Here is a summary of some recent studies on COVID-19. They include research that warrants further study to corroborate the findings and that have yet to be certified by peer review.
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.
COVID-19 patients were younger in early 2021 vs late 2020
The average hospitalized COVID-19 patient was younger this past spring than last winter, researchers at a large Pennsylvania health system found. They analyzed data from nearly 39,000 COVID-19 patients, including 7,774 who were hospitalized.
People who tested positive in March and April 2021, when the Alpha variant of the coronavirus was circulating, were younger and less likely to die compared to those diagnosed between November 2020 and January 2021.
Among patients under 50, those who tested positive during the spring were three times as likely to be hospitalized and twice as likely to require ICU admission or mechanical ventilation as those diagnosed in the winter before Alpha was widely circulating, according to a report posted on Wednesday on medRxiv ahead of peer review.
"The widespread availability of highly effective vaccines holds promise," they said, "but infections and deaths from the disease continue...This dynamic is particularly concerning in light of the continued emergence of novel SARS-CoV-2 variants."
U.S. childbirth problems no worse during pandemic
Problematic childbirths did not increase in the United States during the pandemic, researchers found in a study of nearly 838,500 women, including more than 225,000 who gave birth during the pandemic.
There were no differences in rates of preterm birth, blood pressure problems in the mother, stillbirth, low birth weight, placenta problems, Cesarean deliveries, or uncontrolled bleeding after delivery, when comparing the March through December 2020 period to the pre-pandemic years of 2017 to 2019, the research team reported in Obstetrics & Gynecology.
Roughly half of the women had been tested for the coronavirus while pregnant, and about 7% of them had tested positive. There were no differences in childbirth outcomes between these groups.
The authors were not able to distinguish between asymptomatic and symptomatic coronavirus infections, or severity of disease, which could have varying effects on pregnancy outcomes, or whether infection earlier or later in pregnancy made a difference. They only looked at labor and delivery outcomes, not at problems that might have occurred earlier in pregnancy.
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.