Sugar-molecule 'gates' help coronavirus infect cells

Researchers have discovered a sugary residue on the spike of the novel coronavirus that helps it to break into cells and infect them, according to a study published in Nature Chemistry on Thursday.

The molecules that make up the sugary coating, called glycans, act as “gates” that open to let the spike’s receptor-binding domain attach itself to a cell. Without this gate, the receptor-binding domain cannot take the shape it needs to break into the cell, Rommie Amaro of the University of California San Diego, who coauthored the study, said in a press statement. If drugs could be developed that “lock” the glycan gates closed, the virus would be prevented from entering and infecting cells, the researchers said.

More nursing home data points to vaccine concerns

Doctors who immunized 120 nursing home residents against COVID-19 with the Pfizer/BioNTech mRNA vaccine found protective antibodies in only 28% of the residents six months later, compared to 84% of residents immediately after full vaccination. The research, published on medRxiv in advance of peer review, adds to evidence showing that protection from the vaccines wanes over time.

Vaccinated healthcare workers had higher antibody levels than residents, which is not surprising because they were younger and healthier, but they too experienced “significant declines” in protection over time, the researchers reported. Given the “rapid antibody decline” and “the rapid spread of the Delta variant and reports of vaccine breakthrough,” they concluded that booster doses are probably needed.

On Wednesday, the U.S. Centers for Disease Control and Prevention said it would “begin efforts to deliver booster shots directly to residents of long-term care facilities,” starting in September.