Assessing the Burden of Dengue during the COVID-19 Pandemic in Mexico.

The transmission of the dengue virus in Mexico has historically been high, and its burden during the COVID-19 pandemic is currently not well understood. Our objective was to assess the burden of dengue-related disability-adjusted life years (DALYs) between 2020 and 2022. We conducted a cross-sectional analysis of databases resulting from an epidemiological surveillance of vector-borne diseases and computed DALYs using the protocol of the Global Burden of Disease (GBD) study 2019. Our results showed that there were 218,807 incident cases of dengue during the study period, resulting in 951 deaths. The calculated DALYs (and their 95% confidence intervals) were 8121 (7897-8396), 4733 (4661-4820), and 8461 (8344-8605) in 2020, 2021, and 2022, respectively. The DALY rates (per 100,000) were 6.5 (6.3-6.6), 3.8 (3.7-3.9), and 6.7 (6.6-6.8), respectively. The rates for 2020 and 2022 were similar to the historical mean (6.4, p = 0.884), whereas the rate for 2021 was lower than the mean. Premature mortality (years of life lost, YLL) contributed to 91% of the total burden. Our findings suggest that dengue fever remained a significant cause of disease burden during the COVID-19 pandemic, especially in terms of premature mortality.

Predictors of Recurrent Laboratory-Confirmed Symptomatic SARS-CoV-2 Infections in a Cohort of Healthcare Workers.

BACKGROUND: Repeated SARS-CoV-2 infections are plausible and related published data are scarce. We aimed to identify factors associated with the risk of recurrent (three episodes) laboratory-confirmed symptomatic SARS-CoV-2 infections. METHODS: A retrospective cohort study was conducted, and 1,700 healthcare workers were enrolled. We used risk ratios (RR) and 95% confidence intervals (CI) to evaluate the factors associated with symptomatic SARS-CoV-2 infections. RESULTS: We identified 14 participants with recurrent illness episodes. Therefore, the incidence rate was 8.5 per 10,000 person months. In a multiple-model study, vaccinated adults (vs. unvaccinated, RR = 1.05 [1.03-1.06]) and those with a severe first illness episode (vs. mild disease, RR = 1.05 [1.01-1.10]) were at increased risk for repeated symptomatic SARS-CoV-2 reinfections. Increasing age showed a protective effect (per each additional year of age: RR = 0.98 [0.97-0.99]). CONCLUSIONS: Our results suggest that recurrent SARS-CoV-2 infections are rare events in adults, and they seem to be determined, partially, by vaccination status and age.

Reemerging Influenza Virus Infections during the Dominance of the Omicron SARS-CoV-2 Variant in Mexico.

The burden of influenza in Mexico has been high. We aimed to characterize its epidemiological patterns before and during the coronavirus disease 2019 (COVID-19) pandemic. A retrospective cohort study was conducted and 5652 PCR-confirmed cases of influenza (October 2019-April 2022) were analyzed. The highest incidence (144 per million) was observed in December 2019 and rapidly decreased right before the start of the pandemic (February 2020). No cases were documented in the 2020-2021 season, and infections reemerged at a low level (8 per million) in December 2021. The case-fatality rates were around 5% in both seasons (p = 0.591). The dominant strains were AH1N1 and AH3N2 in the 2019-2020 and 2021-2022 seasons, respectively. In multiple analysis, males and older patients were at increased risk of a fatal outcome. Flu vaccination and infection by B lineages (vs. AH1N1) showed a protective effect. Our results suggest that the spread of the influenza virus reemerged in the 2021-2022 season when the SARS-CoV-2 Omicron variant (B.1.1.529) was dominant. Efforts focusing on the prevention of transmission of respiratory viral pathogens, together with flu vaccination, may be useful to reduce the risk of an influenza outbreak.

COVID-19 Pneumonia in Fully Vaccinated Adults during the Dominance of the Omicron Sublineages BA.1.1 and BA.2 in Mexico.

Background and Objectives: A nationwide retrospective cohort study was conducted to evaluate the factors associated with the risk of laboratory-confirmed coronavirus disease 2019 (COVID-19)-related pneumonia in fully vaccinated adults during the dominance of the Omicron sublineages in Mexico. Materials and Methods: Fully COVID-19-vaccinated adults with laboratory-positive illness and symptom onset from April to mid-June 2022 were eligible. We computed the eta-squared (η2) to evaluate the effect size of the study sample. The characteristics predicting pneumonia were evaluated through risk ratios (RRs), and the 95% confidence intervals (CIs) were computed through generalized linear models. Results: The data from 35,561 participants were evaluated, and the overall risk of pneumonia was 0.5%. In multiple analyses, patients aged ≥ 60 years old were at increased risk of developing pneumonia (vs. 20-39 years old: RR = 1.031, 95% CI = 1.027-1.034). Chronic pulmonary obstructive disease, type 2 diabetes mellitus, arterial hypertension, chronic kidney disease (any stage), and immunosuppression (any cause) were also associated with a higher pneumonia risk. The η2 of all the variables included in the multiple models was <0.06. Conclusions: Our study suggests that, even when fully COVID-19-vaccinated, older adults and those with chronic conditions were at increased risk of pneumonia during the dominance of the Omicron sublineages BA.1.1 and BA.2.

