Epidemiological study of influenza type A complications in pediatric patients

¶ … Epidemiological Study on Influenza

Malaria

The study hypothesized that in a population with high risk of developing complications, there is bound to be a high incidence of severe cases and lethality of type A influenza (Lera et al., 2011, p. 372).

The study population is the children attended to at the University Hospital Vall d'Hebron which is a third-level center in Barcelona. The facility serves a population of 45,000 and attends to patients up to the age of 16 years. The study included all patients seen at the pediatric emergency room between July 1st and December 31st of 2009 who were suffering from clinically suspected influenza type A (H1N1). The patients had to meet the criteria for microbiological study according to the Departament de Salut of the Generalitat de Catalunya protocol. The patients had to have travelled to an epidemic region or come into contact with a confirmed case in the last 10 days before the onset of their symptoms. The patients were given empirical treatment with oseltamivir except for those below 1 year of age. If the microbiological study proved negative, treatment was also stopped. Patients who had confirmed cases of influenza type A were followed by through the use of telephone interviews to collect data on the clinical manifestation, duration, and any adverse effects as a result of the antiviral treatment administered (Lera et al., 2011, p. 372).

Risk factors or exposures being studied

The variables that were being studied were age, sex, co-morbidity with diseases such as chronic lung disease, diabetes mellitus, cardiovascular disease, chronic liver disease, immunosuppression, asplenia or chronic treatment with acetylsalicyclic acid, neuromuscular disease or encephalopathy, and haemoglobinopathy or underlying blood disorders, pneumonia on admission, prescription of antiviral treatment and the time that elapsed since the onset of the symptoms, close contact with subjects that are high-risk, clinical symptoms at the time of diagnosis, hospital admission and evolution (Lera et al., 2011, p. 372).

Health outcome being studied and measurement of health outcome variable

The health outcome being studied is the incidence of severe cases of type A influenza and the lethality of infection in a population which is at risk of developing complications. This health outcome was measured by following up with all confirmed cases of type A influenza virus in order to collect data on the clinical manifestation, duration, and any adverse effects as a result of the antiviral treatment administered (Lera et al., 2011, p. 372).

Statistical methods of analysis

Types of procedures used, estimates of risk used and statistical software used

A descriptive analysis was conducted on the epidemiological, demographic and clinical variables collected. Patients were compared in accordance with their need for admission in order to detect variables which are associated with the impending risk of hospitalization. Mann-Whitney's U test was used to conduct statistical analysis for the continuous variables while contingency tables were used for the categorical variables. Chi-square tests were also calculated while odds ratio and a confidence interval of 95% was estimated. To study the factors that are independently associated with the admission probability, a multiple regression analysis was conducted. Version 15.0 of the Statistical Package for the Social Sciences (SPSS) was used to perform statistical analysis with a p value of

Limitations of the study and possible sources of bias

The series in the study only describe patients who were hospitalized in the emergency room and not all children treated in the hospital who had type A influenza. Furthermore, any patients who were directly referred from other centers or other outpatient areas were not included in the study. The cases studied represented only 5.57% of the total number of cases seen at the center. One potential source of bias was the inclusion of patients who were aged 17 to 21 years. This group of patients was less than 1% of the total population which led the researcher to feel that they did not introduce bias to the study (Lera et al., 2011, p. 377).

Results of the study

The median age for patients infected with type A influenza was 7 years which was consistent with the data from the center and other countries round the world. 20.6% of the confirmed cases required admission with only 3 patients being admitted at the PICU center and 2 patients (0.5%) dying. Patients who required admission were significantly younger than those who did not. 82% of confirmed cases of influenza type A and 67% of the admitted patients presented the risk factors being studied. Patients who were admitted had fewer risk factors than those who were not admitted. This can be attributed to the age of the patients. It was found that antiviral treatment helps to reduce the duration of symptoms. The study also established the safety of oseltamivir for children since only 8.7% of patients had mild effects mainly gastrointestinal (Lera et al., 2011, pp. 374-377).

Practical implications of results of the study

The results show that influenza type A has high morbidity with low incidence of severe cases and low lethality. The study ascertained the safety of oseltamivir as a diagnostic or therapeutic strategy for influenza type A virus.