At present, COVID-19 transmission has essentially been disrupted in China (4), and strengthening case surveillance and early detection of COVID-19 is the top priority of the current control and prevention strategies. The revised protocol clearly requires strengthening of case surveillance in medical institutions, communities, schools, etc., to further increase the sensitivity of case detection.
In medical institutions, Edition 7 expands the nucleic acid testing requirements. Patients with respiratory symptoms like fever and dry cough who have an epidemiological history should undergo nucleic acid testing. However, patients without an epidemiological history who have respiratory symptoms like fever and dry cough, have engaged in cold chain food processing or sales, or have been at a farmers market, institutions for the elderly or disabled, a hospital, a detention center, a nursing home, or a school should undergo nucleic acid testing for the COVID-19. In addition to the relatively recently-discovered transmission potential from contaminated frozen foods, many COVID-19 outbreaks have occurred in crowded and enclosed places, such as welfare institutions, places of detention, nursing homes, and schools. Therefore, routine nucleic acid testing of patients from these locations is conducive to early detection of COVID-19 and outbreak prevention.
For communities, management staff must monitor the health of key populations, including individuals discharged from hospitals or quarantine, close contacts of quarantined individuals, and people entering China who completed quarantine. Experience from the initial containment effort in China showed that 10% to 12% of patients with COVID-19 tested positive after discharge. Although transmission from positive-testing, discharged patients has not been observed in China, some people who entered China tested positive after being released from isolation. To ensure discovery of sources of infection as much as possible, Edition 7 requires health monitoring of people returning to communities from high-risk settings such as quarantine or a COVID-19 hospital.