This article summarizes what is currently known about the 2019 novel coronavirus and offers interim guidance.

Domestic travel creates a serious risk of spreading COVID-19, including novel strains of the virus. Motivating potential travelers to take precautions is critical, especially for those at higher risk for severe illness. To provide an evidence base for communication efforts, we examined the experiences and views of travelers during the summer of 2020 through a telephone survey of 1,968 US adults, conducted in English and Spanish, July 2 through July 16, 2020. The survey found that more than one-quarter (28%) of adults had traveled domestically in the prior 30 days, most commonly for "vacation" (43%), and less than half wore masks (46%) or practiced social distancing (47%) "all of the time." Although high-risk adults were significantly less likely to travel than non-high-risk adults (23% vs 31%; P < .001), they were no more likely to take precautions. Many travelers did not wear a mask or practice social distancing because they felt such actions were unnecessary (eg, they were outside or with friends and family). Although a substantial share of travelers (43% to 53%) trusted public health agencies "a great deal" for information about reducing risks while traveling, more travelers (73%) trusted their own healthcare providers. Findings suggest that outreach may be improved by partnering with providers to emphasize the benefits of layering precautions and provide targeted education to high-risk individuals. Messages that are empathetic to the need to reduce stress and convey how precautions can protect loved ones may be particularly resonant after more than a year of pandemic-related restrictions.

Public health travel restrictions (PHTR) are crucial measures during communicable disease outbreaks to prevent transmission during commercial airline travel and mitigate cross-border importation and spread. We evaluated PHTR implementation for US citizens on the Diamond Princess during its coronavirus disease (COVID-19) outbreak in Japan in February 2020 to explore how PHTR reduced importation of COVID-19 to the United States during the early phase of disease containment. Using PHTR required substantial collaboration among the US Centers for Disease Control and Prevention, other US government agencies, the cruise line, and public health authorities in Japan. Original US PHTR removal criteria were modified to reflect international testing protocols and enable removal of PHTR for persons who recovered from illness. The impact of PHTR on epidemic trajectory depends on the risk for transmission during travel and geographic spread of disease. Lessons learned from the Diamond Princess outbreak provide critical information for future PHTR use.

In January 2020, with support from the U.S. Department of Homeland Security (DHS), CDC instituted an enhanced entry risk assessment and management (screening) program for air passengers arriving from certain countries with widespread, sustained transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). The objectives of the screening program were to reduce the importation of COVID-19 cases into the United States and slow subsequent spread within states. Screening aimed to identify travelers with COVID-19-like illness or who had a known exposure to a person with COVID-19 and separate them from others. Screening also aimed to inform all screened travelers about self-monitoring and other recommendations to prevent disease spread and obtain their contact information to share with public health authorities in destination states. CDC delegated postarrival management of crew members to airline occupational health programs by issuing joint guidance with the Federal Aviation Administration.* During January 17-September 13, 2020, a total of 766,044 travelers were screened, 298 (0.04%) of whom met criteria for public health assessment; 35 (0.005%) were tested for SARS-CoV-2, and nine (0.001%) had a positive test result. CDC shared contact information with states for approximately 68% of screened travelers because of data collection challenges and some states' opting out of receiving data. The low case detection rate of this resource-intensive program highlighted the need for fundamental change in the U.S. border health strategy. Because SARS-CoV-2 infection and transmission can occur in the absence of symptoms and because the symptoms of COVID-19 are nonspecific, symptom-based screening programs are ineffective for case detection. Since the screening program ended on September 14, 2020, efforts to reduce COVID-19 importation have focused on enhancing communications with travelers to promote recommended preventive measures, reinforcing mechanisms to refer overtly ill travelers to CDC, and enhancing public health response capacity at ports of entry. More efficient collection of contact information for international air passengers before arrival and real-time transfer of data to U.S. health departments would facilitate timely postarrival public health management, including contact tracing, when indicated. Incorporating health attestations, predeparture and postarrival testing, and a period of limited movement after higher-risk travel, might reduce risk for transmission during travel and translocation of SARS-CoV-2 between geographic areas and help guide more individualized postarrival recommendations.