Comparing the survival of adult inpatients with COVID-19 during the wild-type, Delta, and Omicron emergence.

OBJECTIVE: This study aimed to compare the survival experience of adult inpatients with laboratory-confirmed COVID-19 during the first three waves (wild type, Delta, and Omicron) of the pandemic in Mexico. STUDY DESIGN: A retrospective and nationwide study was conducted. METHODS: Data from 229,311 participants were analyzed using the Kaplan-Meier method, and estimates per each pandemic wave were obtained. A multivariate Cox proportional hazard regression model was fitted, and hazard ratios (HRs) and 95% confidence intervals (CIs) were computed. RESULTS: The overall mortality rate was 49.1 per 1000 person-days. Heterogeneous survival rates were observed during the analyzed emergences (log-rank test, P < 0.001), and the lowest survival functions were computed during the Omicron variant dominance. In multiple analyses and after adjusting by host characteristics and COVID-19 vaccination status, cases occurring during the Delta (vs wild type: HR = 1.03, 95% CI 1.01-1.05) and Omicron emergence were at increased risk for a fatal in-hospital outcome (HR = 1.17, 95% CI 1.13-1.22). CONCLUSIONS: Our results suggest variant-related differences in the survival rates of hospitalized patients with laboratory-positive COVID-19. When compared with the wild-type virus, lower rates were observed during the Delta and Omicron emergence.

[Survival in pediatric patients with pneumonia in coronavirus disease 2019]

Background: A segment of children and adolescents with coronavirus disease 2019 (COVID-19) develops pneumonia and published evidence regarding its prognostic factors in this specific population is scarce. Objective: To characterize the survival of children and adolescents hospitalized for pneumonia related to COVID-19, as well as to evaluate prognostic factors for disease's outcomes. Material and methods: A cohort study was performed in Mexico and data from hospitalized children and adolescents with COVID-19 related pneumonia were analyzed. We used the Kaplan-Meier method to estimate survival functions and 95% confidence intervals (95% CI), as well as Cox proportional-hazards regressions to evaluate the association of the evaluated exposures with the outcomes of disease. Results: A total of 1423 patients were recruited for a follow-up of 15,188 person-days and the overall rate of in-hospital mortality (n = 208) was 13.7 per 1000 person-days. The survival function was 96.5% (95% CI 95.2-97.4%) and 69.3% (95% CI 63.9-74.0) of hospital stay, respectively. In multiple analysis, the history of immunosuppression was associated with an increased risk of a fatal outcome (hazard ratio [HR] = 2.70, IC 95% 1.38-5.30). Conclusions: We characterized the survival of a large cohort of children and adolescents with COVID-19 related pneumonia. The presented findings suggest that minors with a history of immunosuppression and pneumonia have an increased risk of fatal outcome.

[Obesity, CKD and gender on the 30-day in-hospital mortality risk in adults with COVID-19]

Background: The coronavirus disease 2019 (COVID-19) pandemic is a serious health problem. The Mexican adult population has a high prevalence of obesity and chronic diseases that increase the risk of dying from this disease. Objective: To identify comorbidities predicting the risk of mortality at 30 days in hospitalized adult subjects with positive laboratory COVID-19 test and to evaluate the interaction between chronic diseases and gender. Material and methods: A retrospective cohort study was conducted in 2020, in a western region of the Mexican Pacific. Data from 51,135 hospitalized patients with positive COVID-19 test were analyzed and were retrieved from a normative system for the epidemiological surveillance of viral respiratory diseases (SINOLAVE, according to its initials in Spanish). Death within the first 30 days from hospital admission was the main outcome and risk ratios (RR) with 95% confidence intervals (95% CI) were calculated. Results: The overall mortality rate was 49.6% and most of the comorbidities analyzed were associated with a higher risk of death. There were significant interactions between gender and obesity (p = 0.003) and chronic kidney disease (p = 0.019). The effect of obesity on the risk of a fatal outcome varied by gender: female, RR = 1.04 (95% CI 1.03-1.07);male, RR = 1.07 (95% CI: 1.06-1.09). Conclusions: A high mortality was observed among the hospitalized patients analyzed and statistically significant factors associated with their risk were identified (gender, obesity, and kidney disease).

First-generation BNT162b2 and AZD1222 vaccines protect from COVID-19 pneumonia during the Omicron variant emergence.

