One possible explanation for the rarity of ocular herpesvirus infections in newborn infants may be the universal application of Credé prophylaxis. To test this hypothesis, a clinically used silver nitrate preparation was instilled in the eyes of rabbits 20 minutes after an ocular inoculation with a strain of type 1 or a strain of type 2 herpesvirus (HSV). With the strain of type 1 HSV, silver nitrate prevented infection with smaller inocula (3,000 plaqueforming units [PFU]), but not with a larger dose (30,000 PFU). With the strain of herpes type 2 there was not prevention of disease with either concentration of inoculum (1,000 and 10,000 PFU). The practical importance of silver nitrate prophylaxis on herpetic infection in the newborn may be small.
Wilkie JS, Easterbrook M, Coleman V, Stevens T. Credé Prophylaxis and Neonatal Corneal Infection With HerpesvirusA Model. Arch Ophthalmol. 1974;91(5):386-388. doi:10.1001/archopht.1974.03900060398013