Microneedling

Before coronavirus shuttered the world, a typical month for Connecticut native Zac Mathias was packed with appointments for microneedling (a collagen-stimulating process that involves repeated pin-pricks all over the face), regular resurfacing hydrafacials, rejuvenating laser treatments and the occasional red-light therapy session.

The three were among a cluster of five people sharing highly similar H.I.V. strains, four of whom had undergone a procedure called platelet-rich plasma microneedling at the spa.