OBJECTIVE: This study aimed to identify factors predicting pneumonia in adults with coronavirus disease 2019 (COVID-19) during the Omicron variant (B.1.1.529) emergence. We also evaluated, in fully vaccinated (BNT162b2 or AZD1222) individuals, if the time (<6 or ≥6 months) elapsed since the last shot was received was associated with the risk of severe illness. STUDY DESIGN: A retrospective cohort study was conducted in Mexico. METHODS: Data from 409,493 were analyzed, and risk ratios (RRs) and 95% confidence intervals (CIs) were computed through generalized linear models. RESULTS: We documented a total of 3513 COVID-19 pneumonia cases (69.5 per 100,000 person-days). In multiple analyses, a protective effect was observed in vaccinated adults (RR = 0.996, 95% CI 0.995-0.997). Male gender, increasing age, and smoking were associated with a greater risk of pneumonia. Individuals with chronic comorbidities (pulmonary obstructive disease, type 2 diabetes mellitus, arterial hypertension, kidney disease, and immunosuppression) were also at higher risk. Among fully vaccinated subjects (n = 166,869), those who had received the last shot at 6 more months were at increased risk for developing pneumonia (RR = 1.002, 95% CI 1.001-1.003). CONCLUSIONS: Our results suggest that the first-generation BNT162b2 and AZD1222 vaccines reduce the risk of COVID-19 pneumonia during the Omicron emergence. We also found that adults with longer interval from the administration of the second shot to illness onset were at increased risk of severe manifestations.

Decreased risk of COVID-19 pneumonia in children and adolescents during the Delta variant emergence.

OBJECTIVES: This study aimed to evaluate factors associated with the risk of COVID-19 pneumonia in children (aged <10 years) and adolescents (aged 10-19 years) before (March 2020-April 2021) and during (May-July 2021) the Delta (B.1.617.2) variant emergence. STUDY DESIGN: A retrospective and nationwide cohort study was conducted in Mexico. METHODS: Data from 26,961 laboratory-confirmed cases of COVID-19 were analyzed. Risk ratios (RRs) and 95% confidence intervals (CIs) were used to evaluate the association of the evaluated exposures with the risk of COVID-19 pneumonia. RESULTS: The overall incidence rate of pneumonia was 23.0 per 10,000 person-days, and it was lower during the Delta variant emergence (30.3 vs. 9.4 person-days, p < 0.001). In multiple analysis, a decreased risk of pneumonia was observed among those cases occurring in May 2021 or later (vs. March 2020-April 2021, RR = 0.98, 95% CI 0.97-0.99) and among older patients (RRper year = 0.998, 95% CI 0.996-0.998). Other comorbidities (namely, obesity, chronic kidney disease, diabetes mellitus, immunosuppression, or malignant tumors) were associated with an increased risk of severe COVID-19 manifestations. CONCLUSIONS: Our findings suggest that during the Delta variant emergence, children and adolescent patients were at reduced risk of COVID-19 pneumonia in Mexico. Further research is needed to identify factors determining the observed scenario.

Survival in adult pneumonia inpatients fulfilling suspected COVID-19 criteria and baseline negative RT-qPCR.

OBJECTIVES: The objective of this study was to evaluate the survival experience of suspicion COVID-19 hospitalized patients with pneumonia and negative baseline reverse-transcription quantitative polymerase chain reaction (RT-qPCR) test results. STUDY DESIGN: We conducted a nationwide retrospective cohort study in Mexico. METHODS: Adult pneumonia inpatients fulfilling suspected COVID-19 criteria, and hospital entry from March to August 2020, were enrolled. The Kaplan-Meier method was to use to compare survival estimates among patients with negative RT-qPCR nasopharyngeal or oropharyngeal swabs and those with a baseline positive test. RESULTS: Data from 64,624 individuals fulfilling suspected COVID-19 criteria were analyzed and 1.6% of them had negative RT-qPCR tests. The overall mortality rate was higher among laboratory-positive patients (48.5% vs. 34.2%, P < 0.001) and, at any given threshold, the survival estimates were higher among RT-qPCR-negative pneumonia inpatients. CONCLUSIONS: The pathogenic mechanism of COVID-19 remains poorly understood and suspected cases with pneumonia and negative laboratory results represent a major challenge for healthcare systems. Our findings suggest that RT-qPCR-negative inpatients may have an improved disease prognosis, but the in-hospital mortality was still high among them. However, further research is needed to clarify the clinical and epidemiological implications of our results.

Performance of the case definition of suspected influenza before and during the COVID-19 pandemic.

OBJECTIVE: This study aimed to evaluate the performance, before and during the COVID-19 pandemic, of the case definition of suspected influenza used in community surveillance in Mexico. METHODS: A cross-sectional analysis of a cohort study was performed and cases that met the suspected case criteria (n = 20,511) and that had laboratory-conclusive evidence (quantitative real-time polymerase chain reaction) to confirm or discard influenza virus infection were analysed. RESULTS: A high sensitivity and modest specificity were documented, which later decreased during the COVID-19 outbreak, as well as its diagnostic accuracy. However, no significant differences were observed in the area under the receiver operating characteristics curve among the analysed periods. CONCLUSIONS: The evaluated case definition remains to be a cost-effective alternative for identifying patients who may benefit from influenza-specific antiviral drugs, even during the global COVID-19 outbreak.

Predictors of severe symptomatic laboratory-confirmed SARS-CoV-2 reinfection.

