OFFICES IN Washington D.C. & New Delhi

The Center For Disease Dynamics, Economics & Policy

Weekly Digest: Most early COVID-19 cases linked to travel to Italy, China, and Iran; Novel coronavirus may have been circulating in bats for decades; Study highlights robustness of US vaccine approval system.

Weekly Digest: Most early COVID-19 cases linked to travel to Italy, China, and Iran; Novel coronavirus may have been circulating in bats for decades; Study highlights robustness of US vaccine approval system.


Most early COVID-19 cases were linked to travel to Italy, China, and Iran. An analysis of the early epidemiology of COVID-19 in countries outside of mainland China revealed that first reported COVID-19 cases were commonly linked to travel to Italy, China, and Iran (27, 22, 11 percent of countries, respectively). Travel-links varied by region, with first reported cases in Africa, Europe, and the Americas largely tied to travel to Italy, first cases in the Western Pacific and Southeast Asia tied to travel to China, and first cases in the Eastern Mediterranean tied to travel to Iran. The analysis identified 101 COVID-19 clusters across 29 countries in the first 11 weeks of the outbreak, where clusters related to community gatherings and occupational settings tended to be larger than household clusters; Findings emphasize the importance of physical distancing in preventing transmission of the novel virus. Authors also note that the early epidemiology of COVID-19 in Africa could differ from results, as detection of the virus was low in the early weeks of the pandemic. [The Lancet Infectious Diseases]

Novel coronavirus may have been circulating in bats for decades. A team of researchers assessed the evolution of the novel coronavirus, SARS-C0V-2, and found that the lineage of the virus may have been circulating undetected in bats for decades. Using phylogenetic dating methods to determine ancestral relationships of viral lineages, researchers found that SARS-CoV-2 aligns closely with bat viruses, which may have mutated into the novel coronavirus approximately 40 to 70 years ago. [Nature Microbiology]

mRNA vaccine candidate protects monkeys against novel coronavirus. The mRNA-1273 vaccine candidate, which is currently being tested among humans in phase 3 trials, induced an immune response and protected against viral replication of the SARS-CoV-2 virus in eight monkeys. The vaccine candidate induced antibody levels higher than that seen in serum from humans who have recovered from COVID-19. Two days following exposure to the novel coronavirus, viral replication was not detected in samples from the lungs or nose in a majority of the vaccinated monkeys, signifying that the vaccine provided recipients rapid protection against the virus. [NEJM]

Risk of COVID-19 death among older adults is 13 times higher in nursing homes. A cohort study including 627 long-term care (LTC) facilities in Ontario, Canada found that the incident rate ratio of COVID-19-related death was 13 times higher among residents in LTC compared to community-based individuals in the same age group (IRR: 13.1, 95% CI [9.9-17.3]). Risk of COVID-19-related death among residents in LTC increased sharply over time through early April, and was significantly associated with infections transmitted by staff members. Results emphasize the need for improved infection control, testing, and other resources to protect nursing home residents from poor outcomes related to the novel virus. [JAMA Network Open]

Comorbidities strongly linked to COVID-19 death among non-elderly patients. Findings from a hospital-based case-control study in Hubei province indicated that comorbidities were reported at significantly higher percentages among patients who died from COVID-19 compared to those who recovered (77.1 vs. 42.5 percent, respectively). The most common comorbidities among COVID-19 patients included hypertension, diabetes mellitus, and chronic heart disease. The study found that the association between comorbidities and COVID-19 death decreased with age; Cardiovascular disease and hypertension as well as malignancy and diabetes were tied to increased odds of death among patients 60 years and younger and those 60-70 years old, respectively. However, comorbidities did not play a role in fatal outcomes among patients over 70 years of age. Results suggest that comorbidities significantly impact mortality outcomes, depending on patient age. [Journal of Infection]

Almost half of US adults have risk factors for severe COVID-19. Researchers at the US Centers for Disease Control and Prevention (CDC) estimated that 47.2 percent of US adults have an underlying medical condition (chronic obstructive pulmonary disease, heart disease, diabetes, chronic kidney disease, or obesity) that puts them at an increased risk for severe COVID-19 (defined as hospitalization, ICU admission, mechanical ventilation or death from the illness). The analysis estimated the prevalence of underlying conditions across 3,142 US counties using data from a 2018 nationwide survey and the census. Rural counties and Southeastern states had the highest prevalence of underlying conditions, and the median estimated county prevalence of the selected conditions ranged from 35.4 percent for obesity to 3.4 percent for chronic kidney disease. Results should guide local resource allocation and mitigation strategies in high-risk areas amid the pandemic. [CDC MMWR]

COVID-19 disproportionately affects Latino communities in the US. A new US study suggests that COVID-19 disproportionately affects counties with large Latino populations. Researchers found that rates of COVID-19 diagnosis were higher among counties with a Latino population of at least 17.8 percent (90.9 cases per 100,000 population) compared to other counties (82.0 per 100,0000), although risks of acquiring or dying from the infection varied by region. COVID-19 diagnoses were significantly associated with a larger proportion of individuals who only speak Spanish, employment rates, heart disease deaths, less social distancing, and days since first reported case, while deaths were significantly associated with household occupancy, air pollution, employment rates, days since first reported case, and age. [Annals of Epidemiology]


Drug Resistance and Global Health

Report notes progress in antimicrobial stewardship programs across England. The Patients Association surveyed local clinical commissioning groups in England and reported a 19 percent increase in antimicrobial stewardship programs (ASPs) across primary care compared to survey results from 2016. The 2019 survey found that 64 percent of respondents were achieving their targets for reducing antibiotic use, and more respondents had identified an individual responsible for implementing their ASP compared to 2016 (33 vs. 17 percent). On the contrary, 10 percent of respondents reported having no ASP and 9 percent reported having no target for antibiotic reduction, which highlights room for improvement. [Patients Association]

Study highlights robustness of US vaccine approval system. Results from a retrospective cohort study between 1996 and 2015 indicate that vaccines approved by the US Food and Drug Administration (FDA) are extremely safe, highlighting the country’s robust vaccine approval system. Of the 57 FDA-approved vaccines included in the analysis, 93 percent were supported by randomized controlled trials ranging from 2,200-8,600 participants. Post-marketing surveillance of vaccine safety led to 58 safety-related modifications corresponding to 25 vaccines, which commonly involved issues of limited clinical significance, including population restrictions or allergy warnings (36 and 22 percent, respectively). [Annals of Internal Medicine]

HPV vaccine hesitancy common among parents of adolescents, US survey shows. Findings from a cross-sectional study indicate that more than one-third of US adolescents are not vaccinated against human papillomavirus (HPV), and of this subpopulation, nearly 60 percent of parents do not intend to vaccinate their children against the cancer-causing, sexually-transmitted virus. Lack of parental intent to vaccinate against HPV surpassed 65 percent in the Midwest and was lower in regions that mandate the vaccine, including Washington, DC and Rhode Island (11.2 and 20.4 percent, respectively). Parents of unvaccinated adolescents frequently cited safety concerns (22.8 percent) and the absence of a recommendation from a healthcare provider (22.2 percent) as their reasons for lack of intent to initiate or complete the vaccine series. [The Lancet Public Health]