Mask Effectiveness for Preventing Secondary Cases of COVID-19, Johnson County, Iowa, USA

Details

• Alternative Title:
  Emerg Infect Dis
• Personal Author:
  Riley, Jacob ; Huntley, Jamie M. ; Miller, Jennifer A. ; Slaichert, Amelia L.B. ; Brown, Grant D.
• Description:
  In September of 2020, the Iowa Department of Public Health released guidance stating that persons exposed to someone with coronavirus disease (COVID-19) need not quarantine if the case-patient and the contact wore face masks at the time of exposure. This guidance differed from that issued by the Centers for Disease Control and Prevention. To determine the best action, we matched exposure information from COVID-19 case investigations with reported test results and calculated the secondary attack rates (SARs) after masked and unmasked exposures. Mask use by both parties reduced the SAR by half, from 25.6% to 12.5%. Longer exposure duration significantly increased SARs. Masks significantly reduced virus transmission when worn by both the case-patient and the contact, but SARs for each group were higher than anticipated. This finding suggests that quarantine after COVID-19 exposure is beneficial even if parties wore masks.
• Subjects:
  • Covid-19
  • Coronavirus Infections
  • Humans
  • Masks
  • Quarantine
  • Sars-Cov-2
• Source:
  Emerg Infect Dis. 2022; 28(1):69-75
• Pubmed ID:
  34637377
• Pubmed Central ID:
  PMC8714203
• Document Type:
  Journal Article
• Place as Subject:
  Iowa
• Volume:
  28
• Issue:
  1
• Download URL:
  https://stacks.cdc.gov/view/cdc/113338/cdc_113338_DS1.pdf
• File Type:
  [PDF - 1.16 MB]
• Collection(s):
  Emerging Infectious Diseases
• Main Document Checksum:
  urn:sha256:a75c42d46f103b97f1ac9e3a2fc6c7df02a6c05bb5dd2c233e7a150f0984d635