Dispersal patterns and influence of air travel during the global expansion of SARS-CoV-2 variants of concern.

The Alpha, Beta, and Gamma SARS-CoV-2 variants of concern (VOCs) co-circulated globally during 2020 and 2021, fueling waves of infections. They were displaced by Delta during a third wave worldwide in 2021, which, in turn, was displaced by Omicron in late 2021. In this study, we use phylogenetic and phylogeographic methods to reconstruct the dispersal patterns of VOCs worldwide. We find that source-sink dynamics varied substantially by VOC and identify countries that acted as global and regional hubs of dissemination. We demonstrate the declining role of presumed origin countries of VOCs in their global dispersal, estimating that India contributed <15% of Delta exports and South Africa <1%-2% of Omicron dispersal. We estimate that >80 countries had received introductions of Omicron within 100 days of its emergence, associated with accelerated passenger air travel and higher transmissibility. Our study highlights the rapid dispersal of highly transmissible variants, with implications for genomic surveillance along the hierarchical airline network.

Genomic surveillance reveals dynamic shifts in the connectivity of COVID-19 epidemics.

The maturation of genomic surveillance in the past decade has enabled tracking of the emergence and spread of epidemics at an unprecedented level. During the COVID-19 pandemic, for example, genomic data revealed that local epidemics varied considerably in the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage importation and persistence, likely due to a combination of COVID-19 restrictions and changing connectivity. Here, we show that local COVID-19 epidemics are driven by regional transmission, including across international boundaries, but can become increasingly connected to distant locations following the relaxation of public health interventions. By integrating genomic, mobility, and epidemiological data, we find abundant transmission occurring between both adjacent and distant locations, supported by dynamic mobility patterns. We find that changing connectivity significantly influences local COVID-19 incidence. Our findings demonstrate a complex meaning of "local" when investigating connected epidemics and emphasize the importance of collaborative interventions for pandemic prevention and mitigation.

Coast-to-Coast Spread of SARS-CoV-2 during the Early Epidemic in the United States.

The novel coronavirus SARS-CoV-2 was first detected in the Pacific Northwest region of the United States in January 2020, with subsequent COVID-19 outbreaks detected in all 50 states by early March. To uncover the sources of SARS-CoV-2 introductions and patterns of spread within the United States, we sequenced nine viral genomes from early reported COVID-19 patients in Connecticut. Our phylogenetic analysis places the majority of these genomes with viruses sequenced from Washington state. By coupling our genomic data with domestic and international travel patterns, we show that early SARS-CoV-2 transmission in Connecticut was likely driven by domestic introductions. Moreover, the risk of domestic importation to Connecticut exceeded that of international importation by mid-March regardless of our estimated effects of federal travel restrictions. This study provides evidence of widespread sustained transmission of SARS-CoV-2 within the United States and highlights the critical need for local surveillance.

Travel Surveillance and Genomics Uncover a Hidden Zika Outbreak during the Waning Epidemic.

The Zika epidemic in the Americas has challenged surveillance and control. As the epidemic appears to be waning, it is unclear whether transmission is still ongoing, which is exacerbated by discrepancies in reporting. To uncover locations with lingering outbreaks, we investigated travel-associated Zika cases to identify transmission not captured by reporting. We uncovered an unreported outbreak in Cuba during 2017, a year after peak transmission in neighboring islands. By sequencing Zika virus, we show that the establishment of the virus was delayed by a year and that the ensuing outbreak was sparked by long-lived lineages of Zika virus from other Caribbean islands. Our data suggest that, although mosquito control in Cuba may initially have been effective at mitigating Zika virus transmission, such measures need to be maintained to be effective. Our study highlights how Zika virus may still be "silently" spreading and provides a framework for understanding outbreak dynamics. VIDEO ABSTRACT.

Bikeability and the induced demand for cycling.

