For many, brain fog lingers post-COVID-19

Hello again, dear readers, and welcome to a bonus letters column. We’ve had a deluge of mail, so we’ll jump right in.

— We continue to get questions about COVID-19, which is clearly with us for the long haul. A reader in Long Beach, Calif., echoed several readers in wondering about the aftereffects of the illness. “Can having COVID-19 cause cognitive changes?” they asked. The answer is yes.

People w…