If she feels well enough to immerse, then yes. She should arrange with the mikveh to be the last immersion of the evening so as to minimize risk to other women and to enable the mikveh to take appropriate health measures after her immersion.

If she is infectious to her husband, they should follow their doctor's advice. If relations won't be allowed for medical reasons, she may immerse for other forms of physical closeness as the couple do not feel that there is likely to be a problem of hotza'at zera l'vatalah.