To what extent is the volume of urban bicycle traffic affected by the provision of bicycle infrastructure? In this study, we exploit a large dataset of GPS trajectories of bicycle trips in combination with a fine-grained representation of the Copenhagen bicycle-relevant network. We apply a model for bicyclists' choice of route from origin to destination that takes the complete network into account. This enables us to determine bicyclists' preferences for a range of infrastructure and land-use types. We use the estimated preferences to compute a generalized cost of bicycle travel, which we correlate with the number of bicycle trips across a large number of origin-destination pairs. Simulations suggest that the extensive Copenhagen bicycle lane network has caused the number of bicycle trips and the bicycle kilometers traveled to increase by 60% and 90%, respectively, compared with a counterfactual without the bicycle lane network. This translates into an annual benefit of €0.4M per km of bicycle lane owing to changes in generalized travel cost, health, and accidents. Our results thus strongly support the provision of bicycle infrastructure.

Association of vaccination, international travel, public health and social measures with lineage dynamics of SARS-CoV-2.

Continually emerging SARS-CoV-2 variants of concern that can evade immune defenses are driving recurrent epidemic waves of COVID-19 globally. However, the impact of measures to contain the virus and their effect on lineage diversity dynamics are poorly understood. Here, we jointly analyzed international travel, public health and social measures (PHSM), COVID-19 vaccine rollout, SARS-CoV-2 lineage diversity, and the case growth rate (GR) from March 2020 to September 2022 across 63 countries. We showed that despite worldwide vaccine rollout, PHSM are effective in mitigating epidemic waves and lineage diversity. An increase of 10,000 monthly travelers in a single country-to-country route between endemic countries corresponds to a 5.5% (95% CI: 2.9 to 8.2%) rise in local lineage diversity. After accounting for PHSM, natural immunity from previous infections, and waning immunity, we discovered a negative association between the GR of cases and adjusted vaccine coverage (AVC). We also observed a complex relationship between lineage diversity and vaccine rollout. Specifically, we found a significant negative association between lineage diversity and AVC at both low and high levels but not significant at the medium level. Our study deepens the understanding of population immunity and lineage dynamics for future pandemic preparedness and responsiveness.

Disease-specific plasma protein profiles in patients with fever after traveling to tropical areas.

Fever is common among individuals seeking healthcare after traveling to tropical regions. Despite the association with potentially severe disease, the etiology is often not determined. Plasma protein patterns can be informative to understand the host response to infection and can potentially indicate the pathogen causing the disease. In this study, we measured 49 proteins in the plasma of 124 patients with fever after travel to tropical or subtropical regions. The patients had confirmed diagnoses of either malaria, dengue fever, influenza, bacterial respiratory tract infection, or bacterial gastroenteritis, representing the most common etiologies. We used multivariate and machine learning methods to identify combinations of proteins that contributed to distinguishing infected patients from healthy controls, and each other. Malaria displayed the most unique protein signature, indicating a strong immunoregulatory response with high levels of IL10, sTNFRI and II, and sCD25 but low levels of sCD40L. In contrast, bacterial gastroenteritis had high levels of sCD40L, APRIL, and IFN-γ, while dengue was the only infection with elevated IFN-α2. These results suggest that characterization of the inflammatory profile of individuals with fever can help to identify disease-specific host responses, which in turn can be used to guide future research on diagnostic strategies and therapeutic interventions.

Symposium review: high altitude travel with pulmonary vascular disease.

Pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension are the main precapillary forms of pulmonary hypertension (PH) summarized as pulmonary vascular diseases (PVD). PVDs are characterized by exertional dyspnoea and oxygen desaturation, and reduced quality of life and survival. Medical therapies improve life expectancy and physical performance of PVD patients, of whom many wish to participate in professional work and recreational activities including traveling to high altitude. The exposure to the hypobaric hypoxic environment of mountain regions incurs the risk of high altitude adverse events (AEHA) due to severe hypoxaemia exacerbating symptoms and further increase in pulmonary artery pressure, which may lead to right heart decompensation. Recent prospective and randomized trials show that altitude-induced hypoxaemia, pulmonary haemodynamic changes and impairment of exercise performance in PVD patients are in the range found in healthy people. The vast majority of optimally treated stable PVD patients who do not require long-term oxygen therapy at low altitude can tolerate short-term exposure to moderate altitudes up to 2500 m. PVD patients that reveal persistent severe resting hypoxaemia ( S p O 2 ${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$  <80% for >30 min) at 2500 m respond well to supplemental oxygen therapy. Although there are no accurate predictors for AEHA, PVD patients with unfavourable risk profiles at low altitude, such as higher WHO functional class, lower exercise capacity with more pronounced exercise-induced desaturation and more severely impaired haemodynamics, are at increased risk of AEHA. Therefore, doctors with experience in PVD and high-altitude medicine should counsel PVD patients before any high-altitude sojourn. This review aims to summarize recent literature and clinical recommendations about PVD patients travelling to high altitude.

