The CDC has given the OK to lift indoor mask mandates in much of the US, and a growing number of states no longer require face coverings in schools. But most experts agree that masks slow school spread of SARS-CoV-2, and whether now is the right time to allow teachers and students to unmask is a matter of debate.

The Scientist spoke with Rachel Zeig-Owens, the director of epidemiology for the World Trade Center Health Program, about what scientists have learned after two decades of studying illness and disease among survivors.

Researchers show that both mice and pigs are capable of oxygenating their blood via the colon—a capacity that, if shared by humans, could be leveraged in the clinic to minimize the need for mechanical ventilation.

Jos Lelieveld of the Max Planck Institute for Chemistry explains how fine particulate might contribute to deaths from COVID-19.

We asked experts for measures people can take that may help boost defenses against COVID-19 and other respiratory diseases.

Electron microscopy revealed that a deadly disease of birds was not a form of flu, but a different type of virus entirely.

In humans, higher oxygen levels during ventilation are tied to an altered bacterial composition in the lungs, and mouse experiments show a causative link.

Milder, cold-causing members of this pathogenic viral family long remained under the radar, although they aren’t entirely harmless.

Super-resolution imaging identifies abnormalities in the hair-like protrusions on a cell’s surface and may help facilitate earlier detection of primary ciliary dyskinesia.

Some US states are waiting for the CDC to send replacement enzymes necessary for carrying out SARS-CoV-2 assays.

In light of recent reports of electronic-cigarette–related illness and death, UNC Chapel Hill professor Robert Tarran discusses the dangerous effects of e-liquids on the lungs.

The World Health Organization estimates that more than 7 million people died in 2012 due to air pollution, making it the number-one environmental risk on the planet.