Nearly 60% of adults and 75% of children have antibodies indicating that they’ve been infected with Covid-19, according to new data from the US Centers for Disease Control and Prevention.

The data come from an ongoing study of blood samples sent to commercial laboratories across the US.

At the beginning of December, an estimated 34% of Americans had antibodies showing that they had once been infected with the virus that causes Covid-19. By the end of February, after an avalanche of cases caused by the Omicron variant, that number had jumped to 58%.

Was the addition of mitochondria a first step in the formation of complex cells or one of the last? A new study of bacteria tries to answer this contentious question in evolutionary biology.

Analyzing sodium levels in breast cancer tumors can give an accurate indication of how aggressive a cancer is and whether chemotherapy treatments are taking effect, new research has shown.

In a study, by the universities of York and Cambridge and funded by charities Cancer Research UK and Breast Cancer Now, researchers developed a technique using sodium magnetic resonance imaging (MRI) to detect salt levels in breast cancer tumors in mice.

Using this technique, the researchers looked at breast cancer tumors and discovered that salt (sodium) was being accumulated inside cancer cells and that more active tumors accumulate more sodium.