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BackgroundThe natural history of SARS-CoV-2 infection and transmission dynamics may have changed as SARS-CoV-2 has evolved and population immunity has shifted.MethodsHousehold contacts, enrolled from two multi-site case-ascertained household transmission studies (April 2020–April 2021 and September 2021–September 2022), were followed for 10–14 days after enrollment with daily collection of nasal swabs and/or saliva for SARS-CoV-2 testing and symptom diaries. SARS-CoV-2 virus lineage was determined by whole genome sequencing, with multiple imputation where sequences could not be recovered. Adjusted infection risks were estimated using modified Poisson regression.Findings858 primary cases with 1473 household contacts were examined. Among unvaccinated household contacts, the infection risk adjusted for presence of prior infection and age was 58% (95% confidence interval [CI]: 49–68%) in households currently exposed to pre-Delta lineages and 90% (95% CI: 74–100%) among those exposed to Omicron BA.5 (detected May – September 2022). The fraction of infected household contacts reporting any symptom was similarly high between pre-Delta (86%, 95% CI: 81–91%) and Omicron lineages (77%, 70–85%). Among Omicron BA.5-infected contacts, 48% (41–56%) reported fever, 63% (56–71%) cough, 22% (17–28%) shortness of breath, and 20% (15–27%) loss of/change in taste/smell.InterpretationThe risk of infection among household contacts exposed to SARS-CoV-2 is high and increasing with more recent SARS-CoV-2 lineages. This high infection risk highlights the importance of vaccination to prevent severe disease.FundingFunded by the Centers for Disease Control and Prevention and the Food and Drug Administration.Key points-Monitoring the transmissibility and symptomatology of SARS-CoV-2 lineages is important for informing public health practice and understanding the epidemiology of COVID-19; household transmission studies contribute to our understanding of the natural history of SARS-CoV-2 infections and the transmissibility of SARS-CoV-2 variants.-The Omicron BA.5 sub-lineage is highly transmissible, similar to previous Omicron sub-lineages.-Over 80% of infected household contacts reported at least 1 symptom during their infection and the proportion of household contacts with asymptomatic infection did not differ by SARS-CoV-2 variant. The most common symptom was cough. Change in taste or smell was more common in Omicron BA.5 infections, compared to previous Omicron sub-lineages, but less common compared to pre-Delta lineages.-The high infection risk among household contacts supports the recommendations that individuals maintain up-to-date and lineage-specific vaccinations to mitigate further risks of severe disease.

During November 19-21, 2021, an indoor convention (event) in New York City (NYC), was attended by approximately 53,000 persons from 52 U.S. jurisdictions and 30 foreign countries. In-person registration for the event began on November 18, 2021. The venue was equipped with high efficiency particulate air (HEPA) filtration, and attendees were required to wear a mask indoors and have documented receipt of at least 1 dose of a COVID-19 vaccine.* On December 2, 2021, the Minnesota Department of Health reported the first case of community-acquired COVID-19 in the United States caused by the SARS-CoV-2 B.1.1.529 (Omicron) variant in a person who had attended the event (1). CDC collaborated with state and local health departments to assess event-associated COVID-19 cases and potential exposures among U.S.-based attendees using data from COVID-19 surveillance systems and an anonymous online attendee survey. Among 34,541 attendees with available contact information, surveillance data identified test results for 4,560, including 119 (2.6%) persons from 16 jurisdictions with positive SARS-CoV-2 test results. Most (4,041 [95.2%]), survey respondents reported always wearing a mask while indoors at the event. Compared with test-negative respondents, test-positive respondents were more likely to report attending bars, karaoke, or nightclubs, and eating or drinking indoors near others for at least 15 minutes. Among 4,560 attendees who received testing, evidence of widespread transmission during the event was not identified. Genomic sequencing of 20 specimens identified the SARS-CoV-2 B.1.617.2 (Delta) variant (AY.25 and AY.103 sublineages) in 15 (75%) cases, and the Omicron variant (BA.1 sublineage) in five (25%) cases. These findings reinforce the importance of implementing multiple, simultaneous prevention measures, such as ensuring up-to-date vaccination, mask use, physical distancing, and improved ventilation in limiting SARS-CoV-2 transmission, during large, indoor events.

