I know this is .02 instead of . 01 but Sawyer says it will filter out a virus. I am no expert on that subject though.
https://www.amazon.com/gp/aw/d/B001CA9PQW/ref=mp_s_a_1_3?ie=UTF8&qid=1487296311&sr=8-3&pi=AC_SX236_SY340_QL65&keywords=Sawyer+gravity&dpPl=1&dpID=41oEChodsuL&ref=plSrch