Study during DR Congo's outbreak finds 84% protection from Ebola vaccine

News brief

Ebola workers with PPE — World Bank, Vincent Tremeau / Flickr cc

A real-world study conducted in the Democratic Republic of the Congo (DRC) found that Merck's rVSV-ZEBOV Ebola vaccine was 84% effective against infection during the country's 2018-2020 Ebola outbreak, according to a study yesterday in The Lancet Infectious Diseases.

French and DRC researchers used a test-negative design, analyzing clinical data from 42 Ebola healthcare centers (12 treatment, 9 transit, and 21 decentralized centers). They assessed data on 26,438 people, 1,273 of whom tested positive for Ebola.

The study authors wrote, "This is the first published study to assess the effectiveness of rVSV-ZEBOV outside a clinical trial and amid the most widespread use of the vaccine to date, during the second-largest Ebola virus disease outbreak ever recorded, addressing uncertainties in the real-world effectiveness of the vaccine left open by previous studies."

Protection consistent across groups

They found an overall vaccine effectiveness of 84% (95% credible interval, 70% to 92%) against Ebola virus disease 10 or more days after vaccination. In addition, effectiveness was consistent across sexes and age-groups: It was 80% in females, 86% in males, 80% in children, and 83% in adults.

The authors conclude, "Our findings reinforce the evidence for vaccinating individuals at risk of exposure to Ebola virus as early as possible during epidemics. Even in challenging settings, such as the eastern Democratic Republic of the Congo, rVSV-ZEBOV vaccination is a highly effective tool."

Even in challenging settings, such as the eastern Democratic Republic of the Congo, rVSV-ZEBOV vaccination is a highly effective tool.

In a commentary in the same journal, infectious disease physicians Deborah A. Williamson, MD, PhD, of the University of Melbourne in Australia, and Emma C. Thomson, MD, PhD, with the London School of Hygiene & Tropical Medicine, write, "Importantly, rVSV-ZEBOV effectiveness remained significant even under varied definitions of possible Ebola virus disease exposure, ranging from direct contact with an Ebola virus disease case to residing in areas with confirmed cases. These findings demonstrate the vaccine's robustness in providing protection under real-world conditions where exposure risk to Ebola virus disease can be highly variable."

EPA to fund studies evaluating antimicrobial resistance in wastewater treatment

News brief

Chris Dall, MA

The US Environmental Protection Agency (EPA) yesterday announced $9 million in research grants to measure the environmental and health impact of antimicrobial resistance (AMR) in wastewater.

Oregon State University, the University of Nebraska, the University of Wisconsin-Milwaukee, and the Water Research Foundation in Denver will each receive more than $2 million to study wastewater and sewage sludge treatment systems across the county to better understand how they might aid the evolution and spread of AMR in the environment.

More info needed on AMR in treated wastewater

Wastewater treatment facilities are viewed as a potential focal point for the spread of AMR in the environment because they receive a mixture of antibiotic-resistant bacteria, AMR genes, and antimicrobial drug residues from multiple sources, including farms, households, and hospitals. And while they can reduce the levels of resistant bacteria and AMR genes in the water, they can't eradicate them completely.

Since treated wastewater is discharged into rivers, streams, and other surface waters, that mixture of resistant pathogens and AMR genes may be transmitted to humans and animals. But the extent of transmission, and how it affects humans and animals, is still largely unknown.

"More information is needed to characterize the occurrence and significance of AMR found in treated municipal wastewater effluent and biosolids," the EPA said in a news release. "In addition, new research is needed to provide a better understanding of the impact of AMR on receiving waters and risks related to AMR in treated wastewater discharge, water reuse, and biosolids."

Among the research projects will be efforts to better understand how wastewater treatment processes effect the proliferation and removal of AMR markers, to determine which treatment processes are most effective, and to estimate the human health risks of resistant bacteria and AMR genes in surface waters that receive treated wastewater.

New research finds link between COVID-19 and gestational diabetes

News brief

Lisa Schnirring

COVID-19 infection during the first 21 weeks of pregnancy is associated with a slightly higher risk of gestational diabetes, according to an analysis of insurance claims by Centers for Disease Control and Prevention (CDC) researchers. The team published its findings this week in Clinical Infectious Diseases.

pregnant woman — *Tatyana Tomsickova / iStock*

The investigators analyzed records from nearly 58,000 COVID diagnosis claims in pregnant women from 1 to 21 weeks gestation from March 2020 to October 2022. They compared them with records of more than 115,000 pregnant women who weren't diagnosed with COVID during the same period.

They found a modest but statistically significant higher relative risk (12%) of having a gestational diabetes claim for COVID at 23 weeks gestation or after. The association was significant in all racial groups except for Asian women.

Looking at patterns across periods when different variants were circulating, the researchers found that the risk of gestational diabetes was lower during the Omicron period than when the Delta variant was dominant.

What led to decreased risk over time?

The decreased gestational diabetes risk over time may have resulted from changes in activity during the earlier pandemic months, acquired immunity, or extra protection from vaccination, the group wrote. They noted that, from July 2021 to December 2021, the percentage of vaccination in pregnant women rose from 29.0% to 58.7%.

They concluded that more research is needed to validate the findings and understand possible contributing factors, such as potential hyperinflammatory response, timing of infection, and health determinants such as diet and exercise.