On December 2, 2021, the Minnesota Department of Health (MDH) notified CDC of a COVID-19 case caused by sequence-confirmed SARS-CoV-2 B.1.1.529 (Omicron) variant in a Minnesota resident (patient A), the first such case identified in the state and one of the earliest identified in the United States. Patient A had attended a large indoor convention in New York, New York with approximately 53,000 attendees from 52 U.S jurisdictions and 30 foreign countries during November 19-21, 2021, and had close contact

We aimed to describe frequency of COVID-19 exposure risk factors among patients presenting for medical care at an urban, public hospital serving mostly uninsured/Medicare/Medicaid clients and risk factors associated with SARS-CoV-2 infection. Consenting, adult patients seeking care at a public hospital from August to November 2020 were enrolled in this cross-sectional investigation. Saliva, anterior nasal and nasopharyngeal swabs were collected and tested for SARS-CoV-2 using RT-PCR. Participant demographics, close contact, and activities ≤14 days prior to enrollment were collected through interview. Logistic regression was used to identify risk factors associated with testing positive for SARS-CoV-2. Among 1,078 participants, 51.8% were male, 57.0% were aged ≥50 years, 81.3% were non-Hispanic Black, and 7.6% had positive SARS-CoV-2 tests. Only 2.7% reported COVID-19 close contact ≤14 days before enrollment; this group had 6.79 adjusted odds of testing positive (95%CI = 2.78–16.62) than those without a reported exposure. Among participants who did not report COVID-19 close contact, working in proximity to ≥10 people (adjusted OR = 2.17; 95%CI = 1.03–4.55), choir practice (adjusted OR = 11.85; 95%CI = 1.44–97.91), traveling on a plane (adjusted OR = 5.78; 95%CI = 1.70–19.68), and not participating in an essential indoor activity (i.e., grocery shopping, public transit use, or visiting a healthcare facility; adjusted OR = 2.15; 95%CI = 1.07–4.30) were associated with increased odds of testing positive. Among this population of mostly Black, non-Hispanic participants seeking care at a public hospital, we found several activities associated with testing positive for SARS-CoV-2 infection in addition to close contact with a case. Understanding high-risk activities for SARS-CoV-2 infection among different communities is important for issuing awareness and prevention strategies.

Nasopharyngeal swabs (NPS) collected by trained healthcare professionals are the preferred specimen for SARS-CoV-2 testing. Self-collected specimens might decrease patient discomfort, conserve healthcare resources, and be preferred by patients. During August – November 2020, 1,806 adults undergoing SARS-CoV-2 testing in Denver, Colorado and Atlanta, Georgia, provided self-collected anterior nares swabs (ANS) and saliva specimens before NPS collection. Compared to NPS, sensitivity for SARS-CoV-2 detection by rRT-PCR appeared higher for saliva than for ANS (85% versus 80% in Denver; 67% versus 58% in Atlanta) and higher among participants reporting current symptoms (94% and 87% in Denver; 72% and 62% in Atlanta, for saliva and ANS, respectively) than among those reporting no symptoms (29% and 50% in Denver; 50% and 44% in Atlanta, for saliva and ANS, respectively). Compared to ANS, saliva was more challenging to collect and process. Self-collected saliva and ANS are less sensitive than NPS for SARS-CoV-2 detection; however, they offer practical advantages and might be most useful for currently symptomatic patients.

(1) Background: The reliability of disease surveillance may be restricted by sensitivity or ability to capture all disease. Objective: To quantify under-reporting and concordance of recording persons with tuberculosis (TB) in national TB surveillance systems: the Infectious Disease Reporting System (IDRS) and Tuberculosis Information Management System (TBIMS). (2) Methods: This retrospective review includes 4698 patients identified in 2016 in China. County staff linked TB patients identified from facility-specific health and laboratory information systems with records in IDRS and TBIMS. Under-reporting was calculated, and timeliness, concordance, accuracy, and completeness were analyzed. Multivariable logistic regression was used to examine factors associated with under-reporting. (3) Results: We found that 505 (10.7%) patients were missing within IDRS and 1451 (30.9%) patients were missing within TBIMS. Of 171 patient records reviewed in IDRS and 170 patient records in TBIMS, 12.3% and 6.5% were found to be untimely, and 10.7% and 7.1% were found to have an inconsistent home address. The risk of under-reporting to both IDRS and TBIMS was greatest at tertiary health facilities and among non-residents, the risk of under-reporting to TBIMS was greatest with patients aged 65 or older and with extrapulmonary TB (EPTB). (4) Conclusions: It is important to improve the reporting and recording of TB patients. Local TB programs that focus on training, and mentoring high-burden hospitals, facilities that cater to EPTB, and migrant patients may improve reporting and recording.

