Contact Tracing Assessment of #COVID-19 #Transmission Dynamics in Taiwan and Risk at Different Exposure Periods Before and After Symptom Onset | Global Health | JAMA Internal Medicine | JAMA Network
▻https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2765641
Suivi de 2761 sujets contacts (que le contact ait eu lieu- jusqu’à 4 jours- avant ou après le développement des symptômes) de 100 sujets PCR SARS-CoV2 positifs dont 9 qui sont restés asymptomatiques. Pour ces derniers c’est la date de confirmation qui a été prise en compte pour détecter les contacts.
Les contacts très étroits ont été systématiquement testés tandis que les autres contacts n’ont été testés qu’en cas d’apparition de symptômes.
The overall secondary clinical attack rate was 0.7% (95% CI, 0.4%-1.0%). The attack rate was higher among the 1818 contacts whose exposure to index cases started within 5 days of symptom onset (1.0% [95% CI, 0.6%-1.6%]) compared with those who were exposed later ( 0 cases from 852 contacts ; 95% CI, 0%-0.4%). The 299 contacts with exclusive presymptomatic exposures were also at risk (attack rate, 0.7% [95% CI, 0.2%-2.4%]). The attack rate was higher among household (4.6% [95% CI, 2.3%-9.3%]) and nonhousehold (5.3% [95% CI, 2.1%-12.8%]) family contacts than that in health care or other settings. The attack rates were higher among those aged 40 to 59 years (1.1% [95% CI, 0.6%-2.1%]) and those aged 60 years and older (0.9% [95% CI, 0.3%-2.6%]).
Aucun des 91 contacts des cas asymptomatiques n’a développé de symptômes.