MBTA GENERAL MANAGER Steve Poftak said on Monday that 63 of the agency’s employees currently have COVID-19, up from 50 last Wednesday.

Poftak said for every worker with COVID-19 there are usually two others affected, mostly because they came in contact with the infected individual and have to quarantine while they await the results of a test. “This begins to have workforce impact,” he said.

Jeffrey Gonneville, the deputy general manager of the T, said the last time the T had 63 infections was during the first COVID-19 surge in April. The peak number then was about 108.

To deal with the vacancies caused by the disease, Gonneville said the agency is slightly adjusting travel times on the T’s subway lines to free up employees who can be used to substitute for workers out because of COVID-19.

Gonneville said the time between train arrivals at stations during peak weekday periods will rise between 20 and 30 seconds on the Red, Orange, and Green subway lines – but not on the Blue Line. He said the added “headway” time will result in fewer workers needed over the course of a day. The Red Line delay, for example, will free up eight workers who can substitute for workers out because of COVID-19.

Poftak said Keolis Commuter Services, the operator of the commuter rail system, is also struggling with infections among its workforce. Poftak told the Fiscal and Management Control Board that roughly 34 Keolis employees had been infected as of the end of November. He said an updated number was not available.