initial positive COVID-19 test results.
Of the primary cases, 89% developed mild or moderate symptoms, 11% were asymptomatic, and none had severe symptoms.
Household contacts of primary cases and people who were exposed to primary cases multiple times or for longer amounts of time had higher infection rates than other close contacts, the findings showed.
But all close contacts were more likely to be infected by the primary case if they were exposed shortly before or after that person developed symptoms, according to the study published online Aug. 23 in JAMA Internal Medicine.
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In comparison to mild and moderate symptomatic primary cases, those who were asymptomatic were much less likely to infect close contacts. If they did, the contacts were also less likely to have noticeable symptoms, the researchers report.
“Our results suggest that the timing of exposure relative to primary-case symptoms is important for transmission, and this understanding provides further evidence that rapid testing and quarantine after someone is feeling sick is a critical step to control the epidemic,” Martinez said. “This study further emphasizes the need for vaccination, which reduces clinical severity among people that develop COVID.”
If you believe you may have come in contact with COVID, you should get a rapid test as quickly as possible and self-isolate.