OBJECTIVE: The aim of the study was to evaluate factors predicting severe symptomatic laboratory-confirmed (via Reverse transcription polymerase chain reaction, RT-PCR polymerase chain reaction) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection. STUDY DESIGN: This is a nationwide retrospective cohort study that was conducted in Mexico. METHODS: Data from 258 reinfection cases (at least 28 days between both episodes onset) were analyzed. We used risk ratios (RRs) and 95% confidence intervals (CIs) to evaluate predictors of severe (dyspnea requiring hospital admission) secondary SARS-CoV-2 infection. RESULTS: The risk of severe disease was 14.7%, and the observed overall fatality rate was 4.3%. Patients with more serious primary disease were more likely to develop severe symptoms (39.5% vs. 5.5%, P < 0.001) during reinfection. In multiple analysis, factors associated with an increased risk of severe symptomatic SARS-CoV-2 reinfection were increasing age (RRper year = 1.007, 95% CI = 1.003-1.010), comorbidities (namely, obesity [RR = 1.12, 95% CI = 1.01-1.24], asthma [RR = 1.26, 95% CI = 1.06-1.50], type 2 diabetes mellitus [RR = 1.22, 95% CI = 1.07-1.38]), and previous severe laboratory-confirmed coronavirus disease 2019 (RR = 1.20, 95% CI = 1.03-1.39). CONCLUSIONS: To the best of our knowledge, this is the first study evaluating disease outcomes in a large set of laboratory-positive cases of symptomatic SARS-CoV-2 reinfection, and factors associated with illness severity were characterized. Our results may contribute to the current knowledge of SARS-CoV-2 pathogenicity and to identify populations at increased risk of a poorer outcome after reinfection.

Predictors of laboratory-positive COVID-19 in children and teenagers.

OBJECTIVE: The aim of the study was to identify factors predicting laboratory-positive coronavirus disease 2019 (COVID-19) in pediatric patients with acute respiratory symptoms. STUDY DESIGN: We conducted a cross-sectional analysis of a prospective cohort study. METHODS: Data from 1849 individuals were analyzed. COVID-19 was confirmed (reverse transcription-quantitative polymerase chain reaction) in 15.9% of patients, and factors predicting a positive test result were evaluated through prevalence odds ratios and 95% confidence intervals. RESULTS: Increasing age, personal history of obesity, and household contact with a case were found to be associated, in the multiple regression model, with increased odds of a positive test result. Young patients residing in areas with higher population sizes, as well as those with severe respiratory symptoms, were less likely to be laboratory confirmed. CONCLUSIONS: Early identification and isolation of children and teenagers with suggestive symptoms of COVID-19 is important to limit viral spread. We identified several factors predicting the laboratory test result. Our findings are relevant from a public health policy perspective, particularly after the restart of in-person academic activities.

Survival in adult inpatients with COVID-19.

BACKGROUND: The mortality of the coronavirus disease 2019 (COVID-19) pandemic is high, and data regarding its prognosis are scarce. We aimed to assess the survival experience and determining factors in adult inpatients with laboratory-confirmed COVID-19. METHODS: We conducted a nationwide and retrospective cohort study. Data from 66,123 individuals were analyzed using the Kaplan-Meier method, and a multivariate Cox proportional hazard regression model was fitted. RESULTS: The 7-day survival was 72.2% and went to 47.6%, 35.0%, and 23.9% on days 15, 21, and 30 of hospital stay, respectively. In the multiple analysis, factors associated with an increased risk of dying were male gender, age, pneumonia at hospital admission, immunosuppression, and personal history of chronic non-communicable diseases. Reduced risk of a fatal outcome was observed among patients with asthma history. CONCLUSIONS: To the best of our knowledge, this is the largest study analyzing the survival probability in a large subset of Latin-American adults with COVID-19, in whom the disease burden has been high. Our results contribute to achieving a better understanding of disease evolution.

[Performance of the case definition of suspected influenza before and during the COVID-19 pandemic]. / Desempeño de la definición de caso sospechoso de influenza antes y durante la pandemia por COVID-19.

OBJECTIVE: This study aimed to evaluate the performance, before and during the COVID-19 pandemic, of the case definition of suspected influenza used in community surveillance in Mexico. METHODS: A cross-sectional analysis of a cohort study was perfomed and cases that met the suspected case criteria (n = 20,511) and that had laboratory-conclusive evidence (quantitative real-time polymerase chain reaction) to confirm or discard influenza virus infection, were analysed. RESULTS: A high sensitivity and modest specificity were documented, which later decreased during the COVID-19 outbreak, as well as its diagnostic accuracy. However, no significant differences were observed in the area under the receiver operating characteristics curve among the analysed periods. CONCLUSION: The evaluated case definition remains to be a cost-effective alternative for identifying patients who may benefit from influenza-specific antiviral drugs, even during the global COVID-19 outbreak.