Volume 26, Number 11—November 2020
Research Letter
Seroprevalence of SARS-CoV-2 and Infection Fatality Ratio, Orleans and Jefferson Parishes, Louisiana, USA, May 2020
, Daniel Fort, Julia Garcia-Diaz, Eboni G. Price-Haywood, Cruz Velasco, Eric Sapp, Dawn Pevey, and Leonardo Seoane
Table
Prevalence of SARS-CoV-2 infection and COVID-19–related IFR after 7 weeks of an active stay-at-home order, by race/ethnicity, 10 sites in Orleans and Jefferson Parishes, Louisiana, USA, May 9–15, 2020*
| Value | Total | White | Black | Asian | Native American | Pacific Islander | Multiracial or other | Hispanic† |
|---|---|---|---|---|---|---|---|---|
| Positive, no./total no. (%) |
183/2,640
(100) |
79/1,607
(60.9) |
90/828
(31.4) |
9/130
(4.9) |
0/14
(0.5) |
0/3
(0.1) |
5/58
(2.2) |
18/293
(11.1) |
| Orleans/Jefferson Parish residents, no. (%) |
825,057
(100) |
419,800
(50.8) |
356,925
(43.2) |
29,740
(3.6) |
4,088
(0.5) |
495
(0.1) |
14,009
(1.7) |
86,289
(10.5) |
| Unadjusted exposure‡ |
6.9
(6.0–8.0) |
4.9
(3.9–6.1) |
10.9
(8.8–13.2) |
6.9
(3.2–12.7) |
0 |
0 |
8.6
(2.9–19.0) |
6.1
(3.7–9.5) |
| Weighted exposure§ |
7.8
(7.8–7.9) |
5.9
(5.8–5.9) |
10.3
(10.2–10.4) |
6.4
(6.1–6.7) |
0 |
0 |
9.4
(9.0–10.0) |
7.5
(7.3– 7.7) |
| Weighted point prevalence¶ |
1.0
(0.6–1.3) |
1.3
(0.8–1.9) |
0.5
(0–1.0) |
0.9
(0–2.6) |
0 |
0 |
2.2
(0–5.9) |
2.2
(0.5–3.8) |
| Weighted seroprevalence# |
6.9
(6.8–6.9) |
4.5
(4.4–4.6) |
9.8
(9.7–9.9) |
5.5
(5.2–5.7) |
0 |
0 |
7.1
(6.7–7.6) |
5.3
(5.2–5.5) |
| No. presumed recovered** |
56,578 |
18,975 |
34,973 |
1,629 |
– |
– |
1,001 |
4,582 |
| No. deaths as of May 16, 2020 |
925 |
299 |
600 |
10 |
0 |
2 |
14 |
Unknown |
| IFR†† | 1.61 (1.5–1.7) | 1.55 (1.4–1.7) | 1.69 (1.6–1.8) | 0.61 (0.3–1.1)‡‡ | – | – | 1.38 (0.8–2.3) | – |
*Values are % (95% CI) except as indicated. The 2018 population estimates and deaths by race reported by the Louisiana Department of Public Health (4). Deaths are deemed to be COVID-19–related and have an associated confirmed PCR-positive test. Probable COVID-19 deaths without a positive PCR test were not included in these counts. By May 16, a total of 13,666 state-aggregated, confirmed cases had been reported in both parishes. COVID-19, coronavirus disease; IFR, infection fatality ratio; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; –, calculated value would be unreliable given low sample. †Hispanic ethnicity is a separate analysis and numbers were not subtracted from race. Hispanic deaths were not being reported as of May 16, 2020 (4). ‡Percentage of the sample with a PCR-positive test, an IgG-positive test, or both. §Census-weighted percentage of a PCR-positive test, an IgG-positive test, or both calculated to match 2018 racial demographics by parish and then combined. ¶Census-weighted percentage of PCR-positive and IgG-postive tests calculated to match 2018 racial demographics by parish and then combined. #Census-weighted percentage of IgG-positive tests calculated to match 2018 racial demographics by Parish and then combined. **Number of residents multiplied by weighted seroprevalence (IgG-positive tests). ††IFR equals the number of deaths per number of persons presumed recovered from SARS-CoV-2 infection plus deaths. ‡‡Significantly lower than White (p = 0.0034), Black (p = 0.0013), and multiracial or other (p = 0.0467) persons.