About 19 percent of people who were exposed to COVID-19 and remained negative or asymptomatic through the first week developed an infection by the end of the 14-day quarantine period, according to the CDC's Jan. 1 Morbidity and Mortality Weekly Report.
Using interim data from an ongoing study, CDC researchers identified 185 household contacts who were exposed to COVID-19. A total of 109 household contacts had detectable SARS-CoV-2 at any point during the 14-day quarantine period after exposure. Among the close contacts infected, 76 percent (83) of test results were positive within seven days after the index patient's illness onset, while 86 percent (94) of infections were detected within 10 days.
About 81 percent of household contacts who remained negative or asymptomatic through the first week after exposure did not develop COVID-19 through day 14. This increased to 93 percent for those who remained asymptomatic or negative through day 10.
In an effort to get more people to comply, the CDC trimmed its quarantine recommendations in December to 10 days without symptoms or seven days without symptoms and a negative test result.
In this latest report, researchers concluded the original 14-day quarantine period is the most effective way to minimize the spread of COVID-19.
"Although persons might be more adherent to a shorter quarantine period, such a policy is not without risk for further spread," the report said. "Persons released from quarantine before 14 days should continue to avoid close contact and wear masks when around others until 14 days after their last exposure."
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