Recent Travel and Tuberculosis in Migrants: Data From a Low-Incidence Country.

Tuberculosis (TB) incidence rates among migrants are higher than those in low-incidence countries. We evaluated smear-positive, pulmonary TB notifications of foreign-born individuals, comparing time since arrival and time since last return travel to the country of origin. TB incidence suggests a time course consistent with recent infection during travel.

Case Management of Imported Crimean-Congo Hemorrhagic Fever, Senegal, July 2023.

We report an imported Crimean-Congo hemorrhagic fever case in Senegal. The patient received PCR confirmation of virus infection 10 days after symptom onset. We identified 46 patient contacts in Senegal; 87.7% were healthcare professionals. Strengthening border crossing and community surveillance systems can help reduce the risks of infectious disease transmission.

Incidence of Legionnaires' Disease among Travelers Visiting Hotels in Germany, 2015-2019.

We determined whether the incidence rates of travel-associated Legionnaires' disease (TALD) in hotels in Germany increased after a previous occurrence and whether control measures required by the European Legionnaires' Disease Surveillance Network after a cluster (>2 cases within 2 years) restored the rate to baseline. We analyzed TALD surveillance data from Germany during 2015-2019; a total of 307 TALD cases (163 domestic, 144 nondomestic) in hotels were reported. The incidence rate ratio was 5.5 (95% CI 3.6-7.9) for a second case and 25 (95% CI 11-50) for a third case after a cluster had occurred, suggesting that control measures initiated after the occurrence of TALD clusters might be inadequate to restore the incidence rate to baseline. Our findings indicate that substantial LD preventive measures should be explored by hotels or other accommodations after the first TALD case occurs to reduce the risk for future infections.

Extrapulmonary Mycobacterium abscessus Infections, France, 2012-20201.

Mycobacterium abscessus infection is challenging to treat. Extrapulmonary M. abscessus infections (EP-MAB) are less common than pulmonary M. abscessus infections. To evaluate treatment regimens, we retrospectively analyzed consecutive microbiologically confirmed EP-MAB cases diagnosed in France during 2012-2020. We studied 45 patients with EP-MAB, including 14 bone and joint infections, 10 skin and soft tissue infections, and 8 lymph node infections. Most (62%) patients had no reported immunodeficiency. In 27 patients, EP-MAB followed healthcare-associated (44%) or environmental (16%) injuries. Of the 45 isolates, 25 were subspecies abscessus, 10 bolletii, and 9 massiliense; 1 was unidentified. Cure was achieved for 36 (80%) patients who received a median antimicrobial regimen of 6 months; 22 (55%) also underwent surgery. Four patients died, and 5 were unavailable for follow-up. EP-MAB predominantly affects immunocompetent patients after an injury; outcomes are favorable. We propose a >6-month regimen of antimicrobial therapy with consideration for surgery and regular patient reassessment.

Bus Riding as Amplification Mechanism for SARS-CoV-2 Transmission, Germany, 20211.

To examine the risk associated with bus riding and identify transmission chains, we investigated a COVID-19 outbreak in Germany in 2021 that involved index case-patients among bus-riding students. We used routine surveillance data, performed laboratory analyses, interviewed case-patients, and conducted a cohort study. We identified 191 case-patients, 65 (34%) of whom were elementary schoolchildren. A phylogenetically unique strain and epidemiologic analyses provided a link between air travelers and cases among bus company staff, schoolchildren, other bus passengers, and their respective household members. The attack rate among bus-riding children at 1 school was ≈4 times higher than among children not taking a bus to that school. The outbreak exemplifies how an airborne agent may be transmitted effectively through (multiple) short (<20 minutes) public transport journeys and may rapidly affect many persons.

