at a general hospital in Vietnam. We recruited patients with mild-to-moderate COVID-19 breakthrough who were given either standard of care (SoC) alone or SoC + antiviral. Primary outcome was residual respiratory symptoms that lasted > 7 days. Secondary outcome was long COVID-19, diagnosed by specialized physicians. We used logistic regression to measure odds ratio (OR), in addition to a sensitivity and subgroup analyses to further explore the results.

RESULTS

A total of 142 patients (mean age 36.2 ± 9.8) were followed. We recorded residual symptoms in 27.9% and 20.3% of the SoC and SoC + antiviral group, while the figures for long COVID-19 were 11.8% and 8.1%, respectively. Antiviral use was not significantly associated with lower the risks of residual symptoms (OR = 0.51, 95% CI: 0.22-1.20, p = 0.12) or long COVID-19 (OR = 0.55, 95% CI: 0.16-1.90, p = 0.35). The sensitivity and subgroup analyses did not show any significant differences between the study groups (all p > 0.05).

CONCLUSION

Antivirals were not associated with faster resolution of respiratory symptoms or lower risks of long COVID-19. Further studies should focus on different antivirals to confirm their effects on different sub-populations. Meanwhile, antivirals should only be used in very high-risk patients to avoid excessive costs and harms.

Breakthrough invasive fungal infection in patients with myeloid malignancy receiving posaconazole tablet prophylaxis: clinical features, risk factors, and posaconazole profiles

Posaconazole (PSC) delayed-release tablet prophylaxis is the standard of care for preventing invasive fungal infection (IFI) in patients with acute myeloid leukemia undergoing myelosuppressive chemotherapy. The clinical features, risk factors, and PSC profiles of breakthrough IFI (bIFI) in patients receiving PSC tablet prophylaxis were investigated. A single-center retrospective cohort study was conducted, including adult patients with myeloid malignancy who received prophylactic PSC tablets while undergoing chemotherapy from June 2016 to June 2021. Logistic regression analysis was used to identify risk factors for breakthrough IFI. A receiver operating characteristic curve was used to predict the relationship between PSC trough level at steady-state and breakthrough IFI. A total of 434 patients with myeloid malignancy who received PSC tablets were screened. Ten patients with bIFI were compared with 208 non-IFI patients. There were four proven and six probable IFI cases, nine due to Aspergillus and one due to Fusarium species. The bIFI patients had higher in-hospital mortality (30.0%) than the non-IFI patients (1.9%; P < 0.001). History of allogeneic hematopoietic stem cell transplantation (OR 6.27; 95% CI 1.63-24.09), prolonged neutropenia ≥ 28 days (OR 4.33; 95% CI 1.20-15.70), and low plasma PSC concentration < 0.7 μg/mL (OR 16.33; 95% CI 4.15-64.26) were risk factors for bIFI. The optimal cut-off value of plasma PSC concentration predicting bIFI was 0.765 μg/mL (sensitivity, 60.0%; specificity, 91.3%; area under the curve, 0.746). bIFI was not uncommon in patients with myeloid malignancy receiving PSC tablets prophylaxis and associated with poor outcomes. Therapeutic drug monitoring may still be necessary, even in patients receiving PSC tablets.

The impact of COVID-19 vaccines on the Case Fatality Rate: The importance of monitoring breakthrough infections

Objectives

This study aimed to test the behavior of the case fatality rate (CFR) in a mixed population of vaccinated and unvaccinated individuals by illustrating the role of both the effectiveness of vaccines in preventing deaths and the detection of infections among both the vaccinated (breakthrough infections) and unvaccinated individuals.

Methods

We simulated three hypothetical CFR scenarios that resulted from a different combination of vaccine effectiveness in preventing deaths and the efforts in detecting infections among both the vaccinated and unvaccinated individuals.

Results

In the presence of vaccines, the CFR depends not only on the effectiveness of vaccines in preventing deaths but also on the detection of breakthrough infections. As a result, a decline in the CFR may not imply that vaccines are effective in reducing deaths. Likewise, a constant CFR can still mean that vaccines are effective in reducing deaths.

Conclusions

Unless vaccinated people are also tested for COVID-19 infection, the CFR loses its meaning in tracking the pandemic. This shows that unless efforts are directed at detecting breakthrough infections, it is hard to disentangle the effect of vaccines in reducing deaths from the probability of detecting infections on the CFR.