Background: The reliability of disease surveillance may be restricted by sensitivity or the ability of the system to capture all disease. Our objective was to quantify under-reporting and concordance of recording persons with tuberculosis (TB) in the national TB surveillance systems: Infectious Disease Reporting System (IDRS) and TB Information Management System (TBIMS). Methods: This retrospective review includes patients identified in 2016 from six counties in Guangdong, Jiangsu, Henan, Heilongjiang, Sichuan, and Yunnan provinces. County staff linked TB patients identified from facility-specific health and laboratory information systems with TB patients recorded in IDRS and TBIMS. Under-reporting was calculated as the percentage of TB patients not recorded in IDRS or TBIMS. Timeliness, patients recorded within 24 hours after diagnosis, and concordance, accuracy and completeness of key variables when compared to medical records, were analyzed through comparing sampled patient-records with corresponding patient-records in health facilities. Multivariable logistic regression was used to examine factors associated with under-reporting. Results: We found 505 (10.7%) patients diagnosed with TB were missing within IDRS and 1451 (30.9%) patients were missing within TBIMS. Of 171 patient-records reviewed in IDRS and 170 patient-records in TBIMS, 12.3% and 6.5% were found to be untimely, 10.7% and 7.1% were found having inconsistent home address. The risk of under-reporting to both IDRS and TBIMS was greatest in TB diagnosis at a tertiary health facilities and non-residents; the risk of under-reporting to TBIMS was greatest with patients aged 65 or older and extrapulmonary TB (EPTB).Conclusions: We found that more than one in four TB patients were not recorded in TBIMS. It is important to improve the reporting and recording of TB patients. Local TB programs that focus on training, and mentoring high-burden hospitals, facilities that cater to EPTB, and migrant patients may improve reporting and recording. Additional human resources for data collection and management, and monitoring and evaluation systems are needed to improve national surveillance systems and TB prevention, diagnosis and treatment services.

Background Coronavirus disease 2019 (COVID-19) is a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first detected in China in December, 2019. In January, 2020, state, local, and federal public health agencies investigated the first case of COVID-19 in Illinois, USA. Methods Patients with confirmed COVID-19 were defined as those with a positive SARS-CoV-2 test. Contacts were people with exposure to a patient with COVID-19 on or after the patient's symptom onset date. Contacts underwent active symptom monitoring for 14 days following their last exposure. Contacts who developed fever, cough, or shortness of breath became persons under investigation and were tested for SARS-CoV-2. A convenience sample of 32 asymptomatic health-care personnel contacts were also tested. Findings Patient 1-a woman in her 60s-returned from China in mid-January, 2020. One week later, she was hospitalised with pneumonia and tested positive for SARS-CoV-2. Her husband (Patient 2) did not travel but had frequent close contact with his wife. He was admitted 8 days later and tested positive for SARS-CoV-2. Overall, 372 contacts of both cases were identified; 347 underwent active symptom monitoring, including 152 community contacts and 195 health-care personnel. Of monitored contacts, 43 became persons under investigation, in addition to Patient 2. These 43 persons under investigation and all 32 asymptomatic health-care personnel tested negative for SARS-CoV-2. Interpretation Person-to-person transmission of SARS-CoV-2 occurred between two people with prolonged, unprotected exposure while Patient 1 was symptomatic. Despite active symptom monitoring and testing of symptomatic and some asymptomatic contacts, no further transmission was detected. Funding None.

Coronavirus disease 2019 (COVID-19), the respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and has since become pandemic. In response to the first cases identified in the United States, close contacts of confirmed COVID-19 cases were investigated to enable early identification and isolation of additional cases and to learn more about risk factors for transmission. Close contacts of nine early travel-related cases in the United States were identified and monitored daily for development of symptoms (active monitoring). Selected close contacts (including those with exposures categorized as higher risk) were targeted for collection of additional exposure information and respiratory samples. Respiratory samples were tested for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction at the Centers for Disease Control and Prevention. Four hundred four close contacts were actively monitored in the jurisdictions that managed the travel-related cases. Three hundred thirty-eight of the 404 close contacts provided at least basic exposure information, of whom 159 close contacts had ≥1 set of respiratory samples collected and tested. Across all actively monitored close contacts, two additional symptomatic COVID-19 cases (i.e., secondary cases) were identified; both secondary cases were in spouses of travel-associated case patients. When considering only household members, all of whom had ≥1 respiratory sample tested for SARS-CoV-2, the secondary attack rate (i.e., the number of secondary cases as a proportion of total close contacts) was 13% (95% CI: 4-38%). The results from these contact tracing investigations suggest that household members, especially significant others, of COVID-19 cases are at highest risk of becoming infected. The importance of personal protective equipment for healthcare workers is also underlined. Isolation of persons with COVID-19, in combination with quarantine of exposed close contacts and practice of everyday preventive behaviors, is important to mitigate spread of COVID-19.