Christian charity dictates that one should not go to Mass when sick with a contagious disease. Parents should not bring sick children to Mass. I once had an obviously sick boy sneeze directly in my face when kneeling during Mass. Despite precautions, three days later I became sick with bronchitis that turned into pneumonia. I lost three week's pay due to my inability to work. Loss of income resulted in not being able to afford travel to Mass for two months. If you're sick, stay home.
All due respect to St. Therese, but she lived in a time when it was not understood how disease spread, much less how to treat and even cure it. It was commonly believed that TB, in particular, was inherited. Should a cloistered nun contract TB today, it is certain she would NOT be permitted to crawl to Mass while she was contagious!