álgido

decisive, critical, pivotal (of a moment or event); very cold; algid (low body temperature in connection with certain diseases)

“Las autoridades sanitarias alemanas destacaron que aún no se ha alcanzado el punto álgido de la infección, por lo que instaron a los ciudadanos, especialmente en el norte del país—donde se han producido la gran mayoría de casos—a extremar las medidas de higiene.”

Borrowed from Latin algidus (“very cold”), used in medical and poetic senses to describe coldness and stiffness. The figurative sense is perhaps derived from the frequently fatal algid stage of a fever (characterized by coldness as a result of shock). See also Italian algente (“cold”) and English algor.