aggression
alien
allergy
anti
antiviral
background
bacteria
bacterium
blue
cartoon
caution
control
cute
danger
disease
flu
funny
germ
hazard
health
humor
hygiene
icon
illness
illustration
infected
infection
isolated
kill
medical
medicine
microbe
microorganism
monster
no
organism
prohibition
protection
protest
risk
safety
science
set
sign
sticker
stop
vaccination
virus
warning