Interventional Study of Nonpharmaceutical Measures to Prevent COVID-19 Aboard Cruise Ships.

Cruise ships carrying COVID-19-vaccinated populations applied near-identical nonpharmaceutical measures during July-November 2021; passenger masking was not applied on 2 ships. Infection risk for masked passengers was 14.58 times lower than for unmasked passengers and 19.61 times lower than in the community. Unmasked passengers' risk was slightly lower than community risk.

Sociodemographic and geographic factors impacting radiotherapy recommendation, initiation, and completion for patients with cancer.

BACKGROUND: More than half of patients with cancer receive radiotherapy, which often requires daily treatments for several weeks. The impact of geographic and sociodemographic factors on the odds of patients with cancer being recommended radiotherapy, starting radiotherapy, and completing radiotherapy is not well understood. METHODS: This was a retrospective patient cohort study that included patients diagnosed with one of the 10 most common solid cancers from January 1, 2018, to December 31, 2021, in the National Cancer Database. The primary predictor was radial distance from a patient's home to their cancer treatment hospital. Other covariates included baseline patient characteristics (age, sex, comorbidities, metastatic disease, cancer site), sociodemographic characteristics (race, ethnicity, median income quartile, insurance status), geographic region, and facility type. The three primary outcomes were being recommended radiotherapy, starting recommended radiotherapy, and completing radiotherapy. RESULTS: Of the 3,068,919 patients included, patients living >50 miles away had lower odds of being recommended radiotherapy than those living <10 miles away. Compared to White patients, Asian and Hispanic patients had lower odds of being recommended radiotherapy, and Black patients had lower odds of starting recommended radiotherapy. Uninsured patients, those with Medicaid or Medicare, and patients in lower median income quartiles had lower odds of starting or completing radiotherapy. CONCLUSIONS: Geographic and sociodemographic factors impact access to radiotherapy at different levels in cancer care and understanding these factors could aid policymakers and practices in identifying and supporting at-risk patients.

The impact of travel distance in patient outcomes following revascularization for chronic limb-threatening ischemia.

BACKGROUND: Patient travel distance to the hospital is a key metric of individual and social disadvantage and its impact on the management and outcomes following intervention for chronic limb-threatening ischemia (CLTI) is likely underestimated. We sought to evaluate the effect of travel distance on outcomes in patients undergoing first-time lower extremity revascularization at our institution. METHODS: We retrospectively reviewed all consecutive patients undergoing first-time lower extremity revascularization, both endovascular and open, for CLTI from 2005 to 2014. Patients were stratified into 2 groups based on travel distance from home to hospital greater than or less than 30 miles. Outcomes included reintervention, major amputation, restenosis, primary patency, wound healing, length of stay, length of follow-up and mortality. Kaplan-Meier estimates were used to determine event rates. Logistic and cox regression was used to evaluate for an independent association between travel distance and these outcomes. RESULTS: Of the 1293 patients were identified, 38% traveled >30 miles. Patients with longer travel distances were younger (70 years vs 73 years; P = .001), more likely to undergo open revascularization (65% vs 41%; P < .001), and had similar Wound, Ischemia, foot Infection stages (P = .404). Longer distance travelled was associated with an increase in total hospital length of stay (9.6 days vs 8.6 days; P = .031) and shorter total duration of postoperative follow-up (2.1 years vs 3.0 years; P = .001). At 5 years, there was no definitive difference in the rate of restenosis (hzard ratio [HR], 1.3; 95% confidence interval [CI], 0.91-1.9; P = .155) or reintervention (HR, 1.4; 95% CI, 0.96-2.1; P = .065), but longer travel distance was associated with an increased rate of major amputation (HR, 2.1; 95% CI, 1.2-3.7; P = .011), and death (HR, 1.6; 95% CI, 1.2-2.2; P = .002). Longer travel distance was also associated with higher rate of nonhealing wounds (HR, 2.3; 95% CI, 1.5-3.5; P = .001). CONCLUSIONS: Longer patient travel distance was found to be associated with a lower likelihood of limb salvage and survival in patients undergoing first-time lower extremity revascularization for CLTI. Understanding and addressing the barriers to discharge, need for multidisciplinary follow-up, and appropriate postoperative wound care management will be key in improving outcomes at tertiary care regional specialty centers.

