The In Vitro Evaluation of Povidone-Iodine Against Multiple Ocular Adenoviral Types

Povidone-iodine (P-I) is being touted as a topical antiviral treatment for eye infections caused by adenovirus (Ad). This study evaluated the in vitro antiviral activity of the several P-I concentrations previously used in clinical studies against multiple ocular Ad types commonly associated with eye infections.

The antiviral activity of four concentrations of P-I was compared to vehicle for seven types of Ad after incubating the P-I with Ad at 33°C for various lengths of time. Following incubation and neutralization of the P-I with sodium thiosulfate, viral titers were determined for each Ad type and time point.

Virucidal (99.9%, ≥3-Log₁₀) reductions in titers were produced for 5%, 2%, and 0.4% P-I at 1 min for types Ad5 and Ad7a. Similar reductions were produced at 5 min for types Ad3, Ad4, and Ad8. For type Ad19/64, virucidal reductions took 60 min for 5% P-I and 15 min for 2% and 0.4%. For type Ad37, 60 min (5%), 15 min (2%), and 5 min (0.4%) were required to produce virucidal reductions. There were no virucidal reductions in titers produced by 0.001% P-I.

P-I produced greater than 3-Log₁₀ reductions of titers at 1-5 min for most of the ocular types tested (types Ad3, Ad4, Ad5, Ad7a, and Ad8). However, it took longer (15-60 min) for these reductions to be produced for types Ad19/64 and Ad37. The antiviral activity of P-I may be Ad type dependent.