Decreased survival in children inpatients with COVID-19 and antibiotic prescription.

BACKGROUND: The empirical prescription of antibiotics to inpatients with Coronavirus Disease 2019 (COVID-19) is frequent despite uncommon bacterial coinfections. Current knowledge of the effect of antibiotics on the survival of hospitalized children with COVID-19 is limited. OBJECTIVE: To characterize the survival experience of children with laboratory-positive COVID-19 in whom antibiotics were prescribed at hospital admission. METHODS: A retrospective cohort study was conducted in Mexico, with children hospitalized due to COVID-19 from March 2020 to December 2021. Data from 1601 patients were analyzed using the Kaplan-Meier method and the log-rank test. We computed hazard ratios (HR) and 95% confidence intervals (CI) to evaluate the effect of the analyzed exposures on disease outcomes. RESULTS: Antibiotics were prescribed to 13.2% ([Formula: see text] = 211) of enrolled children and a higher mortality rate [14.9 (95% CI 10.1-19.8) vs. 8.3 (95% CI 6.8-9.8)] per 1000 person-days, [Formula: see text] < 0.001) was found among them. At any given cut-off, survival functions were lower in antibiotic-positive inpatients ([Formula: see text] < 0.001). In the multiple model, antibiotic prescription was associated with a 50% increase in the risk of fatal outcome (HR = 1.50, 95% CI 1.01-2.22). A longer interval between illness onset and healthcare-seeking and pneumonia at hospital admission was associated with a poorer prognosis. CONCLUSIONS: Our results suggest that antibiotic prescription in children hospitalized due to COVID-19 is associated with decreased survival. If later replicated, these findings highlight the need for rational antibiotics in these patients.

Empirical Antibiotic Prescribing in Adult COVID-19 Inpatients over Two Years in Mexico.

Background and Objectives: Empirical antibiotic prescribing in patients with coronavirus disease 2019 (COVID-19) has been common even though bacterial coinfections are infrequent. The overuse of antibacterial agents may accelerate the antibiotic resistance crisis. We aimed to evaluate factors predicting empirical antibiotic prescribing to adult COVID-19 inpatients over 2 years (March 2020-February 2021) in Mexico. Materials and Methods: A cross-sectional analysis of a nationwide cohort study was conducted. Hospitalized adults due to laboratory-confirmed COVID-19 were included (n = 214,171). Odds ratios (OR) and 95% confidence intervals (CI), computed by using logistic regression models, were used to evaluate factors predicting empirical antibiotic prescribing. Results: The overall frequency of antibiotic usage was 25.3%. In multiple analysis, the highest risk of antibiotic prescription was documented among patients with pneumonia at hospital admission (OR = 2.20, 95% CI 2.16-2.25). Male patients, those with chronic comorbidities (namely obesity and chronic kidney disease) and longer interval days from symptoms onset to healthcare seeking, were also more likely to receive these drugs. We also documented that, per each elapsed week during the study period, the odds of receiving antibiotic therapy decreased by about 2% (OR = 0.98, 95% CI 0.97-0.99). Conclusion: Our study identified COVID-19 populations at increased risk of receiving empirical antibiotic therapy during the first two years of the pandemic.

Independent risk factors of COVID-19 pneumonia in vaccinated Mexican adults.

OBJECTIVES: To evaluate host factors associated with the risk of coronavirus disease 2019 (COVID-19) pneumonia in vaccinated adults. METHODS: A cohort study was conducted in Mexico, and data from 1607 adults with confirmed illness, with a positive history of COVID-19 vaccination, were analyzed. Risk ratios (RR) and 95% confidence intervals (CI) were computed as a measure of the significance of the associations between putative risk factors and the prevalence of COVID-19 pneumonia in vaccinated subjects. RESULTS: The overall risk of pneumonia was 1.98 per 1000 person-days. In the multiple regression analysis, older subjects, those with a history of smoking (current), obesity, and type 2 diabetes mellitus were at increased risk of pneumonia. CONCLUSIONS: Our results suggest that the effectiveness of COVID-19 vaccines may be reduced in a subset of adults who are older aged, smokers, obese, or have type 2 diabetes mellitus.

COVID-19 vaccines provide better protection against related pneumonia than previous symptomatic infection.

