   <td>norovirus</td>
    </tr>
    <tr>
      <th>41</th>
      <td>frequency</td>
      <td>diagnostics</td>
      <td>respiratory syncytial virus</td>
      <td>hadv-3</td>
      <td>years old</td>
      <td>pulmonol</td>
      <td>positive</td>
      <td>pregnant</td>
      <td>des</td>
      <td>hazard ratio</td>
      <td>CHD</td>
      <td>h. influenzae</td>
      <td>niños</td>
      <td>low</td>
      <td>hcov nl63</td>
    </tr>
    <tr>
      <th>42</th>
      <td>virus</td>
      <td>1–4</td>