Joanne Silberner

As the virus that causes COVID-19 continues its global attack, it has done what scientists predicted it would do — it has given rise to new, slightly different strains. How significant some of those strains will be to the pandemic is now under intense study. Meanwhile, demand for the currently available vaccines is outstripping the early supply, and some scientists have sparked controversy by suggesting holding off on booster shots until more people have had their initial shots.

It may seem counterintuitive, but health officials say that even after you get vaccinated against COVID-19, you still need to practice the usual pandemic precautions, at least for a while. That means steering clear of crowds, continuing to wear a good mask in public, maintaining 6 feet or more of distance from people outside your household and frequently washing your hands. We talked to infectious disease specialists to get a better understanding of why.

Why do I have to continue with precautions after I've been vaccinated?

Updated at 4:45 p.m. ET, Monday, Dec. 21

Now that the Food and Drug Administration has issued an emergency authorization for the first COVID-19 vaccines to be deployed in the U.S., you may have a lot of questions about what this means for you and the people you love. Here's what we know so far:

Who specifically is eligible for the vaccine now?

The major cause of death in children aged 1 to 19 years is not cancer or other another medical condition. It's injury. And by a long shot – 61 percent, versus 9 percent for cancer.

The largest cause of injury was motor vehicle crashes, and next was firearms, according to a study published today in the New England Journal of Medicine. The study sorts through the 20,360 deaths of U.S. children and adolescents in 2016, as counted by the Centers for Disease Control and Prevention.

A new report by a commission empaneled by University College London and the Lancet medical journal offers a thorough — and often surprising — look at the medical and economic impacts of immigration.

It's a major milestone in the fight to recognize mental health and mental illness as global issues: a comprehensive report from the Lancet Commission on Global Mental Health, three years in the making, released this past week at a London summit with royals Prince William and Kate Middleton, Duchess of Cambridge, in attendance to show their support for the cause.

But it was not a celebratory event. Threaded throughout the 45-page report is a lament that the world is ignoring millions of suffering people.

From the front door of the glass-walled gift shop at the Alnwick Garden in the far northeast of England, the scene looks innocent enough. A sapphire green English lawn slopes gently downward, toward traditional, ornamental gardens of rose and bamboo. Across the small valley, water cascades down a terraced fountain.

But a hundred or so plantings kept behind bars in this castle's garden are more menacing — and have much to tell visitors about poison and the evolutionary roots of medicine.