Medical Notes: Week of February 6, 2022

When it comes to illnesses that cause the most deaths, we tend to think of things like heart disease and cancer. But a new study finds that one hidden killer is a lot bigger than most people think: antibiotic-resistant infections. Then, the use of hair products could be altering the course of many pregnancies. And finally, if you’re using a cloth mask to protect yourself against Covid, researchers say it’s a good idea to switch.