Minimum inhibitory concentrations of Neisseria gonorrhoeae strains in clients of the Amsterdam sexual health clinic with a Dutch versus an international sexual network.

OBJECTIVES: International travel combined with sex may contribute to dissemination of antimicrobial-resistant (AMR) Neisseria gonorrhoeae (Ng). To assess the role of travel in Ng strain susceptibility, we compared minimum inhibitory concentrations (MICs) for five antibiotics (ie, azithromycin, ceftriaxone, cefotaxime, cefixime and ciprofloxacin) in strains from clients with an exclusively Dutch sexual network and clients with an additional international sexual network. METHODS: From 2013 to 2019, we recorded recent residence of sexual partners of clients (and of their partners) with Ng at the Center for Sexual Health of Amsterdam. We categorised clients as having: (1) exclusively sexual partners residing in the Netherlands ('Dutch only') or (2) at least one partner residing outside the Netherlands. We categorised the country of residence of sexual partners by World Bank/EuroVoc regions. We analysed the difference of log-transformed MIC of Ng strains between categories using linear or hurdle regression for each antibiotic. RESULTS: We included 3367 gay and bisexual men who had sex with men (GBMSM), 516 women and 525 men who exclusively had sex with women (MSW) with Ng. Compared with GBMSM with a 'Dutch only' network, GBMSM with: (1) a Western European network had higher MICs for ceftriaxone (ß=0.19, 95% CI=0.08 to 0.29), cefotaxime (ß=0.19, 95% CI=0.08 to 0.31) and cefixime (ß=0.06, 95% CI=0.001 to 0.11); (2) a Southern European network had a higher MIC for cefixime (ß=0.10, 95% CI=0.02 to 0.17); and (3) a sub-Saharan African network had a lower MIC for ciprofloxacin (ß=-1.79, 95% CI=-2.84 to -0.74). In women and MSW, higher MICs were found for ceftriaxone in clients with a Latin American and Caribbean network (ß=0.26, 95% CI=0.02 to 0.51). CONCLUSIONS: For three cephalosporin antibiotics, we found Ng strains with slightly higher MICs in clients with partner(s) from Europe or Latin America and the Caribbean. International travel might contribute to the spread of Ng with lower susceptibility. More understanding of the emergence of AMR Ng is needed.

Sustainability in radiation oncology: opportunities for enhancing patient care and reducing CO2 emissions in breast cancer radiotherapy at selected German centers.

BACKGROUND AND OBJECTIVE: Radiotherapy often entails a substantial travel burden for patients accessing radiation oncology centers. The total travel distance for such treatments is primarily influenced by two factors: fractionation schedules and the distances traveled. Specific data on these aspects are not well documented in Germany. This study aims to quantify the travel distances for routine breast cancer patients of five radiation oncology centers located in metropolitan, urban, and rural areas of Germany and to record the CO2 emissions resulting from travel. METHODS: We analyzed the geographic data of breast cancer patients attending their radiotherapy treatments and calculated travelling distances using Google Maps. Carbon dioxide emissions were estimated assuming a standard 40-miles-per-gallon petrol car emitting 0.168 kg of CO2 per kilometer. RESULT: Addresses of 4198 breast cancer patients treated between 2018 and 2022 were analyzed. Our sample traveled an average of 37.2 km (minimum average: 14.2 km, maximum average: 58.3 km) for each radiation fraction. This yielded an estimated total of 6.2 kg of CO2 emissions per visit, resulting in 156.2 kg of CO2 emissions when assuming 25 visits (planning, treatment, and follow-up). CONCLUSION: Our study highlights the environmental consequences associated with patient commutes for external-beam radiotherapy, indicating that reducing the number of treatment fractions can notably decrease CO2 emissions. Despite certain assumptions such as the mode of transport and possible inaccuracies in patient addresses, optimizing fractionation schedules not only reduces travel requirements but also achieves greater CO2 reductions while keeping improved patient outcomes as the main focus.

