Table 4.

Activity of cidofovir, cyclic cidofovir and their alkoxyalkyl derivatives against vaccinia, cowpox, monkeypox and variola viruses

Compound	EC50 (μM)
	Vacciniaa	Cowpoxa	Monkeypoxb	Variolab
CDV	46.2 ± 11.9	44.7 ± 6.3	4.6	27.3
HDP-CDV	0.8 ± 0.4	0.6 ± 0.3	0.07	0.1
CCDV	50.6 ± 13.1	48.3 ± 8.0	63.6	45.8
HDP-cCDV	3.8 ± 1.5	2.1 ± 1.9	1.8	0.9

^aKern et al. (2002).

^bHuggins et al. (2002).