TABLE. Weekly emergency department (ED) sentinel surveillance results and SARS-CoV-2 prevalence estimations among persons with influenza-like symptoms (ILS) of all ages and those <18 years of age — New York City (NYC), March 2020.
| Characteristic | Age group |
|||
|---|---|---|---|---|
| All ages |
<18 yrs |
|||
| Wk beginning Mar 1 | Wk beginning Mar 8 | Wk beginning Mar 8 | Wk beginning Mar 15 | |
| ED visits for ILS citywide,* no. |
17,137 |
24,511 |
7,546 |
4,464 |
| ED visits for ILS at sentinel sites, no. |
1,145 |
3,019 |
479 |
778 |
| ED visits for ILS at sentinel sites with influenza tests performed, no. (%)† |
449 (39.2) |
1,606 (53.2) |
440 (91.9) |
252 (32.4) |
| ED visits for ILS at sentinel sites with negative influenza test results, no. (%) |
336 (74.8) |
1,275 (79.4) |
328 (74.5) |
224 (88.9) |
| Target population, no. of persons§ |
5,029 |
10,352 |
5,167 |
1,285 |
| Sentinel surveillance specimens collected, no. |
244 |
181 |
37 |
82 |
| Specimens positive for SARS-CoV-2, no. (%) |
3 (1.2) |
19 (10.5) |
1 (2.7) |
13 (15.9) |
| Estimated SARS-CoV-2 prevalence in target population,¶ % (CL)** |
0.3 (0.0–3.5) |
11.3 (6.2–20.0) |
2.0 (0.0–17.3) |
17.7 (9.1–32.8) |
| Estimated undetected COVID-19 cases in target population, no. (CL)†† |
15 (0–176) |
1,170 (642–2,070) |
103 (0–894) |
227 (117–422) |
| Confirmed COVID-19 cases in NYC,§§ no. | 26 | 1,917 | 42 | 457 |
Abbreviations: CL = confidence limit; COVID-19 = coronavirus disease 2019; Wk = week.
* ILS are defined as having at least one of the following signs or symptoms recorded in the ED chief complaint: chills, fever, upper respiratory infection, cough, sore throat, runny nose, congestion, headache, or fatigue.
† Limited to sentinel EDs that contributed samples during the specified week.
§ Target population is defined as those persons evaluated at any NYC ED with ILS who had negative test results for influenza (and, in some instances, for other respiratory pathogens). The target population is calculated using the following formula: ED visits for ILS citywide x (ED visits for ILS at sentinel sites with influenza tests performed/ED visits for ILS at sentinel sites) x (ED visits for ILS at sentinel sites with negative influenza test results/ED visits for ILS at sentinel sites with influenza tests performed).
¶ Point estimate calculated using estimated true prevalence tool (https://epitools.ausvet.com.au/trueprevalence), assuming 85% sensitivity and 99% specificity for the SARS-CoV-2 reverse transcription–polymerase chain reaction (RT-PCR) test for nasopharyngeal samples collected from symptomatic patients.
** Lower confidence limit calculated assuming 95% test sensitivity. Upper confidence limit calculated assuming 75% test sensitivity. All calculations assume 99% test specificity.
†† Calculated by multiplying target population by estimated prevalence and by lower and upper confidence limits.
§§ Confirmed cases are defined as having first positive SARS-CoV-2 RT-PCR test result reported to the NYC Department of Health and Mental Hygiene among NYC residents, as of June 18, 2020, with the specimen collected during the week specified.