“Natural Immunity” from Omicron is Weak and Limited

The new study shows that infection with Omicron does not protect against other variants of COVID-19. In this photo, clear zones on the purple background show the SARS-CoV-2 virus escaping from neutralizing antibodies in patient blood samples.
Credit: Gladstone Institutes

In unvaccinated people, infection with the Omicron variant of SARS-CoV-2 provides little long-term immunity against other variants, according to a new study by researchers at Gladstone Institutes and UC San Francisco (UCSF), published today in the journal Nature.

In experiments using mice and blood samples from donors who were infected with Omicron, the team found that the Omicron variant induces only a weak immune response. In vaccinated individuals, this response—while weak—helped strengthen overall protection against a variety of COVID-19 strains. In those without prior vaccination, however, the immune response failed to confer broad, robust protection against other strains.

“In the unvaccinated population, an infection with Omicron might be roughly equivalent to getting one shot of a vaccine,” says Melanie Ott, MD, PhD, director of the Gladstone Institute of Virology and co-senior author of the new work. “It confers a little bit of protection against COVID-19, but it’s not very broad.”

Soil Microbes Use Different Pathways to Metabolize Carbon

Credit: Victor O. Leshyk/Northern Arizona University

Much of what scientists think about soil metabolism may be wrong. New evidence from Northern Arizona University suggests that microbes in different soils use different biochemical pathways to process nutrients, respire and grow. The study, published in Plant and Soil, upends long-held assumptions in the field of soil ecology and calls for more investigation and higher-resolution methods to be applied to what has been a black box for the field.

“As ecologists, we generally don’t think about soil metabolism in terms of pathways,” said Paul Dijkstra, research professor of biology in the Center for Ecosystem Science and Society at NAU and lead author of the study. “But we now have evidence that metabolism differs from soil to soil. We’re the first to see that.”

“We’ve learned that biochemistry—more specifically, the metabolic pathways the soil microbiota chooses—matters, and it matters a lot,” said co-author Michaela Dippold, a professor of bio-geosphere interactions at University of Tübingen in Germany. “Our field urgently needs to develop experimental approaches that quantify maintenance energy demand and underlying respiration in a robust way. It’s a challenge to which future soil ecology research will have to respond.”

Meet the forest microbes that can survive megafires

The image highlights the diversity in colors and morphologies of microbes obtained from Soberanes Fire-burned soil.
Credit: Jenna Maddox/UCR

New UC Riverside research shows fungi and bacteria able to survive redwood tanoak forest megafires are microbial “cousins” that often increase in abundance after feeling the flames.

Fires of unprecedented size and intensity, called megafires, are becoming increasingly common. In the West, climate change is causing rising temperatures and earlier snow melting, extending the dry season when forests are most vulnerable to burning.

Though some ecosystems are adapted for less intense fires, little is known about how plants or their associated soil microbiomes respond to megafires, particularly in California’s charismatic redwood tanoak forests.

“It’s not likely plants can recover from megafires without beneficial fungi that supply roots with nutrients, or bacteria that transform extra carbon and nitrogen in post-fire soil,” said Sydney Glassman, UCR mycologist and lead study author. “Understanding the microbes is key to any restoration effort.”

The UCR team is contributing to this understanding with a paper in the journal Molecular Ecology.