Study of the relationship between socio-demographic characteristics and new influenza A (H1N1)

Factors associated with death due to severe acute respiratory syndrome caused by influenza: Brazilian population study

Introduction

Influenza infection is characterized by acute viral infection of high transmissibility. Worsening of the case can lead to the need for hospitalization, severe acute respiratory syndrome (SARS) and even death.

Method

This is a cross-sectional population-based study that used secondary database from the Brazilian Influenza Epidemiological Surveillance Information System. Only cases of adults with diagnosis of influenza by RT-PCR and case evolution recorded were included.

Results

We identified 2,273 adults with SARS by influenza, 343 of which had death as an outcome. The main risk factors for death were lack of hospitalization, not having cough and age, both with p<0.001. In addition, without asthma, having black skin color, not receiving flu vaccine, having brown skin color and not having a sore throat (p≤ 0.005) were risk factors too.

Conclusion

Factors associated with death due to SARS caused by influenza in Brazil, risk factors and protective factors to death were identified. It was evident that those who did not receive the flu vaccine presented twice the risk of unfavorable outcome, reinforcing the need to stimulate adherence to vaccination adhering and propose changes in public policies to make influenza vaccines available to the entire population, in order to prevent severe cases and unfavorable outcomes.

The Effect of Social Distancing on the Early Spread of the Novel Coronavirus

This article quantifies the effect of individual social distancing on the spread of the novel coronavirus. To do so, we use data on time spent by individuals on activities that would potentially expose them to crowds from the American Time Use Survey linked with state-level data on positive tests from the COVID Tracking Project. We estimate count data specifications of observed COVID-19 infections at the state level as a function of control demographic variables, and a measure of social distance that captures the amount of time individuals across the states spend in activities that potentially expose them to crowds. Parameter estimates reveal that the number of state-level novel coronavirus infections decrease with respect to our measure of individual social distance. From a practical perspective, our parameter estimates suggest that if the typical individual in a U.S. state were to spend eight hours away from crowds completely, this would translate into approximately 240,000 fewer COVID-19 infections across the states. Our results suggest that, at least in the United States, social distancing policies are effective in slowing the spread of the novel coronavirus.

A DESCRIPTIVE STUDY OF PANDEMIC INFLUENZA A(H1N1)PDM09 IN BRAZIL, 2009 - 2010

Influenza A viruses undergo frequent antigenic mutations and may thus cause seasonal epidemics and pandemics. The aim of this study was to recover the epidemiological history of the pandemic influenza A(H1N1)pdm09 in Brazil. A descriptive study was conducted in 2009-2010. The Brazilian Information System for reportable diseases (SINAN) was the data source. A total of 105,054 suspected cases of influenza A(H1N1)pdm09 were reported to SINAN. Of these, 53,797 (51.2%) were classified as the new influenza virus subtype. Among the confirmed cases, 56.7% were female, the mean age was 26.31 (SD ± 18.1) years. Fever was the most common sign among the confirmed cases (99.7%) and the presence of comorbidities was reported in 32.5% of cases. In 2009 there were confirmed cases in all 26 Brazilian States and the Federal District. The incidence (per 100,000 inhabitants) of severe influenza in the population was 28.0 in 2009 and 0.5 in 2010. The states of Paraná (301.3), Santa Catarina (36.0) and Rio Grande do Sul (27.4) presented the highest incidence; 46.4% of the confirmed cases were hospitalized and 47,643 were cured (93.8%). The case-fatality rate was 3.9% in 2009. The pandemic virus A(H1N1)pdm09 hit Brazil between April/2009 and December/2010 with an important difference in the geographic pattern distribution of the cases from the northeast to the south of the country. Children and young adults were the most affected. The limitations of the study were data quality and inconsistencies in the final classification of cases in SINAN. This study highlights the urgent need for improvements in the surveillance of emerging diseases in Brazil.

Clinical aspects of influenza A(H1N1)pdm09 cases reported during the pandemic in Brazil, 2009-2010

OBJECTIVE

To describe the clinical aspects of cases of influenza A(H1N1)pdm09 in Brazil.

METHODS

A descriptive study of cases reported in Sistema de Informação de Agravos de Notificação (SINAN), 2009-2010.

RESULTS

As the final classification, we obtained 53,797 (56.79%) reported cases confirmed as a new influenza virus subtype, and 40,926 (43.21%) cases discarded. Fever was the most common sign, recorded in 99.74% of the confirmed and 98.92% of the discarded cases. Among the confirmed cases, the presence of comorbidities was reported in 32.53%, and in 38.29% of the discarded cases. The case fatality rate was 4.04%; 3,267 pregnant women were confirmed positive for influenza A new viral subtype and 2,730 of them were cured. The case fatality rate of pregnant women was 6.88%.

CONCLUSION

The findings suggested concern of the health system with pregnant women, and patients with comorbidities and quality of care may have favored a lower mortality. We recommend that, when caring for patients with severe respiratory symptoms, with comorbidities, or pregnant women, health professionals should consider the need for hospital care, as these factors make up a worse prognosis of infection by the pandemic influenza virus.