Antibody anxieties

Kathy Nyman, a 59-year-old nurse from Rochester, Minn., and her husband, a physician, both received COVID-19 diagnoses at the end of May. They recovered, and after testing negative, donated plasma twice at Mayo Clinic to support research into a treatment doctors hope will help patients recover from the disease faster.

Nyman said she is “really grateful that God brought us through it” and wants to do what she can to support research on the virus.

At the end of August, the U.S. Food and Drug Administration gave hospitals easier access to so-called convalescent plasma from people like the Nymans who have recovered from COVID-19. They transfuse the plasma into hospitalized patients in hopes the antibodies in the plasma will help fight the disease. The FDA is still studying the safety and efficacy of the treatments, but some early findings look positive.

Patients treated with convalescent plasma in two small studies seemed to show better oxygen levels and less organ failure, and they came off ventilators sooner, Medscape reported. And a study posted on the website MedRxiv but not yet peer-reviewed showed improved survival for nonintubated patients who received convalescent plasma—though not for intubated patients.

Scientists working to understand how antibodies help recovered patients avoid catching the virus again have turned up mixed information.

One study, posted Aug. 15 on MedRxiv, a pre-print server for health sciences, found recovered individuals’ immunity to the coronavirus increased over three months following the first symptoms. The study is under review by the journal Nature. A second pre-print study on Aug. 16 indicated immunity might last for several months. And a preliminary report in Cell on Aug. 11 found people who had mild or asymptomatic cases, as well as their family members, showed strong immune responses. The finding suggests infection or natural exposure might prevent severe COVID-19 cases. All of those studies await peer review.

“This is exactly what you would hope for,” Marion Pepper, an immunologist at the University of Washington, told The New York Times.

But reports surfaced in recent weeks of three people who apparently got COVID-19 a second time. In all three cases, genome sequencing of viral samples showed significant genetic differences between the virus associated with the first infection and the second. That likely means the patients caught a different strain of the virus the second time.

In the first two cases, one involving a man from Hong Kong and the other an elderly patient with a compromised immune system in Denmark, the second infection produced mild to no symptoms.

The third case involved a 25-year-old man who experienced mild symptoms the first time but required hospitalization and oxygen support the second, the University of Nevada, Reno, School of Medicine said on Aug. 27. But Mark Pandori, one of the researchers, stressed that “this is a singular finding” and doesn’t mean reinfection is common.

Darth Vader’s galaxy

Astronomers mapped out an elliptical galaxy an estimated 500 million light-years from Earth that spews out two beams of high energy gamma rays. Images from the National Science Foundation’s Very Long Baseline Array show the rays traveling in opposite directions and producing two lobes of light on either side of the galaxy’s bright core, reminiscent of one of the starships often seen in Star Wars movies.

“The first time I saw the results, I immediately thought it looked like Darth Vader’s TIE fighter spacecraft,” said Matthew Lister, a professor of physics and astronomy at Purdue University. “That was a fun surprise.”

Lister’s paper in The Astrophysical Journal on Aug. 25 explained how astronomers about 90 years ago observed the galaxy beginning to eject jets of material from its core at about one-third the speed of light. The jets collided with other material, stopped, and flowed back toward the galaxy’s center, creating lobes filled with fast-moving particles spiraling around magnetic fields. About 50 years ago, the jets stopped, leaving the glowing lobes behind before starting again about a decade ago.

Astronomers classify the galaxy as active because all of its stars together cannot produce the total amount of light it emits. The extra energy comes from radio waves, X-rays, and gamma rays. Only about one-tenth of active galaxies produce bright lobes.

Scientists think this galaxy’s emissions originate from regions near the supermassive black hole at its center that is about 1 million times as dense as our sun. Near the black hole, friction and gravity cause a hot, swirling disc of gas and dust. —J.B.

Zebra illusions

Scientists have puzzled over the purpose of a zebra’s stripes for more than a century. Some think they provide camouflage or cool the animal by producing convection currents. But a new theory has emerged: Stripes protect the zebra by confusing flies so they either crash land or fly away.

Researchers thought the pattern on a zebra’s coat created an optical illusion that disorients biting flies the same way the rotating stripes on a barber pole appear to move upward. In an Aug. 19 study in Proceedings of the Royal Society B, scientists compared the number of fly landings on horses wearing rugs with a checked pattern to those with stripes. They found the flies avoided landing on either, suggesting that both patterns deter them.

“Not only do these exciting studies bring us closer to understanding one of the world’s most iconic and photogenic species, they will be of great interest to farmers attempting to reduce the damage caused by fly bites and even general horsewear companies,” researcher Tim Caro said. —J.B.

Buried treasure

Teenage volunteers working at an excavation site in central Israel recently uncovered a hoard of 425 Islamic gold coins dating to 1,100 years ago.

“It was amazing. I dug in the ground and when I excavated the soil, saw what looked like very thin leaves,” Oz Cohen told The Times of Israel. “When I looked again I saw these were gold coins. It was really exciting to find such a special and ancient treasure.”

The 845 grams of pure gold would have bought a luxurious house in one of the best neighborhoods in Egypt’s wealthy capital of Fustat at the time, said Robert Kool, a coin expert with the Israel Antiquities Authority.

Archaeologists rarely find much gold because it continues to have a high value. People often melt it down and reuse it from one generation to the next, the excavation directors said. The find could suggest the locals carried out international trade and the coins’ owner expected to return and retrieve them.

The trove included 270 small pieces of gold cut to serve as change. One of those cuttings came from a fragment of a gold coin minted in Constantinople during the reign of Emperor Theophilos between A.D. 829 and 842, Kool said. —J.B.