Clinical characteristics and outcomes of influenza and other influenza-like illnesses in Mexico City

Abstract

Summary Background Influenza-like illnesses (ILI) are estimated to cause millions of deaths annually. Despite this disease burden, the etiologic causes of ILI are poorly described for many geographical regions. Methods Beginning in April 2010, we conducted an observational cohort study at five hospitals in Mexico City, enrolling subjects who met the criteria for ILI. Evaluations were conducted at enrollment and on day 28, with the collection of clinical data and a nasopharyngeal swab (or nasal aspirate in children). Swabs were tested by multiplex PCR for 15 viral pathogens and real-time PCR for influenza. Results During the first year, 1065 subjects were enrolled in this study, 55% of whom were hospitalized; 24% of all subjects were children. One or more pathogens were detected by PCR in 64% of subjects, most commonly rhinovirus (25% of all isolates) and influenza (24% of isolates). Six percent of subjects died, and of those, 54% had no pathogen identified. Rhinovirus was the most common pathogen among those who died, although it did not have the highest case fatality rate. Conclusions Multiple respiratory viruses beyond influenza are associated with significant morbidity and mortality among adults and children in Mexico City. Detection of these agents could be useful for the adjustment of antibiotic treatment in severe cases.

Respiratory viral infections among hospitalized adults: experience of a single tertiary healthcare hospital

“…The high proportion of non‐influenza infection in this study (72%) underscores the importance of non‐influenza viral infection in contributing to severe illness necessitating hospital and ICU admission in adults, as has been found by others . Rates of mortality were also similar to other studies; unfortunately, the number of fatal cases in our series was too small to allow for meaningful statistical comparison …”

“…Influenza infection is well recognized as the cause of significant healthcare costs, morbidity, and mortality in the United States; however, the role of non‐influenza respiratory viruses is not as well appreciated . The high proportion of non‐influenza infection in this study (72%) underscores the importance of non‐influenza viral infection in contributing to severe illness necessitating hospital and ICU admission in adults, as has been found by others . Rates of mortality were also similar to other studies; unfortunately, the number of fatal cases in our series was too small to allow for meaningful statistical comparison …”

Epidemiology and clinical characteristics of respiratory syncytial virus infections among children and adults in Mexico

“…The study (ILI‐002 Study) was carried out at five hospitals in Mexico City and one in San Luis Potosí. Results from patients enrolled during the first year of the study have previously been described . In this report, we analyzed the characteristics of 570 patients (399 children and 171 adults) with confirmed RSV infection included in the study during a 4‐year period.…”

“…The clinical presentation of this infection varies widely, from mild upper respiratory tract disease to bronchiolitis and pneumonia . This virus is responsible for the majority of bronchiolitis cases and causes approximately 50% of pneumonia cases during the first years of life . In children, host factors such as young age, prematurity, and chronic cardiopulmonary diseases have been associated with severe disease.…”

Is influenza-like illness a useful concept and an appropriate test of influenza vaccine effectiveness?

“…All ILI outpatients at five health centres in El Salvador, Honduras and Nicaragua 2006-2009 were tested by RT-PCR: Influenza A was identified in 7.4% of ILI cases, Influenza B 2.7%, RSV 6.9%, Adenoviruses 3.6%, Picornaviruses 3.2%, and Metapneumoviruses 0.2% [21]. In Mexico City in five hospitals in 2010 1065 ILI patients were tested by RT-PCR: 8% Influenza A, 6% Influenza B, 15.3% Rhinovirus, 7.3% Coronavirus, 5.4% RSV, 4% Metapneumovirus, 1.9% Parainfluenzavirus, and 11.9% mixed viral infections [22]. Three studies were in Asia.…”