OBJECTIVES: To compare, in a real-world scenario, the protective effect of vaccination and previous laboratory-confirmed symptomatic infection on the risk of COVID-19 pneumonia. METHODS: A retrospective study was conducted and 46,998 adults with laboratory-confirmed COVID-19 were enrolled. Risk ratios (RRs) and 95% confidence intervals (CIs) were used to evaluate the effect of the evaluated exposures on the risk of pneumonia. RESULTS: In multiple analysis and after adjusting by reinfection status, vaccinated participants were at reduced risk of developing pneumonia (RR = 0.974, 95% CI 0.965-0.983). The association of having had a previous infection was not significant (RR = 1.001, 95% CI 0.969-1.034). CONCLUSION: Our results suggest, and if later replicated, that COVID-19 vaccines provide better protection against pneumonia than previous symptomatic infections. Therefore, offering vaccination to all eligible subjects despite past COVID-19 infections might be relevant to reducing the pandemic-related burden.

Survival in influenza virus-related pneumonia by viral subtype: 2016-2020.

BACKGROUND: Influenza remains a common cause of morbidity and mortality worldwide, and viral subtype-related differences in disease outcomes have been documented. OBJECTIVE: To characterize the survival experience of adult inpatients with influenza virus-associated pneumonia by viral subtype during five consecutive flu seasons. METHOD: We performed a retrospective cohort study; data from 4,678 adults were analyzed using the Kaplan-Meier method. A multivariate Cox proportional hazard regression model was fitted. RESULTS: The overall in-hospital mortality rate was 25.0 per 1,000 hospital days. The survival probabilities from pneumonia patients went from 93.4% (95% CI 92.6-94.1%) by day three to 43.3% (95% CI 39.2-47.4%) by day 30 from hospital admission. In general, the lowest survival rates were observed in patients with AH1N1 infection. In multiple models, after adjusting for comorbidities and when compared with A non-subtyped virus, pneumonia patients with AH3N2 or B strains had a significantly decreased risk of a non-favorable disease outcome. The association of other strains was not significant. CONCLUSIONS: Our findings suggest that the survival of inpatients with influenza virus-associated pneumonia varies according to the pathogenic viral subtype; the lowest survival rates were observed in patients with AH1N1 infection. This effect was independent of the patients' gender, age, and the analyzed underlying health conditions.

Symptomatic SARS-COV-2 reinfection: healthcare workers and immunosuppressed individuals at high risk.

BACKGROUND: Knowledge regarding factors predicting the SARS-COV-2 reinfection risk is scarce and it has major implications in public health policies. We aimed to identify factors associated with the risk of symptomatic SARS-COV-2 reinfection. METHODS: We conducted a nationwide retrospective cohort study and 99,993 confirmed cases of COVID-19 were analyzed. RESULTS: The overall risk of reinfection (28 or more elapsed days between both episodes onset) was 0.21% (incidence density, 2.5 reinfections per 100,000 person-days) and older subjects and those with the mild primary disease were at reduced risk of the event. Healthcare workers and immunosuppressed or renal patients had at greater risk of SARS-COV-2 reinfection. CONCLUSIONS: If replicated in other populations, these results may be useful to prioritize efforts focusing on the reduction of SARS-COV-2 spread and the related burden.

Performance of Antigen-Based Testing as Frontline Diagnosis of Symptomatic COVID-19.

Background and Objectives: To evaluate the performance of antigen-based detection tests as the frontline diagnosis of coronavirus disease 2019 (COVID-19). Materials and Methods: We conducted a nationwide retrospective cohort study in Mexico. A cross-sectional analysis of a cohort study was conducted in Mexico and data from 15,408 suspected (all of them symptomatic) cases of COVID-19 were analyzed. The results of antigen-based tests were compared with those obtained by molecular (polymerase chain reaction-based) assays. Results: The antigen-based tests showed sensitivity below 50% and high specificity in all the analyzed age groups. The highest Youden index (J) was observed among adults aged 25-44 years old (45.5, 95% CI 43.7-47.3). Conclusions: We documented the poor performance of serologic techniques as frontline diagnosis of symptomatic COVID-19 and inaccurate results may impact negatively on pandemic progression.

Effectiveness of BNT162b2 COVID-19 Vaccine in Preventing Severe Symptomatic Infection among Healthcare Workers.

Background and Objectives: This study aims to evaluate the effectiveness of the BNT162b2 COVID-19 (coronavirus disease 2019) in preventing severe symptomatic laboratory-confirmed infection among healthcare workers in a real-world scenario. Materials and Methods: A cross-sectional analysis of a prospective cohort study was conducted. Subjects with onset illness from January to February 2021 were eligible and classified according to the number of vaccine doses received (single-shot, n = 8; two-shot, n = 12; unvaccinated, n = 290). Results: The vaccine effectiveness against severe illness was 100% in the single and two-shot group. The presented results suggest that vaccination reduces the frequency of severe symptomatic COVID-19 in working-age adults. Conclusions: Efforts focusing on maximizing the number of immunized subjects in the study population may reduce associated economic and social burdens.

