Details:

Personal Author:
Oster, Alexandra M. ; Caruso, Elise ; DeVies, Jourdan ; Hartnett, Kathleen P. ; Boehmer, Tegan K.
Oster, Alexandra M. ; Caruso, Elise ; DeVies, Jourdan ; Hartnett, Kathleen P. ; Boehmer, Tegan K. Less -
Corporate Authors:
CDC COVID-9 Response Team.
Description:
CDC works with other federal agencies to identify counties with increasing coronaVirus disease 2019 (COVID-19) incidence (hotspots) and offers support to state, tribal, local, and territorial health departments to limit the spread of SARS-CoV-2, the Virus that causes COVID-19 (1). Understanding whether increasing incidence in hotspot counties is predominantly occurring in specific age groups is important for identifying opportunities to prevent or reduce Transmission. The percentage of positive SARS-CoV-2 reverse transcription–polymerase chain reaction (RT-PCR) test results (percent positivity) is an important indicator of community Transmission.* CDC analyzed temporal Trends in percent positivity by age group in COVID-19 hotspot counties before and after their identification as hotspots. Among 767 hotspot counties identified during June and July 2020, early increases in the percent positivity among persons aged ≤24 years were followed by several weeks of increasing percent positivity in persons aged ≥25 years. Addressing Transmission among young adults is an urgent public health priority.

Hotspot counties were identified by applying previously described standardized criteria to detect counties that had >100 cases during the past 7 days and experienced increases in cases in the preceding 3–7 days (1). Counties identified as hotspots during June 1–July 31, 2020, that had not met hotspot criteria in the previous 21 days were included. SARS-CoV-2 RT-PCR test results were obtained from data submitted by state health departments and laboratories.† Percent positivity was calculated by dividing the number of positive test results by the sum of positive and negative test results for each age group (0–17, 18–24, 25–44, 45–64, and ≥65 years) for the 45 days before and 45 days after hotspot detection (spanning April–September 2020) based on specimen collection or test order date. Data were presented using a 7-day moving average. Results were aggregated across all hotspot counties and stratified by age group. Analyses were conducted using R software (version 3.6.0; The R Foundation).

The 767 hotspot counties detected during June 1–July 31 represented 24% of all U.S. counties and 63% of the U.S. population. Percent positivity among persons aged 0–17 and 18–24 years began increasing 31 days before hotspot identification. Increases in percent positivity among older age groups began after the increases in younger age groups: among adults aged 25–44 years, 45–64 years, and ≥65 years, increases began 28 days, 23 days, and 20 days, respectively, before hotspot identification (Figure 1). At the time of hotspot detection, the highest percent positivity was among persons aged 18–24 years (14%), followed by those aged 0–17 years (11%), 25–44 years (10%), 45–64 years (8%), and ≥65 years (6%). Percent positivity among persons aged 18–24 years was near its peak of 15% by the date of hotspot detection; however, among other age groups, percent positivity continued to increase for 21–33 days after hotspot detection, peaking at 10%–14%, and the decline for other age groups was slower than that for persons aged 18–24 years.

Suggested citation for this article: Oster AM, Caruso E, DeVies J, Hartnett KP, Boehmer TK. Transmission Dynamics by Age Group in COVID-19 Hotspot Counties — United States, April–September 2020. MMWR Morb Mortal Wkly Rep. ePub: 9 October 2020.

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Subjects:
[+]
Age Groups CoronaVirus Infections COVID-19 Incidence Pandemics Pneumonia, Viral
Series:
MMWR. Morbidity and Mortality Weekly Report ; v. 69, early release, October 9, 2020
Document Type:
Journal Article
Place as Subject:
United States
Collection(s):
Morbidity and Mortality Weekly Report (MMWR)
Main Document Checksum:
[+]
urn:sha256:6f9019baccb205bd8bb2fe0c033d0bab7038761d9c1d4a499035ac77d46ec640
Download URL:
https://stacks.cdc.gov/view/cdc/95128/cdc_95128_DS1.pdf
File Type:

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