The U.S. provides nearly half of the aid for global health, including childhood vaccination, H.I.V. treatment and disease surveillance.

© Olympia De Maismont/Agence France-Presse — Getty Images

Dr. Mark Hyman, a “functional medicine” proponent and longtime friend of Robert F. Kennedy Jr., is finding powerful allies in his bid to treat disease with blood tests and supplements.

© Saul Martinez for The New York Times

California has declared a state of emergency over the virus. We asked experts how concerned they are.

Readers write about the polio vaccine and the dread of the disease in the past. Also: Reducing crime; the Unabomber’s victims; health insurances woes.

Responses to an essay by Andrew Witty, the C.E.O. of UnitedHealth Group. Also: Threats to democracy, in Hungary and America; a check on Trump; avoiding taxes.

Readers worry about cuts to the National Institutes of Health. Also: Maternity wards; overdose deaths; vetting presidential candidates; tech tycoons in charge.

Readers discuss the anger over health insurance set off by the killing of a C.E.O. Also: Gun safety laws; money in politics.

Readers discuss the British vote on the issue and urge actions in the U.S. Also: Safeguarding our food; taxing cow burps in Denmark; a crossword tale.

And why the debate over gender-affirming care could have far-reaching implications.

As a doctor, I’ve been on both sides of frustrating health care debacles.

The state’s ban on gender-affirming medical care for minors passes the constitutional test.

Readers respond to Sarah Wildman’s essay about her daughter’s lessons in facing mortality.

In the case involving medical care for transgender adolescents, ignoring doctors is part of the point.