The burden of travelling for cervical cancer treatment in Uganda: A mixed-method study.

BACKGROUND: Uganda has one of the highest rates of cervical cancer in the world. Many women are diagnosed and treated with advanced stages of the disease. With only one facility offering comprehensive cervical cancer care in Uganda, many women are required to travel significant distances and spend time away from their homes to receive cervical cancer care. It is important to understand the burden of time away from home while attending treatment because it can inform the expansion of cervical cancer treatment programmes. The aim of this mixed-methods paper is to describe how the distance to cervical cancer treatment locations impacts women in Uganda. METHODS: Women were recruited from 19 September, 2022, to 17 January, 2023, at the Uganda Cancer Institute (UCI) and the cancer clinic at Jinja Regional Referral Hospital (JRRF). Women were eligible for the study if they were (i) aged ≥18 years with a histopathologic diagnosis of cervical cancer; (ii) being treated at the UCI or JRRF for cervical cancer; and (iii) able to provide consent to participate in the study in English, Luganda, Lusoga, Luo, or Runyankole. All participants completed a quantitative survey and a selected group was sampled for semi-structured interviews. Data were analysed using the convergent parallel mixed-methods approach. Descriptive statistics were reported for the quantitative data and qualitative data using an inductive-deductive thematic analysis approach. RESULTS: In all, 351 women participated in the quantitative section of the study and 24 in the qualitative. The quantitative and qualitative findings largely aligned and supported one another. Women reported travelling up to 14 h to receive treatment and 20% noted that they would spend three or more nights away from home during their current visit. Major themes of the qualitative include means of transportation, spending the night away from home, and financial factors. CONCLUSION: Our findings show that travelling to obtain cervical cancer care can be a significant burden for women in Uganda. Approaches should be considered to reduce this burden such as additional satellite cervical cancer clinics or subsidised transportation options.

Regionalizing ovarian cancer cytoreduction to high-volume centers and the impact on patient travel in New York State.

OBJECTIVE: To evaluate the theoretical impact of regionalizing cytoreductive surgery for ovarian cancer (OC) to high-volume facilities on patient travel. METHODS: We retrospectively identified patients with OC who underwent cytoreduction between 1/1/2004-12/31/2018 from the New York State Cancer Registry and Statewide Planning and Research Cooperative System. Hospitals were stratified by low-volume (<21 cytoreductive surgical procedures for OC annually) and high-volume centers (≥21 procedures annually). A simulation was performed; outcomes of interest were driving distance and time between the centroid of the patient's residence zip code and the treating facility zip code. RESULTS: Overall, 60,493 patients met inclusion criteria. Between 2004 and 2018, 210 facilities were performing cytoreductive surgery for OC in New York; 159 facilities (75.7%) met low-volume and 51 (24.3%) met high-volume criteria. Overall, 10,514 patients (17.4%) were treated at low-volume and 49,979 (82.6%) at high-volume facilities. In 2004, 78.2% of patients were treated at high-volume facilities, which increased to 84.6% in 2018 (P < .0001). Median travel distance and time for patients treated at high-volume centers was 12.2 miles (IQR, 5.6-25.5) and 23.0 min (IQR, 15.2-37.0), and 8.2 miles (IQR, 3.7-15.9) and 16.8 min (IQR, 12.4-26.0) for patients treated at low-volume centers. If cytoreductive surgery was centralized to high-volume centers, median distance and time traveled for patients originally treated at low-volume centers would be 11.2 miles (IQR, 3.8-32.3; P < .001) and 20.2 min (IQR, 13.6-43.0; P < .001). CONCLUSIONS: Centralizing cytoreductive surgery for OC to high-volume centers in New York would increase patient travel burden by negligible amounts of distance and time for most patients.