Ridership on the MBTA has peaked, hitting record highs in May with 1.2 million passenger trips per weekday.
That’s up to 2.4 million hands touching T poles and straps every day.
And some of those hands are unwashed.
As the number of riders increases, so do the chances of contacting viruses and germs, experts say.
“In cramped conditions, [the T] is definitely a place where your risk of picking up a viral infection [goes up],” said Rachel Fearns, associate professor of microbiology at Boston University’s School of
Viruses like adenovirus, which can cause diarrhea, pinkeye and common cold symptoms, lurk on surfaces and transmit through touch.
Fearns said the high ridership, combined with passengers grabbing handrails and seat backs, makes getting it easier.
She said people also tend to touch their faces without realizing it, which helps spread viral infections — even in the summer.
According to Dr. Philip M. Tierno Jr., author of a book on germs and director of clinical microbiology at NYU, 80 percent of germs are transmitted by direct or indirect contact.
Tierno said indirect contact occurs when someone coughs in their hand or wipes their nose and then touches something.
“Germs are deposited and then other people touch that surface,” he said. “Then they touch their eyes, mouth or nose, which are portals of entry into the body.”
While the T has a daily routine of cleaning out all its vehicles, including interior scrub-downs, there is nothing they can do to enforce passenger hand-washing.
Follow Steve Annear on Twitter @steveannear.