It’s early days for understanding how prior exposure affects flu susceptibility, especially for people born in the last three to four decades.

The questionnaires identified those with prior exposure to each play (in both cases roughly three-quarters of our spectators).

Newborn infants have had no prior exposure to microbes and are particularly vulnerable to infection.

Instead, via prior exposure, people become familiar with outlines, and thereby recognize them the next time they are presented with the same word, or bouma.

Young equines may lack immunity to the disease because they have not had prior exposure.