Ebola outbreak ends and a quiet star is found to host planets

The latest science news, in brief.
A health worker in protective gear and goggles prepares a syringe for a vaccination.

An Ebola vaccine was given to more than 300,000 people during the outbreak in northeastern DRC.

Second-deadliest Ebola outbreak ever ends in Democratic Republic of the Congo

An outbreak of the Ebola virus in the northeastern Democratic Republic of the Congo (DRC) that has been raging since 2018 has officially ended. The World Health Organization (WHO) and the DRC government announced the end on 25 June — 42 days after the last case — but it comes as a fresh Ebola outbreak spreads in the country’s northwest.

“We are extremely proud to have emerged victorious over an epidemic that has lasted a long time,” said Jean-Jacques Muyembe Tamfum, a co-discoverer of Ebola and director of the National Institute for Biomedical Research in Kinshasa, at a press briefing.

The outbreak was declared in August 2018; the virus infected at least 3,470 people, killing 66% of them. That makes it the world’s second-largest outbreak of the haemorrhagic disease, after the 2014–16 West Africa epidemic, which killed more than 11,000 people. Experts also say that the northeastern epidemic — which mainly affected North Kivu and Ituri provinces — was one of the most complex health emergencies the world has ever seen, because it occurred in a region of the DRC plagued by 25 years of war and political instability.

But it was the first Ebola outbreak in which a vaccine for the virus was widely deployed. The vaccine, made by drug company Merck and first tested during the West Africa epidemic, was given to more than 300,000 people who had been in close proximity to people with Ebola, and their contacts. More than 80% of people who were vaccinated didn’t end up with the disease, said Muyembe, and those who developed Ebola after vaccination had milder cases. Two antibody-based drugs also showed promise in a clinical trial.

Ebola responders now want to replicate these tools and strategies in Équateur, a province on the opposite side of the country, where 18 people have been reported to be infected with Ebola since an outbreak was declared there on 1 June.

Many people with coronavirus don’t get a cough or fever

A survey of thousands of people in Italy suggests that a striking share of those infected with the new coronavirus never show classic symptoms of COVID-19. In the study, less than one-third of people infected with SARS‑CoV-2 fell ill with respiratory symptoms or fever.

More than 16,000 people have died of COVID-19 in Lombardy, the epicentre of Italy’s coronavirus outbreak. Piero Poletti at the Bruno Kessler Foundation in Trento, Italy, Marcello Tirani at the Health Protection Agency of Pavia in Italy and their colleagues studied people in Lombardy who had had close contact with an infected person.

Roughly half of these 5,484 contacts became infected themselves (P. Poletti et al. Preprint at; 2020). Of those, 31% developed respiratory symptoms — such as a cough — or a fever. Only 26% of those under the age of 60 did so. As a person’s age increased, so did their odds of experiencing symptoms and becoming ill enough to require intensive care, or to die.

The findings, which have not yet been peer reviewed, could inform hospitals’ outbreak preparations, the authors say.

Illustration of a brown planet, with a large red star in the distance, being crossed by another planet.

An artist’s impression of the two newly discovered planets orbiting GJ 887.Credit: Mark Garlick

Quiet star is home to two intriguing planets

Astronomers have discovered two planets a little more massive than Earth orbiting a nearby star. Unlike many other stars hosting planetary systems, this one is relatively inactive — so it doesn’t emit flares of energy that could hurt the chances of life existing on the planets.

The star, called GJ 887, is just under 3.3 parsecs (10.7 light years) from Earth, in the constellation Piscis Austrinus. It is the brightest red-dwarf star visible from Earth.

Red dwarfs are smaller and cooler than the Sun, and many have planets orbiting them. But most are very active, with magnetic energy roiling their surface and releasing floods of charged particles into space. Astronomers say the planets in these systems might not be able to support life, because their stars constantly blast them with powerful radiation.

By contrast, planets in the newfound system (artist’s impression pictured) could survive relatively unscathed (S. V. Jeffers et al. Science 368, 1477–1481; 2020).

“GJ 887 is exciting because the central star is so quiet,” says Sandra Jeffers, an astronomer at Göttingen University in Germany who led the discovery team. “It’s the best star in close proximity to the Sun to understand whether its planets have atmospheres and whether they have life.”

Nature 583, 13 (2020)

doi: 10.1038/d41586-020-01909-1

Nature Briefing

An essential round-up of science news, opinion and analysis, delivered to your inbox every weekday.