COVID-19 mortality among pregnant women in Mexico: A retrospective cohort study.

BACKGROUND: Pregnant women have been classified as at risk for COVID-19 due to previous experience with influenza and other coronaviruses. The objective of this study was to identify risk factors for the complications and death in women of childbearing age and pregnant women with suspected COVID-19. METHODS: This retrospective cohort study was conducted from the beginning of the epidemic in Mexico until May 25, 2020. All women of childbearing age (13-49 years) from the open national COVID-19 database from the Ministry of Health of Mexico were considered for eligibility. SARS-COV-2 infection was confirmed or ruled out by RT-qPCR. We performed a bivariate and multivariable analysis to estimate mortality risk. RESULTS: Ten (2.2%) pregnant women with confirmed COVID-19 died. Positive pregnant patients did not have a higher risk of complications (admission to the ICU, pneumonia, or requirement for mechanical ventilation) or death than the controls. In the multivariate analysis, only history of diabetes and chronic kidney disease remained independently associated with death in the positive cohort. Seven (0.6%) pregnant women with a negative test died. In bivariate analysis, pregnant patients with a positive test had a higher risk of death than pregnant patients with a negative test (relative risk (RR) = 3.87, 95% confidence interval (CI) = 1.48-10.12), but no higher risk was found than in non-pregnant women with a positive test (RR = 0.82, 95% CI = 0.44-1.53), and 60-day mortality did not significantly differ among pregnant patients with or without a positive test (hazard ratio (HR) = 0.40, 95% CI = 0.12-1.30) or between COVID-19-positive patients who were pregnant or not pregnant (HR = 0.74, 95% CI = 0.35-1.56). CONCLUSIONS: Pregnant patients do not have a greater risk of complications or death from COVID-19 than non-pregnant patients. The presence of diabetes mellitus and chronic disease increases the risk of death in women of childbearing age, but not specifically in pregnant patients.

Physical distancing reduced the incidence of influenza and supports a favorable impact on SARS-CoV-2 spread in Mexico.

INTRODUCTION: Physical distancing preventive measures were implemented in Mexico as a response to the coronavirus disease 2019 (CoViD-19) pandemic. School closures occurred on March 16, 2020, in 10 out of 32 Mexican states, and one week later in the remaining states. Because the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the influenza virus have similar transmission mechanisms, we aimed to evaluate the impact of physical distancing on the incidence of influenza as a proxy of the impact on SARS-CoV-2 contagion. METHODOLOGY: A national flu surveillance system was cross-sectionally analyzed and daily average percent changes (APCs) of incidence rates were calculated throught Poisson regression models. RESULTS: Greater decreasing trends (APCs -8.8, 95% CI: -12.5, -4.5; vs. -6.0, 95% CI: -9.9, -2.0; p = 0.026) were documented in the states with earlier school closures and across age groups, suggesting that earlier implementation of physical distance results in reduced SARS-CoV-2 spread. CONCLUSIONS: Physical distancing policies decrease the incidence of influenza infections in Mexico; its favorable impact on the spread of SARS-CoV-2 is commendable.

Male gender and kidney illness are associated with an increased risk of severe laboratory-confirmed coronavirus disease.

BACKGROUND: To identify factors predicting severe coronavirus disease 2019 (COVID-19) in adolescent and adult patients with laboratory-positive (quantitative reverse-transcription polymerase chain reaction) infection. METHOD: A retrospective cohort study took place, and data from 740 subjects, from all 32 states of Mexico, were analyzed. The association between the studied factors and severe (dyspnea requiring hospital admission) COVID-19 was evaluated through risk ratios (RRs) and 95% confidence intervals (CIs). RESULTS: Severe illness was documented in 28% of participants. In multiple analysis, male gender (RR = 1.13, 95% CI 1.06-1.20), advanced age ([reference: 15-29 years old] 30-44, RR = 1.02, 95% CI 0.94-1.11; 45-59, RR = 1.26, 95% CI 1.15-1.38; 60 years or older, RR = 1.44, 95% CI 1.29-1.60), chronic kidney disease (RR = 1.31, 95% CI 1.04-1.64) and thoracic pain (RR = 1.16, 95% CI 1.10-1.24) were associated with an increased risk of severe disease. CONCLUSIONS: To the best of our knowledge, this is the first study evaluating predictors of COVID-19 severity in a large subset of the Latin-American population. Male gender and kidney illness were independently associated with the risk of severe COVID-19. These results may be useful for health care protocols for the early detection and management of patients that may benefit from opportune and specialized supportive medical treatment.