One of the government's top officials in the fight against Ebola, Dr. Anthony Fauci, joined Chris Wallace on Fox News Sunday today and gave an update on Ebola-stricken nurse Nina Pham and revealed that inadequate World Health Organization protocols are likely why Dallas healthcare workers were infected with the deadly virus.

Fauci said he and Pham - who contracted Ebola while treating Thomas Eric Duncan, the first patient to be diagnosed with Ebola in the U.S. - had a long conversation last night and she is doing "quite well" and is in "good spirits."

Although it's dangerous to make predictions with a very serious disease, Fauci said he feels good about the fact that Pham is progressing very well.

Fauci explained that Pham and the other healthcare workers who treated Duncan were following Ebola procedures from the World Health Organization.

Those protocols, unfortunately, are designed for use in the field, not an intensive care setting, and they don't entail covering every aspect of one's skin.

"That is not the optimal way. So, we don't know for sure, but it is likely that she got infected, because [she was] not completely covered."

As for what information he and other health officials communicate to the American people, Fauci said it's a balance between assuring citizens while letting them know there may be a risk.

"Nothing is completely risk-free ... the relative risk of [Ebola], people need to understand, is very, very small. Never zero, but very small."

Watch the clip above to see Fauci explain why he still opposes a travel ban to and from affected West African countries.