You'll see many baby covers that make claims about this, but we simply don't have the tests or research to measure what level of protection Quilbie would offer.  KidsHealth.org suggests: "If you take your child out in an infant carrier, you can place a blanket over the carrier while it's within your view. Make sure the blanket doesn't touch the baby. Wipe down the carrier or stroller when you get home." Given the higher quality materials that Quilbie is made of, it is likely that Quilbie would provide superior protection compared to other baby covers or blankets, but we want to avoid making any claims until we have the resources to do proper testing for validation. In summary, until we can quantify any benefits to blocking germs, bacteria or viruses, Quilbie should not be relied on as a method for protection.