## 3 Methodology
### Data Collection and Measurement
#### 3.1.2 Data Dictionary  
Table 1 describes the attributes used in this study.  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{3}{c}{Individual Record Form= Hospitalised Severe Acute Respiratory Syndrome Cases} \\ \hline
**Field Name** & **Type** & **Allowed Values** & **Description** \\ \hline FEVER & Varchar2 (1) & Did the patient have a fever? \\ \hline COUGH & Varchar2 (1) & Did the patient cough? \\ \hline DYSPNEA & Varchar2 (1) & Did the patient have dyspnea? \\ \hline THROAT & Varchar2 (1) & Did the patient have a sore throat? \\ \hline PAIN\_ABD & Varchar2 (1) & Did the patient have abdominal pain? \\ \hline FATIGUE & Varchar2 (1) & Did the patient experience fatigue? \\ \hline DIARRHEA & Varchar2 (1) & Did the patient have diarrhoea? \\ \hline SATURATION & Varchar2 (1) & Did the patient have O\({}_{2}\) saturation \textless{}95\%? \\ \hline VOMIT & Varchar2 (1) & Did the patient experience vomiting? \\ \hline PERD\_OLFT & Varchar2 (1) & Did the patient experience a loss of smell? \\ \hline LOST\_PALA & Varchar2 (1) & Did the patient experience taste loss? \\ \hline RISC\_FACTOR & Varchar2 (1) & Does the patient have risk factors? \\ \hline OBESITY & Varchar2 (1) & Does the patient have obesity? \\ \hline VACCINE & Varchar2 (1) & Was the patient vaccinated against influenza in the last campaign? \\ \hline \hline \end{tabular}
\end{table}
Table 1: Data dictionary.  
The data fields FEVER, COUGH, DYSPNEA, THROAT, PAIN_ABD, FATIGUE, DIARRHEA, SATURATION, VOMIT, PERD_OLFT (loss of smell), and LOST_PALA (loss of taste) store the respective signs and symptoms of the patient, according to codes 1--Yes (if) the patient presented the sign/symptom), 2--No (if the patient did not present the sign/symptom), or 0/9--Ignored (if the presence of the sign/symptom is unknown).  
In addition, the RISC_FACTOR data field records the patient's risk factors for worsening the disease. It is filled with codes 1--Yes or 2--No, depending on the existence or not of the risk factor, and 0/9--Ignored (if the presence of the risk factor is unknown). The BMI must be specified for the risk factor Obesity registered in the OBESITY field if code 1--Yes is marked for \"Obesity\".  
Information on the flu vaccine is registered in the VACCINE field. In this, data are obtained if the patient received the flu vaccine in the last flu vaccination campaign carried out in Brazil. It is filled in with the corresponding code, 1--Yes or 2--Patient's use of ventilatory support, which is recorded in the SUPPORT_VEN data field. It contains information on whether the patient used ventilatory support, with the corresponding code: 1--Yes, invasive (he used a ventilation technique with the patient with prostheses and endotracheal tubes that work as a patient/ventilatory support interface); 2--Yes, non-invasive (the patient used a ventilation technique in which a mask or similar device works as a patient/ventilatory support interface, without the use of prostheses and endotracheal tubes); and 3--No (the patient did not use ventilatory support).  
Finally, recording the evolution of the case, the EVOLUTION data field, where the corresponding code of the patient's clinical evolution is found: 1--Cure, 2--Death, and 3--Death by causes. See the clinical evolution of the case for the unknown code 9--Ignored is used.